Green space and mortality in European cities: a health impact assessment study

Effect of tree canopy cover on air pollution-related mortality in European cities: an integrated approach

BACKGROUND

In urban areas, fine particles (PM2·5), nitrogen dioxide (NO2), and tropospheric ozone (O3) are the most harmful air pollutants for human health. Urban greening is seen as a strategy for co-benefitting air quality, climate, and citizens' wellbeing. We aimed to estimate the changes in tree cover, the mortality burden attributable to air pollution, and the mortality that could be potentially prevented by increasing tree coverage in European cities.

METHODS

We did a quantitative health impact assessment to estimate the effect of mean tree cover on air pollutants levels and PM2·5-related, NO2-related, and O3-related mortality (all ages) in 744 European urban centres, with more than 50 000 inhabitants, across 36 countries. We did all analyses at the city-wide scale.

FINDINGS

Between 2000 and 2019, the mean tree coverage increased by 0·76 percentage points, with 73·5% of the urban centres showing greener coverage, whereas mortality burdens declined by on average 3·39% (SD 0·28) in all urban centres. In 2019, about 25% of the total population lived in areas with a mean tree canopy coverage over 30%. Compared with the current tree cover, each five percentage point increase in tree canopy cover could facilitate an air quality improvement of 2·8% for annual PM2·5 mean concentrations, 1·4% for annual NO2 mean concentrations, and 1·2% for summertime mean of the daily maximum 8-h O3 concentrations.

INTERPRETATION

We estimated that each five percentage point increase in tree canopy would potentially prevent 4727 premature deaths (95% CI 2067-7475) related to air pollution annually across the 744 European urban centres. We also estimated that reaching a canopy cover of 30% within each city could potentially prevent 11974 premature deaths (95% CI 7775-14 390) each year. Our results highlighted the potential public health benefits of increasing tree coverage in urban environments, contributing to sustainable, liveable, and healthier cities.

FUNDING

LIFE financial instrument of the EU; Romanian National Research Authority; Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación; Generalitat Valenciana; The European Regional Development Fund; and National Natural Science Foundation of China.

Building a Healthy Urban Design Index (HUDI): how to promote health and sustainability in European cities

BACKGROUND

As global urbanisation accelerates, alongside declining environmental quality and increasing climate challenges, it is increasingly vital for urban planners and policy makers to integrate health and wellbeing considerations into urban planning. This study introduces the Healthy Urban Design Index (HUDI), a high-resolution spatial index developed for European cities. HUDI combines policy-relevant indicators related to urban design, sustainable transportation, environmental quality, and greenspace accessibility-key factors influencing human health and well-being. Unlike existing indices, which often focus on few or large metropolitan cities and lack spatial granularity, HUDI offers high resolution and extends its scope to small-sized and medium-sized cities, home to over 50% of Europe's population.

METHODS

We analysed 917 European cities in total, 916 cities and one larger city, on the basis of the 2018 Urban Audit database. Using open-source spatial data, we mapped cities at a fine 250 m grid cell scale. To compare cities effectively, we grouped them into five city clusters on the basis of population size, following the definition of the Organisation for Economic Co-operation and Development: large metropolitan (11), metropolitan (53), medium-sized (177) and small (638) cities, and small towns (38). A set of 13 indicators, across four overarching domains of urban design, sustainable transportation, environmental quality, and green space accessibility was calculated spatially at the 250 m grid cell scale and then aggregated to the city level. The 13 indicators were optimal dwelling density, compactness, mid-rise development, permeability, opportunity to walk, opportunity to cycle, public transport stops, air quality (PM2·5 and NO2), surrounding greenness (Normalized Difference Vegetation Index), lower urban heat islands, universal access to green spaces, and access to large green spaces. To ensure comparability, all indicators were standardised on a scale from 0 to 10, considering data quality, indicator target levels, and specific evaluation criteria. The HUDI was then calculated by applying different weights to these indicators, allowing us to rank cities within their respective city size cluster. We visualised overall city performance using spider plots and did Local Moran's I and Local Indicators of Spatial Association analyses to pinpoint areas with poor urban planning. We did sensitivity tests and correlation analyses, incorporating external datasets where available, to validate our findings.

FINDINGS

HUDI scores ranged from 2·9 to nearly 7 of 10, showing that there is still room for improvement in creating healthier urban environments across European cities. Larger metropolitan cities, particularly in northern Europe and parts of Spain, tended to score well in the urban design and sustainable transportation domains. In contrast, medium and smaller-sized cities did better in the environmental quality domain. However, smaller cities often struggled with the green space accessibility domain, as fewer parks and green spaces were accessible via walking or cycling, despite having plenty of surrounding greenery. A clear east-west divide exists, with cities in Western Europe, such as those in the UK, Spain, and Sweden, achieving the highest HUDI scores, whereas eastern European cities, particularly in Romania, Bulgaria, and Poland, scored lower. These findings highlight how city size and regional factors shape urban sustainability and public health outcomes.

INTERPRETATION

The HUDI is a large-scale, high-resolution, open-data tool that measures key urban health factors across nearly 1000 European cities of different sizes. As an open-source resource, HUDI provides valuable, data-driven insights to help cities identify strengths, weaknesses, and urban management areas needing improvement. By offering clear, measurable indicators, it helps policy makers and urban planners pinpoint problem areas and make informed decisions to improve public health and sustainability. HUDI is a dynamic tool, not a definitive ranking. By clustering cities by size, it enables comparisons, knowledge, and best practice sharing. Further research is needed to refine HUDI and expand its indicators and cities as better data become available. A key strength of HUDI is its ability to highlight data gaps and encourage better data collection. We call on researchers and urban planners to support HUDI development by sharing data and code on GitHub and Zenodo, helping track urban health and sustainability progress more effectively.

FUNDING

The Spanish Ministry of Science and Innovation, Generalitat de Catalunya, Centro de Investigación Biomédica en red Epidemiología y Salud Pública, Urban Burden of Disease Estimation for Policy Making Horizon Europe project, Barcelona Institute for Global Health, University of Turin, ISI Foundation, and US Department of Energy.

Cytogenetic evaluation of vaginal and buccal epithelium of pregnant women living in conditions of radioactive, chemical and combined environmental contamination

INTRODUCTION

Many pollutants constantly worsen the ecological situation, thereby causing irreparable harm to the health of the population. Technogenic impact on the biosphere has become one of the significant factors dictating our conditions of existence on Earth.

PURPOSE OF THE STUDY

to conduct a comparative analysis of the frequency of cytogenetic abnormalities, indicators of proliferation disorders and nuclear destruction of vaginal and buccal epithelium of pregnant women 26-33 years old living in conditions of radioactive, chemical and combined environmental contamination of the Bryansk region.

METHODS

micronucleus test, staining method by Kvik, fluorescence method, immunocytochemistry method, Shapiro-Wilk test, Mann-Whitney U test.

RESULTS

the frequency of cytogenetic abnormalities, indicators of proliferation disorders and nuclear destruction in the vaginal epithelium of pregnant women living in areas of radioactive, chemical and combined environmental contamination is 1.3-4.9 times higher, and in the buccal epithelium 1.6-7.8 times higher compared to ecologically safe (control) areas (p < 0.01-0.001). The combined effect of radioactive contamination and chemical pollution resulted in a significantly higher (increase from 12.8% to 81.4% in vaginal epithelium and from 22.6% to 2.3 times in buccal epithelium) frequency of cells with micronuclei, cells with protrusions, binuclear cells, cells with double nuclei, as well as cells with karyopyknosis and karyolysis in pregnant women compared to areas with only one pollution factor.

CONCLUSION

The results demonstrate the synergistic effects of radiation contamination and chemical pollution on the cytogenetic status of pregnant women.

A Europe-wide characterization of the external exposome: A spatio-temporal analysis

BACKGROUND

Harmonised data on external environmental exposures are essential for multi-cohort exposome studies. This paper describes the development of fine-spatial resolution models and resulting exposure maps for 33 major exposome factors -including physical-chemical, built, social, and food environments-across Europe from 2000 to 2020, and examines their spatial and temporal interrelations.

METHODS

New fine spatial resolution Europe-wide models were developed for annual/monthly average air pollution, daily temperature, and annual-average road-traffic noise, combined with post-processing of existing data on green, blue, and grey spaces (imperviousness), walkability, light-at-night, and urbanicity. Exposure metrics relevant for epidemiological studies were developed for all exposome factors, with correlations calculated at European and country levels. Stability and trends over time were assessed for 18 factors.

RESULTS

At the European level, most environmental factors showed weak correlations (R < 0.4), except NO2, which showed moderate to strong correlations with built environment factors. Country-level correlations varied. Annual average exposure surfaces were stable over time, with strong correlations between early and late time points for all factors except O3​ (R = 0.66). Trends indicated decreases in air pollution and increases in temperature, green space, and imperviousness, while trends in light-at-night and O3​ were mixed across Europe.

CONCLUSIONS

This comprehensive analysis of the temporal and spatial relationships between external exposome factors across a large geographical area show low to moderate correlations between exposome factors. Annual average exposure surfaces were also stable over time across Europe. These findings support both the utility of multi-exposure epidemiological analyses, and that any modest temporal misalignment between exposure assessment and follow-up period of health studies is not critical. The data described in his paper are openly available to researchers.

Health burden and inequities of urban environmental stressors in Sofia, Bulgaria

BACKGROUND

The number of studies on the health impacts of urban environmental stressors has been growing. However, research for South-Eastern Europe remains limited. We conducted a baseline Health Impact Assessment for Sofia, Bulgaria, focusing on air pollution, green space, road-traffic noise, and urban heat island (UHI) exposure aiming to promote discussions on sustainable, health-centric urban and transport planning policies.

METHODS

The analysis was conducted at the neighbourhood level (n = 4969). The study population included 1,168,382 inhabitants, considering adults and children. Data were retrieved from Europe-wide and local exposure models, local censuses and surveys. We used comparative risk assessment methodology, comparing baseline with optimal scenarios for health, such as meeting World Health Organization (WHO) air quality and road-traffic noise guidelines, green space recommendations, and no UHI effect. We also examined exposure and health impact distributions by area-level socioeconomic status (SES). We approximated differences in baseline disease rates by SES using data from local surveys. The results were stratified by SES quartiles and analysed spatially using global and local bivariate Moran's I statistics, the latter to identify priority areas for intervention based on SES, environmental exposures, and health outcomes.

RESULTS

All Sofia residents lived in neighbourhoods where particulate matter with diameter ≤2.5 μm (PM2.5) and nitrogen dioxide (NO2) levels exceeded the WHO air quality guidelines, with mean noise levels of 62.2 dB(A) Lday, 77 % lacking sufficient availability of green space, and an average summer UHI of 2.5 °C. The largest mortality burden was from PM2.5 exposure (1939 annual deaths (95 % CI: 1349-2571)), followed by NO2 (1172 annual deaths (444-2027)), road-traffic noise (902 annual deaths (556-1311)), insufficient green space (217 annual deaths (169-262)), and UHI (95 summer deaths (58-130)). PM2.5 contributed to 17-21 % of cardiovascular disease cases, while noise accounted for 5 % of Ischaemic Heart Disease and stroke cases. NO2, noise, and UHI exposures tended to be higher in higher SES areas, while PM2.5 tended to be lower. Spatial analysis revealed that central areas, with high-SES populations, and northern, north-eastern, and north-western areas, with lower-SES populations, all experience high exposure and health impacts.

CONCLUSIONS

The analysis showed a significant health burden from urban environmental stressors in Sofia, with an uneven distribution across SES groups. Health-promoting policy interventions should consider both environmental and socioeconomic factors to prioritize areas for action.

Stakeholder perceptions of biodiversity in urban residential areas

This study investigates differences in understanding in stakeholder group perceptions of biodiversity in urban neighborhoods of Warsaw, Poland, focusing on and support for biodiversity among architects, landscape architects, public administrators and local activists. The research assesses how these professional groups perceive key elements of biodiversity and prioritize aspects of urban green space. We conducted a structured survey using a Computer-Assisted Web Interview (CAWI) targeting 144 participants from the aforementioned stakeholder groups. Participants evaluated biodiversity-related elements, such as the presence of multi-layered vegetation, deadwood, insects, and animal-friendly structures, and indicated their preferences for green space designs through photomontages with varying biodiversity levels. Groups differed in how they understood and value specific aspects of biodiversity such as the presence of dead wood or insects. Results revealed that 81 % of stakeholders expressed positive attitudes toward nature, yet significant differences emerged in their preferences and willingness to incorporate biodiverse elements into designs. Local activists demonstrated the strongest support for biodiverse landscapes, favoring naturalistic features like dense vegetation and deadwood, while architects and public administration officials exhibited reservations, citing concerns about safety, aesthetics, and maintenance costs. Landscape architects occupied a middle ground, showing awareness of biodiversity benefits but adopting a cautious approach. These findings underscore the need for collaborative efforts to bridge the gap between stakeholder priorities and promote biodiverse urban spaces, with particular attention to public concerns and misperceptions about biodiversity. Public apprehension towards dense vegetation particularly needs to be addressed. Highlighting the benefits of biodiverse spaces can foster acceptance among varying stakeholder groups.

Association of polysocial risk score, cardiovascular health status, and the risk of premature mortality: Findings from the UK Biobank

BACKGROUND

Evidence of the cumulative effects of social risk factors on premature mortality is quite limited. We aimed to examine the association between cumulative social risk factors and premature mortality by constructing a polysocial risk score, and to explore the influence of cardiovascular health on this association.

METHODS

A polysocial risk score was constructed by summing 11 social determinants of health. A cardiovascular health (CVH) score was calculated following the algorithm of "Life's Essential 8". Premature mortality was defined as death at an age younger than 75. Cox proportional hazards model was conducted.

RESULTS

A total of 314,039 participants in the UK Biobank were included (median age 56.0 years, 53.1% women). During a median of 12.7 years of follow-up, 13,888 premature deaths were reported. Compared with participants who had a low polysocial risk score (≤3), participants with a high polysocial risk score (≥7) were more than twice as likely to die prematurely in the follow-up period (HR 2.18, 95% CI 2.06-2.30). Compared with participants with ideal CVH and low polysocial risk score, those with poor CVH and high polysocial risk score had the highest risk of premature mortality (HR 5.25, 95% CI 4.48-6.14). A significant interaction was found between CVH status and polysocial risk score on premature mortality risk (P for interaction <0.001).

CONCLUSIONS

Polysocial risk score was associated with an increased risk of premature mortality, the association was exacerbated by poor CVH. Our findings indicate that limiting social inequities and encouraging people to achieve an ideal CVH are essential to reducing the burden of premature mortality.

Residential Greenness Is Associated with Lower Thyroid Nodule Prevalence: A Nationwide Study in China

Background: The prevalence of thyroid nodules is increasing globally. This study explored the association between residential greenness and thyroid nodule prevalence. Methods: Data were collected from a national cross-sectional survey of 73,728 participants across 31 provinces in mainland China. Residential greenness was assessed with the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI). Thyroid nodules >10 mm in diameter were diagnosed via ultrasound. We used quartile comparisons of the NDVI and EVI to compare nodule prevalence and employed logistic regression and restricted cubic spline analyses to examine nodules' associations with greenness. Interaction and sensitivity analyses were performed to test robustness. Results: A total of 73,728 participants were included in this study. The prevalence of 10 mm thyroid nodules decreased across NDVI500 quartiles: Q1: 7.99% (7.59-8.39%), Q2: 10.04% (9.60-10.48%), Q3: 6.59% (6.23-6.95%), and Q4: 5.20% (4.88-5.52%) (p for trend <0.001). The prevalence was 5.25% (95% confidence interval [CI]: 5.02-5.49%) in males and 9.09% (CI: 8.80-9.39%) in females. Logistic regression analysis showed that greater residential greenness was associated with a lower prevalence of thyroid nodules after adjusting for all covariates. This association was observed for both continuous greenness measures (NDVI500: odds ratio [OR] = 0.20, CI: 0.16-0.25; EVI500: OR = 0.08, CI: 0.06-0.12) and across quartiles (NDVI500 Q4: OR = 0.53, CI: 0.48-0.58; EVI500 Q4: OR = 0.55, CI: 0.51-0.60; both compared to Q1). Multiple sensitivity analyses confirmed this negative association, including the use of an alternative thyroid nodule definition (5 mm threshold), exclusion of individuals with cysts on ultrasound, and subgroup analyses excluding individuals with autoimmune thyroid antibody positivity, goiter, or both. In all these sensitivity analyses, NDVI and EVI data were assessed using both 500 m and 1000 m buffers. Conclusion: Our study is the first to identify an association between higher levels of residential greenness and a lower prevalence of thyroid nodules.

A health impact assessment of progress towards urban nature targets in the 96 C40 cities

BACKGROUND

Urban greenspaces (eg, parks and trees) and blue spaces (eg, rivers and coasts) improve climate regulation and human health. In 2021, the mayors of 31 cities in the C40 Climate Leadership Group set 2030 targets for the percentage of urban greenspace and population with nearby natural (green or blue) space. We quantified annual all-cause mortality reductions from progress towards these targets for C40's 96 member cities.

METHODS

We conducted a quantitative health impact assessment, testing three illustrative scenarios to increase urban greenspace: uniformly across space, in areas with the least nature, and in the most populated areas. We converted one percentage point progress towards each target in terms of the Normalized Difference Vegetation Index (NDVI) using previously published associations. We used mortality rate estimates from The Global Burden of Diseases, Injuries, and Risk Factors Study, population data from WorldPop, and a pooled hazard ratio of NDVI and all-cause mortality from an epidemiological meta-analysis.

FINDINGS

Uniformly increasing greenspace by 1% yielded an estimated 96-city median of 1·77 (range 0·65-3·52, IQR 1·46-2·19) fewer annual premature deaths per 100 000 population; increasing the population percentage with nearby natural space yielded an estimated median of 0·56 (range 0·11-1·70, IQR 0·44-0·69) fewer annual premature deaths per 100 000 population. On average, compared with uniform increases, adding greenspace in the least natural areas provided 1·4-1·7 times (depending on the target) the health benefits, and adding greenspace in the most populated areas provided 2·7 times the health benefits.

INTERPRETATION

The geographical distribution of greenspace expansion influences the magnitude of associated health benefits across varied urban contexts. Health benefits are largest when greenspace is added near population centres.

FUNDING

Wellcome Trust, NASA, and The George Washington University.

The epidemiologic case for urban health: conceptualizing and measuring the magnitude of challenges and potential benefits

We discuss how epidemiology has been and can continue to be used to advance understanding of the links between urban areas and health informed by an existing urban-health conceptual framework. This framework considers urban areas as contexts for health, determinants of health and modifiers of health pathways, and part of a complex system that affects health. We highlight opportunities for descriptive epidemiology to inform the context of urban health, for example, by characterizing the social and physical environments that give rise to health and the actions that change those conditions. We then describe inferential tools for evaluating the impact of group-level actions (e.g., interventions, policies) on urban health, providing some examples, and describing assumptions and challenges. Finally, we discuss opportunities and challenges of applying systems thinking and methods to advance urban health. While different conceptual frames lead to different insights, each perspective demonstrates that urban health is a major and growing challenge. The effectiveness of urban health knowledge, action, and policy as the world continues to urbanize can be informed by applying and expanding upon research and surveillance methods described here.

Physical urban environment and cardiometabolic diseases in the five largest Bulgarian cities

This study investigated the associations between residential environmental characteristics and the prevalence of cardiometabolic diseases in the five largest Bulgarian cities. Representative cross-sectional survey data (N = 4640 adults) was collected in Sofia, Plovdiv, Varna, Burgas, and Ruse. Participants self-reported diagnosis or medication intake for hypertension, ischemic heart disease (IHD), stroke, and diabetes mellitus, as well as domestic burning of solid fuel and having a domestic garden. Residential addresses were linked to greenspace (overall vegetation level, tree cover, urban greenspace), bluespace, walkability, air pollution (NO2), and traffic noise (Lden). In the 300 m buffer, bluespace presence was inversely associated with hypertension (odds ratio [OR] = 0.67; 95% CI: 0.45, 1.00), IHD (OR = 0.45; 95% CI: 0.21, 0.99), and diabetes (OR = 0.51; 95% CI: 0.25, 1.04). Higher walkability and tree cover were inversely associated with hypertension (OR per 2 units = 0.85; 95% CI: 0.75, 0.96) and diabetes (OR per 10% = 0.77; 95% CI: 0.62, 0.97), respectively. These associations were stronger in larger buffers. Solid fuel burning was associated with IHD (OR = 1.63; 95% CI: 1.07, 2.50). There was an indication of a positive association between aircraft Lden and both stroke and IHD. The direction of the associations for domestic gardens, NO2, road traffic and railway Lden was counterintuitive. We detected some nonlinear associations. In conclusion, people living in urban neighborhoods that were more walkable, closer to bluespace, and greener had lower prevalence of cardiometabolic diseases, while solid fuel burning was associated with higher odds of cardiovascular diseases. Unexpected associations with some exposures may be due to unaccounted for urban fabric characteristics. This study is among the first assessing an understudied region in Southeastern Europe. Its findings have the potential to inform public discourse and provide evidence to support the implementation of urban design conducive to cardiometabolic health.

Harnessing Evolution and Biomimetics to Enhance Planetary Health: Kidney Insights

Planetary health encompasses the understanding that the long-term well-being of humanity is intrinsically linked to the health of global ecological systems. Unfortunately, current practices often overlook this principle, leading to a human-oriented (anthropocentric) worldview that has resulted in heightened greenhouse gas emissions, increased heat stress, lack of access to clean water, and pollution, threatening both the environment and health and survival of Homo sapiens and countless other species. One significant consequence of these environmental changes is the exacerbation of inflammatory and oxidative stressors, which not only contributes to common lifestyle diseases but also accelerates the aging process. We advocate for a shift away from our current anthropocentric frameworks to an approach that focuses on nature's solutions that developed from natural selection over the eons. This approach, which encompasses the field of biomimicry, may provide insights that can help protect against an inflammatory phenotype to mitigate physiological and cellular senescence and provide a buffer against environmental stressors. Gaining insights from how animals have developed ingenious approaches to combat adversity through the evolutionary process of natural selection not only provides solutions for climate change but also confronts the rising burden of lifestyle diseases that accumulate with age.

Co-benefits of nature-based solutions: A health impact assessment of the Barcelona Green Corridor (Eixos Verds) plan

INTRODUCTION

The Green Corridors Plan (Eixos Verds Plan), proposed by the Barcelona City Council, aims to enhance urban well-being, environmental sustainability, and resilience by transforming one in every three streets into green corridors. Although initially designed for city-wide implementation, only the first phase, focused on the centric Eixample district, has been completed, and the overall plan implementation has been postponed. Our aim is to evaluate the health co-benefits of implementing the Green Corridors plan citywide, focusing on the direct effects of increased exposure to greenness and the impact of temperature reduction on mortality.

METHODS

We conducted a comprehensive Health Impact Assessment (HIA) considering direct effects of expanding green spaces (GS) and the impact on temperature reduction. Preventable mortality at the census tract level for adult residents was estimated, and to address uncertainties, we performed Monte Carlo iterations. We computed the percentage increase in GS (land use) and tree cover and converted them into Normalized Difference Vegetation Index (NDVI) to conduct the HIA, employing a Generalized Additive Model (GAM). We used the Weather Research and Forecasting model (WRF) coupled with the urban parameterizations "Building Effect Parameterization" (BEP) and "Building Energy Model" (BEM) for temperature modelling. Hourly temperatures from 25/06/2015 to 25/07/2015 were simulated, both with and without Green Corridors Plan implementation.

RESULTS

City-wide implementation of the Green Corridors plan would increase average GS by 3.64 % (IQR: 2.17 % - 4.40 %) and NDVI by 0.286 (IQR: 0.256-0.304) per census tract. This could potentially prevent 178 premature deaths annually (95 % CI: 116-247), equating to 13 deaths per 100,000 inhabitants (95 % CI: 9-19). The average daily temperature reduction per census tract was estimated at 0.05 °C, with a maximum reduction of 0.42 °C. Temperature reduction could potentially prevent 5 deaths during the simulated month. Additionally, we estimated a mean decrease in the thermal stress of 0.11 °C, reaching up to 1.48 °C at its peak.

CONCLUSION

The Green Corridors plan can make significant contributions to a healthier urban environment. To address climate and especially heat impacts, complementary strategies to achieve more substantial temperature reduction are needed. Overall, our findings underscore the potential of nature-based solutions (NbS), exemplified by the Green Corridors Plan, in creating more sustainable and health-promoting urban environments.

Association between urban green space and transmission of COVID-19 in Oslo, Norway: A Bayesian SIR modeling approach

BACKGROUND

Access to green spaces can provide opportunities for physical activities and social interactions in urban areas during times with strict social distancing. In particular COVID-19 transmission is reduced in ventilated areas. During several waves of the pandemic, this study explores the association between access to urban green spaces and COVID-19 transmission at the district level in Norway's capital, Oslo.

METHODS

We used daily numbers of confirmed laboratory PCR tests on district levels reported from the second to the fifth wave of the COVID-19 pandemic, from October 15, 2020 to April 15, 2022 in Oslo. We included the population's access to urban green spaces using two objective measurements: percentage of green area (%Ga) and vegetation cover (NDVI) using 300 and 1000 m buffers. The socio-demographic variables percentage of low-income population, average life expectancy and population density were also included. A Bayesian Susceptible-Infected-Removed (SIR) model was used to take advantage of the daily updated data on COVID-19 incidence and account for spatial and temporal dependencies in the statistical analysis.

RESULTS

We found that low income as well as population density were significantly associated with incidence of COVID-19, but for the second and third waves only. For the second wave, a one percent increase in the proportion with low income at district level increased the risk of COVID-19 by 7 % (95 % CI: 3 % - 11 %) We did not find associations between access to green space and incidence rate for any of the buffer sizes. The second and third waves were more governed by socio-demographic factors than the fourth and fifth wave.

CONCLUSIONS

Incidence rate of COVID-19 was not associated with access to green space, but to the socio-demographic variables; income, population density, and life expectancy. Access to green space is equally distributed among districts in Oslo which may explain our findings.

The public health co-benefits of strategies consistent with net-zero emissions: a systematic review

Moving towards net-zero emission societies is projected to provide human health co-benefits. However, the magnitude of these co-benefits is poorly documented and might be context specific. Synthesising the evidence on these co-benefits could enhance the engagement of decision makers and populations in climate mitigation actions. We performed database searches of PubMed, Web of Science, and Scopus for studies published between database inception and Jan 1, 2024, identifying 3976 papers. Of these, 58 quantitative studies met our inclusion criteria and were included in this systematic review. These 58 papers explored 125 net-zero emission scenarios and considered various pathways by which climate policies can affect human health. Pathways addressing air quality, physical activity, and dietary changes found substantial health co-benefits, with a median mortality reduction of 1·5%. National or sub-national studies showed that net-zero policies would yield substantial local air quality benefits, independently of the actions taken in neighbouring countries. However, these co-benefits varied with explored emission sector, decarbonisation levers, modelling approach, and location. Studies that included a cost-benefit analysis estimated that monetised benefits outweighed the costs of implementing climate policies. This systematic review highlights the need for a standardised framework to assess and compare health impacts of climate mitigation actions across sectors and confirms that achieving net-zero goals supports far-reaching public health policies. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Inequality in green space distribution and its association with preventable deaths across urban neighbourhoods in the UK, stratified by Index of Multiple Deprivation

BACKGROUND

This study investigated inequalities in the distribution of green space (GS) and the association between inequalities in amounts of GS and preventable deaths across urban neighbourhoods with different Index of Multiple Deprivation (IMD) scores in the UK.

METHODS

Data on preventable deaths, IMD, percentage of grassland and woodland, urban/rural, population size, and density were sourced for each of 6791 middle-layer super output areas (MSOAs) in England, 410 MSOAs in Wales, 1279 intermediate zones (IZs) in Scotland, and 890 super output areas (SOAs) in Northern Ireland (NI). While appreciating the potential for ecological fallacy we related area-based measures of deprivation to deaths. Concentration curves, Lorenz dominance tests, and negative binomial regression models were used to analyse the data.

RESULTS

In urban areas of England, Scotland, and NI, the percentage of grassland was significantly lower among the more deprived neighbourhoods (Lorenz test, p<0.0001). In England, a 1% increase in grassland area was associated with a 37% reduction in annual preventable deaths among the most deprived urban MSOAs (incidence rate ratio (IRR) 0.63, 95% CI 0.52 to 0.76). In NI and Scotland, a 1% increase in grassland area was associated with a 37% (IRR 0.63, 95% CI 0.43 to 0.91) and 41% (IRR 0.59, 95% CI 0.42 to 0.81) reduction in 5-year accumulated preventable deaths in the most deprived urban SOAs/IZs, respectively.

CONCLUSIONS

Results suggest that investment in GS in urban areas may be an important public health prevention strategy. There is evidence that investments in the most deprived urban neighbourhoods where the highest inequality currently exists would see the largest effect on preventable deaths.

Ambient air pollution, urban green space and childhood overweight and obesity: A health impact assessment for Barcelona, Spain

BACKGROUND

The burden of childhood overweight and obesity attributable to ambient air pollution and a lack of urban green spaces (UGS) remains unknown. This study aimed to estimate the attributable cases of childhood overweight and obesity due to air pollution and insufficient UGS exposure in Barcelona, Spain.

METHODS

We applied a quantitative health impact assessment approach. We collected childhood overweight and obesity prevalence levels and exposure data from 69 spatial basic health zones in Barcelona. We estimated particulate matter (PM2.5) and nitrogen dioxide (NO2) levels using land use regression models, normalized difference vegetation index (NDVI) levels using remote sensing and percentage of green area (%GA) using land use. We estimated relative risks, population attributable fractions, and preventable overweight/obesity cases in children under following scenarios: Compliance of World Health Organization (WHO) air quality guidelines (AQGs) for (1) PM2.5 and (2) NO2; achieving (3) city-target NDVI levels and (4) 25% green area (%GA) recommendations. The analyses were stratified by socioeconomic deprivation index (in quintiles). Uncertainty was quantified using Monte Carlos simulations.

RESULTS

Compliance of WHO AQGs could prevent 0.4% [253 (95%CI, -604; 1086)] and 4.2% [3000 (95%CI, 1009; 4943)] of childhood overweight/obesity cases due to excess PM2.5 and NO2 levels in Barcelona, respectively. Compliance of NDVI and %GA targeted levels could prevent 6% [4094 (95%CI, 1698; 6379)] and 10% [6853 (95%CI, 1440; 12779)] of childhood overweight/obesity cases respectively. The preventable burdens of childhood overweight/obesity cases were slightly higher in middle-class socioeconomic areas due to the higher adverse exposure levels at baseline (high air pollution, less UGS).

DISCUSSION

Compliance with WHO AQGs and achieving UGS targets can reduce childhood overweight and obesity levels in Barcelona, and potentially in other locations as well. This underscores the need for policies that foster healthier urban environments of high environmental quality in order to protect child health.

Identifying the healthy places to live in Australia with a new environmental quality health index

BACKGROUND

Existing environmental quality indices often fail to account for the varying health impacts of different exposures and exclude socio-economic status indicators (SES).

OBJECTIVES

To develop and validate a comprehensive Environmental Quality Health Index (EQHI) that integrates multiple environmental exposures and SES to assess mortality risks across Australia.

METHODS

We combined all-cause, cardiovascular, and respiratory mortality data (2016-2019) from 2,180 Statistical Areas Level 2 with annual mean values of 12 environmental exposures, including PM2.5, ozone, temperature, humidity, normalized difference vegetation index, night light, road and building density, and socioeconomic status. Exposure-mortality relationships were estimated using a spatial age-period-cohort model, and EQHIs (scored 0-100, with higher values indicating better conditions) were constructed. Validation was performed using K-fold cross-validation and spatial regression models.

RESULTS

Validation showed strong model performance (R-squared = 83.53 %, 75.55 %, and 52.44 % for EQHI-all cause, EQHI-CVD, and EQHI-Resp). Each interquartile increase in EQHI-all cause reduced all-cause mortality risk by 10 %, with similar reductions for cardiovascular and respiratory mortality. Geographically, EQHIs were higher in south, east, and southeast coastal regions. From 2016 to 2019, SA2s with the highest EQHI (>75) decreased from 27.1 % to 21.1 %. The population weighted EQHI was highest in Hobart and lowest in Darwin.

CONCLUSIONS

We established, to our knowledge, the first tool to quantify and communicate environmental health risks using three types of mortality data and 12 environmental factors. This EQHI provides a robust framework to assess environmental health risks and guide targeted interventions. Our methodology can be adapted globally to standardize risk evaluation.

Greenness and averted mortality in 390 cities in China (2000-2020)

Background

China's growth over recent decades rapidly transformed the urban landscapes. Green spaces provide numerous health benefits including acting as nature-based solutions for climate change risks. Our study aims to track greenness trends in urban areas in China and quantify the health impact of greenness on adult mortality.

Methods

In China, we mapped the urban human population distribution aged 20 and above with a 1 km grid (30 arc-second) and used satellite-based remote sensing to measure green space over time to create population-weighted normalized difference vegetation index (NDVI). We tracked changes in greenness in the urban area over time and created a spatial-temporal map. Based on counterfactual scenarios, we calculated averted deaths attributed to NDVI changes from 2000 to 2020.

Findings

We analyzed and mapped 390 cities or urban areas in China, covering an urban population of nearly 500 million. We found population-weighted NDVI exhibiting an overall increase from 2000 to 2020 for most cities. Our analysis calculated urban areas that experienced decrease in urban NDVI from 2000 to 2010 could have had an estimated 9951 additional deaths annually (95% CI: 3346-18,106), while increase in NDVI from 2010 to 2020 could have averted an estimated 37,653 deaths annually (95% CI: 26,327-60,135). If the NDVI were increased to the target level in 2000 and 2010, the number of deaths would be reduced by 110,976 (95% CI: 82,010-171,561) and 118,330 (95% CI: 87,362-183,283), respectively.

Interpretation

Greenness has increased in most urban in China since 2000. Considering the ongoing impacts of climate change and urbanization, sustained efforts in greenness management could serve as an effective resilience factor for protecting population health.

Funding

Natural Science Foundation of Beijing (IS23105), National Natural Science Foundation of China (82250610230, 72061137004), World Health Organization (2024/1463606-0), Research Fund Vanke School of Public HealthTsinghua University (2024JC002).

Single- and two-pollutant concentration-response functions for PM2.5 and NO2 for quantifying mortality burden in health impact assessments

OBJECTIVE

Health Impact Assessments (HIAs) for air pollutant mixtures are challenging because risk estimates are primarily derived from single-pollutant models. Combining risk estimates from multiple pollutants requires new approaches, as a simple addition of single pollutant risk estimates from correlated air pollutants may result in double counting. We investigated approaches applying concentration-response functions (CRFs) from single- and two-pollutant models in HIAs, focusing on long-term exposure to particulate matter with a diameter less than 2.5 μm (PM2.5) and nitrogen dioxide (NO2) and their associations with all-cause mortality.

METHODS

A systematic literature search of MEDLINE and EMBASE identified cohort studies employing single- and two-pollutant models of long-term exposure to PM2.5 and NO2 with all-cause mortality. Pooled CRFs were calculated through random-effects meta-analyses of risk estimates from single- and two-pollutant models. Coefficient differences were calculated by comparing single- and two-pollutant model estimates. Four approaches to estimating population-attributable fractions (PAFs) were compared: PM2.5 or NO2 single-pollutant models to represent the mixture, the sum of single-pollutant models, the sum of two-pollutant models and the sum of single-pollutant models from a larger body of evidence adjusted by coefficient difference.

RESULTS

Seventeen papers reported both single and two-pollutant estimates. Pooled hazard ratios (HRs) for mortality from single- and two-pollutant models were 1.053 (95% confidence interval: 1.034-1.071) and 1.035 (1.014-1.057), respectively, for a 5 μg/m3 increase in PM2.5. HRs for a 10 μg/m3 increase in NO2 were 1.032 (1.014-1.049) and 1.024 (1.000-1.049) for single- and two-pollutant models, respectively. The average coefficient difference between single- and two-pollutant models was 0.017 for PM2.5 and 0.007 for NO2. Combined PAFs for the PM2.5-NO2 mixture using joint HRs from single- and two-pollutant model CRFs were 0.09 and 0.06, respectively.

CONCLUSION

Utilizing CRFs from two-pollutant models or applying the coefficient difference to a more extensive evidence base seems to mitigate the potential overestimation of mixture health impacts from adding single-pollutant CRFs.

Sleep problems mediate the association between outdoor nighttime light and symptoms of depression and anxiety: A cross-sectional, multi-city study in Bulgaria

BACKGROUND

Nighttime light is a growing anthropogenic health threat, particularly in urban areas. Limited evidence suggests that exposure to outdoor artificial light at night (ALAN) may be associated with people's mental health by disrupting sleep-wake cycles.

AIMS

We assessed 1) the association between ALAN exposure and adults' symptoms of depression and anxiety, 2) whether the association was modified by sex, age, and income, and 3) the mediating role of sleep problems.

METHODS

We obtained cross-sectional data from 4,068 adults from the five largest Bulgarian cities. Depression and anxiety symptoms were measured using the 4-item Patient Health Questionnaire (PHQ-4). Sleep problems were self-reported based on three items. Outdoor ALAN at residential addresses was assessed using annual radiance levels obtained from satellite imagery. Regression models were adjusted for person-level characteristics, green space, and nitrogen dioxide (NO2). We also assessed effect modification by sex, age, and income. Using mediation analyses, we tested sleep problems as a mediator of the ALAN-PHQ-4 association.

RESULTS

Greater ALAN exposure in the fully adjusted model was marginally associated with higher PHQ-4 scores. We observed no effect modification. The mediator, sleep problems, was also positively associated with ALAN. The mediation of sleep problems was significantly positive. While the direct association was null, the total ALAN association was marginally and positively associated with PHQ-4 scores.

CONCLUSIONS

Our findings suggest a positive association between outdoor nighttime light pollution and mental health. Poor sleep quality is a possible pathway relating ALAN exposure to mental health. Considering the increasing ubiquity and intensity of urban nighttime illumination, light pollution-reducing policies may provide significant health benefits for urban populations.

Health effects of greenspace morphology: Large, irregular-shaped, well-connected, and close-clustered greenspaces may reduce mortality risks, especially for neighborhoods with higher aging levels

The healthcare burden has intensified with urbanization and aging populations in many global cities. While the health effects of urban greenspaces have been well documented, little is known about the associations between greenspace morphological features and health, especially in a high-density city with significant aging populations. Drawing on land use data with 10-m resolution, we assessed seven greenspace morphological metrics in terms of size (the percentage of greenspace, the largest pixel index, the average greenspace area), fragmentation (the patch density), shape (the average weighted shape index), connectedness (the cohesion index), and proximity (the aggregation index). We further conducted an ecological study to examine their associations with all-cause and three cause-specific (cardiovascular disease, respiratory disease, and cancer) mortality. Results from the negative binomial regression models revealed protective effects of five greenspace morphology metrics, including the percentage of greenspace, the largest pixel index, the average weighted shape index, the cohesion index, and the aggregation index, on mortality. The shape index showed the greatest effects, with every 1 Standard Deviation (SD) increase in the shape index linked to a reduction of 22.1% (95% CI: 22.0%-31.0%) in all-cause mortality, 22.1% (12.2%-30.8%) in mortality from cardiovascular diseases, 25.0% (14.0%-34.6%) in mortality from respiratory diseases, and 22.0% (12.3%-30.6%) in mortality from cancers. Moreover, stratified analyses revealed that the health effects of the cohesion index and the aggregation index were significantly more pronounced in neighborhoods with higher aging levels. Our findings highlight the significance of greenspace morphology features, beyond greenspace quantity, in improving residents' health, particularly for societies with high aging populations.

Chronic impacts of natural infrastructure on the physical and psychological health of university students during and after COVID-19: a case study of Chengdu, China

Introduction

The COVID-19 pandemic has underscored the health benefits of green spaces, yet research on how specific elements of natural infrastructure affect well-being during the pandemic has been limited.

Methods

This study, conducted at Sichuan Agricultural University with 300 students in 2022, investigated how urban natural infrastructure impacts physical and psychological well-being during the pandemic. Different aspects of natural infrastructure, such as thermal comfort, air quality (negative ion concentration), and noise and light levels, varied in their positive effects on students' health.

Results

The findings revealed that 65.6% of university students felt reduced stress when engaging with outdoor spaces, and 72.8% of them renewed recognized the therapeutic value of nature.

Discussion

The study emphasizes the importance of incorporating natural elements into urban planning to enhance outdoor activity and well-being, especially in post-pandemic settings. Recommendations are provided for future urban design to address the therapeutic needs of specific populations.

Commentary: A road map for future data-driven urban planning and environmental health research

Recent advances in data science and urban environmental health research utilise large-scale databases (100s-1000s of cities) to explore the complex interplay of urban characteristics such as city form and size, climate, mobility, exposure, and environmental health impacts. Cities are still hotspots of air pollution and noise, suffer urban heat island effects and lack of green space, which leads to disease and mortality burdens preventable with better knowledge. Better understanding through harmonising and analysing data in large numbers of cities is essential to identifying the most effective means of disease prevention and understanding context dependencies important for policy.

The mortality impacts of greening Italy

Green spaces have been shown to be beneficial to humans, but quantifying these benefits is a challenge for epidemiology. In this health impact assessment study, we exploit satellites to estimate for the whole of Italy the number of deaths that could be prevented in the 49 million adult population by greening residential areas. The exposure was assessed by calculating the normalized difference vegetation index at 10-m resolution within a 300-m distance from homes in 7904 municipalities. In this study we estimate, by achieving nationwide the level of residential greenness currently reached by the 25% of the population, a total of 28,433 (95% confidence interval: 21,400-42,350) preventable deaths and 279,324 (210,247-415,980) preventable years of life lost in Italy in 2022, representing the 5% of the total mortality burden. More green means fewer deaths, thus strong action is needed to increase the amount and accessibility of green spaces in all human settlements.

Residential greenspace and COVID-19 morbidity and mortality: A nationwide cohort study in Denmark

BACKGROUND

Identifying modifiable environmental determinants of health is important for improving the resilience of populations to infectious disease. We examined the association between residential greenspace and COVID-19 morbidity and mortality using a Danish Nationwide Cohort, and estimate the potential health benefits of greening initiatives.

METHODS

We followed all Danish adults aged 50 or older (N = 2,111,233) using the Danish National COVID-19 Surveillance System for COVID-19 incident infection, hospitalization and mortality, from 1 March 2020 to 26 April 2021. Greenspace was characterized using Normalized Difference Vegetation Index (NDVI) at 300x300m grid-cell level and linked to residential addresses. We used Cox regression to assess the association between greenspace and COVID-19 morbidity and mortality, and applied effect modification analyses to identify the most susceptible groups by sociodemographic status and comorbidity. Following a health impact assessment (HIA), we also estimated the preventable burden of disease attributable to greenspace under different counterfactual scenarios.

RESULTS

During an average of 14 months follow-up, 62,880 participants were infected with SARS-CoV-2, of whom 8,759 were hospitalized, and 2,382 died, with COVID-19. We observed a negative association between residential greenspace and COVID-19 morbidity and mortality, with hazard ratios (95 % confidence interval) of 0.98 (0.97, 0.99) for SARS-CoV-2 infection, 0.97 (0.94, 0.99) for COVID-19 hospitalization, and 0.96 (0.91, 1.01) for COVID-19 mortality per interquartile range (0.08 unit) increase in NDVI. Stronger associations were observed in the elderly, those with lower SES, and major chronic diseases than their corresponding groups. Regarding the HIA, we estimated that increasing greenspace around residences up to WHO recommended levels would have prevented 8-14 % of COVID-19 events during the first 14 months, with the largest benefits among those with the lowest income, education, or without employment.

CONCLUSION

Greening initiatives in urban areas could help prevent COVID-19, and likely other infectious disease, with socially disadvantaged groups benefiting most.

The environmental health citizen interview tool: towards an inclusive qualitative environmental wellbeing approach in support of planetary health

Background

Nature-based Solutions (NbS) are vital for addressing climate change and biodiversity loss, yet their benefits are often unequally distributed. This study introduces the Environmental Health Citizen Interview Tool, aiming to inclusively capture diverse perspectives on environmental wellbeing using qualitative research methods. The principles of epistemic justice and planetary health are central to its development.

Methods

The Environmental Health Citizen Interview Tool was developed as a qualitative tool, incorporating a simple visualization scoring system for responses. Six environmental health determinants were selected, with in-depth open-ended follow-up questions. Content validation involved transdisciplinary expert consultation. A guidebook for using the tool was also developed.

Findings

The tool offers a comprehensive approach to inquire environmental wellbeing, accommodating diverse perspectives through in-depth inquiries. Limitations include the need for further validation and testing.

Interpretation

The Environmental Health Citizen Interview Tool provides a practical framework for inclusive assessment of environmental wellbeing, aligned with planetary health and epistemic justice principles. Its application should be complemented by quantitative environmental monitoring such as air quality and be contextualized by local researchers for reliability and relevance. Future research should focus on refining the tool and exploring its utility in diverse settings to inform equitable local policy interventions.

Short-term ozone exposure on stroke mortality and mitigation by greenness in rural and urban areas of Shandong Province, China

BACKGROUND

Short-term exposure to ozone (O3) has been associated with higher stroke mortality, but it is unclear whether this association differs between urban and rural areas. The study aimed to compare the association between short-term exposure to O3 and ischaemic and haemorrhagic stroke mortality across rural and urban areas and further investigate the potential impacts of modifiers, such as greenness, on this association.

METHODS

A multi-county time-series analysis was carried out in 19 counties of Shandong Province from 2013 to 2019. First, we employed generalized additive models (GAMs) to assess the effects of O3 on stroke mortality in each county. We performed random-effects meta-analyses to pool estimates to counties and compare differences in rural and urban areas. Furthermore, a meta-regression model was utilized to assess the moderating effects of county-level features.

RESULTS

Short-term O3 exposure was found to be associated with increased mortality for both stroke subtypes. For each 10-µg/m3 (lag0-3) rise in O3, ischaemic stroke mortality rose by 1.472% in rural areas and 1.279% in urban areas. For each 0.1-unit increase in the Enhanced Vegetation Index (EVI) per county, the ischaemic stroke mortality caused by a 10-µg/m3 rise in O3 decreased by 0.60% overall and 1.50% in urban areas.

CONCLUSIONS

Our findings add to the evidence that short-term O3 exposure increases ischaemic and haemorrhagic stroke mortality and has adverse effects in urban and rural areas. However, improving greenness levels may contribute to mitigating the detrimental effects of O3 on ischaemic stroke mortality.

Extensive inequality of residential greenspace exposure within urban areas in China

Ensuring residents' equal access to high quality urban greenspace is vital for urban environmental justice and sustainable urban development. However, most previous studies have mainly focused on greenspace quantity, overlooking its quality. Moreover, the national-level spatial distribution pattern of residential greenspace exposure (RGE) within urban areas remains unclear. Here, we have improved the existing RGE assessment framework by integrating both the quality and quantity of urban greenspace to evaluate RGE and its associated inequality across 119,692 blocks in 334 Chinese cities in 2020. We find that the spatial distribution pattern of RGE varies with urban size. Large cities exhibit a distinct clustering of low RGE in their central areas, whereas small cities tend to show a pronounced clustering of high RGE in the central areas. RGE in Chinese cities indicates extensive inequality, as the average RGE of high-exposed people is nearly four times greater than that of low-exposed people. Moreover, residents in larger cities are more prone to experiencing greater inequalities compared to those in smaller cities. We also find that the landscape metrics (i.e., connectance index and mean Euclidean nearest-neighbor distance) of greenspace possess a strong explanatory power (R2 = 0.431) for the observed inequality. Our study underscores the importance of optimizing the landscape structure of urban greenspace and enhancing equality in the quality of greenspace. These findings provide novel insights for urban greenspace planning and promoting urban environmental justice.

Injuries and deaths due to tree failure in The Netherlands: analysis of observational data from 1998-2021

Urban and roadside trees contribute to health and resilience. However, when trees or branches fall, it can cause injuries or deaths. This study examined trends and variations of injuries and deaths due to tree failure in The Netherlands from 1998 to 2021, considering urban-rural location, sex, age and traffic mode. This study is the first to describe long-term trends in injuries and deaths due to tree failure from 1998-2021. The standardised rate of injuries per 1,000,000 population increased from 0.14 (SE 0.10) in 1998 to 0.91 (SE 0.21) in 2021, with an annual percentage increase of 5.3% (p = 0.002). The data shows a strong increase for rural areas, contrary to urban ones. The annual percentage increase in rural areas was 13.2% (p < 0.001) while injuries in urban areas increased with 3.0% (p = 0.026), which revealed large urban-rural disparities. A trend was absent in the frequency of deaths. More attention needs to be given to investigating causes, drivers and stressors associated with tree failure-related injuries. In particular, efforts should be made to reduce the prevalence in rural areas. The increase in injuries over time makes it necessary to create awareness and share knowledge among residents and local governments about tree failure risks.

Exploring the nexus of urban form, transport, environment and health in large-scale urban studies: A state-of-the-art scoping review

BACKGROUND

As the world becomes increasingly urbanised, there is recognition that public and planetary health relies upon a ubiquitous transition to sustainable cities. Disentanglement of the complex pathways of urban design, environmental exposures, and health, and the magnitude of these associations, remains a challenge. A state-of-the-art account of large-scale urban health studies is required to shape future research priorities and equity- and evidence-informed policies.

OBJECTIVES

The purpose of this review was to synthesise evidence from large-scale urban studies focused on the interaction between urban form, transport, environmental exposures, and health. This review sought to determine common methodologies applied, limitations, and future opportunities for improved research practice.

METHODS

Based on a literature search, 2958 articles were reviewed that covered three themes of: urban form; urban environmental health; and urban indicators. Studies were prioritised for inclusion that analysed at least 90 cities to ensure broad geographic representation and generalisability. Of the initially identified studies, following expert consultation and exclusion criteria, 66 were included.

RESULTS

The complexity of the urban ecosystem on health was evidenced from the context dependent effects of urban form variables on environmental exposures and health. Compact city designs were generally advantageous for reducing harmful environmental exposure and promoting health, with some exceptions. Methodological heterogeneity was indicative of key urban research challenges; notable limitations included exposure and health data at varied spatial scales and resolutions, limited availability of local-level sociodemographic data, and the lack of consensus on robust methodologies that encompass best research practice.

CONCLUSION

Future urban environmental health research for evidence-informed urban planning and policies requires a multi-faceted approach. Advances in geospatial and AI-driven techniques and urban indicators offer promising developments; however, there remains a wider call for increased data availability at local-levels, transparent and robust methodologies of large-scale urban studies, and greater exploration of urban health vulnerabilities and inequities.

The use of Enhanced Vegetation Index for assessing access to different types of green space in epidemiological studies

BACKGROUND

Exposure to green space can protect against poor health through a variety of mechanisms. However, there is heterogeneity in methodological approaches to exposure assessments which makes creating effective policy recommendations challenging.

OBJECTIVE

Critically evaluate the use of a satellite-derived exposure metric, the Enhanced Vegetation Index (EVI), for assessing access to different types of green space in epidemiological studies.

METHODS

We used Landsat 5-8 (30 m resolution) to calculate average EVI for a 300 m radius surrounding 1.4 million households in Wales, UK for 2018. We calculated two additional measures using topographic vector data to represent access to green spaces within 300 m of household locations. The two topographic vector-based measures were total green space area stratified by type and average private garden size. We used linear regression models to test whether EVI could discriminate between publicly accessible and private green space and Pearson correlation to test associations between EVI and green space types.

RESULTS

Mean EVI for a 300 m radius surrounding households in Wales was 0.28 (IQR = 0.12). Total green space area and average private garden size were significantly positively associated with corresponding EVI measures (β = < 0.0001, 95% CI: 0.0000, 0.0000; β = 0.0001, 95% CI: 0.0001, 0.0001 respectively). In urban areas, as average garden size increases by 1 m2, EVI increases by 0.0002. Therefore, in urban areas, to see a 0.1 unit increase in EVI index score, garden size would need to increase by 500 m2. The very small β values represent no 'measurable real-world' associations. When stratified by type, we observed no strong associations between greenspace and EVI.

IMPACT

It is a widely implemented assumption in epidiological studies that an increase in EVI is equivalent to an increase in greenness and/or green space. We used linear regression models to test associations between EVI and potential sources of green reflectance at a neighbourhood level using satellite imagery from 2018. We compared EVI measures with a 'gold standard' vector-based dataset that defines publicly accessible and private green spaces. We found that EVI should be interpreted with care as a greater EVI score does not necessarily mean greater access to publicly available green spaces in the hyperlocal environment.

The effects of fine particulate matter, solid fuel use and greenness on the risks of diabetes in middle-aged and older Chinese

BACKGROUND

Previous studies provided clues that environmental factors were closely related to diabetes incidence. However, the evidence from high-quality and large cohort studies about the effects of PM2.5, solid fuel use and greenness on the development of diabetes among middle-aged and older adults in China was scarce.

OBJECTIVE

To separately investigate the independent effects of PM2.5, solid fuel use and greenness on the development of diabetes among middle-aged and older adults.

METHODS

A total of 9242 participants were involved in this study extracted from the China Health and Retirement Longitudinal Study. Time-varying Cox regression was applied to detect the association of diabetes with PM2.5, solid fuel use and greenness, separately. The potential interactive effect of air pollution and greenness were explored using the relative excess risk due to interaction (RERI).

RESULTS

Per 10 μg/m3 increases in PM2.5 were associated with 6.0% (95% CI: 1.9, 10.2) increasing risks of diabetes incidence. Females seemed to be more susceptible to PM2.5. However, the effects of solid fuel use only existed in older and lower BMI populations, with hazard ratios (HRs) of 1.404 (1.116, 1.766) and 1.346 (1.057, 1.715), respectively. In addition, exposure to high-level greenness might reduce the risks of developing diabetes [HR = 0.801 (0.687, 0.934)]. Weak evidence of the interaction effect of PM2.5/solid fuel use and greenness on diabetes was found.

SIGNIFICANCE

Both PM2.5 and solid fuel use were associated with the increasing incidence of diabetes. In addition, high-level greenness might be a beneficial environmental factor for reducing the risks of developing diabetes. All in all, our findings might provide valuable references for public health apartments to formulate very fruitful policies to reduce the burden of diabetes.

IMPACT STATEMENT

Both PM2.5 and solid fuel use were associated with the increasing incidence of diabetes while high-level greenness was not, which might provide valuable references for public health apartments to make policies.

Road traffic noise pollution and prevalence of ischemic heart disease: modelling potential association and abatement strategies in noise-exposed areas

In many developing countries with surging vehicular traffic and inadequate traffic management, excessive road traffic noise exposure poses substantial health concerns, linked to increased stress, insomnia and other metabolic disorders. This study aims to assess the linkage between sociodemographic factors, traffic noise levels in residential areas and health effects using a cross-sectional study analyzing respondents' perceptions and reports. Noise levels were measured at 57 locations in Srinagar, India, using noise level meter. Sound PLAN software was employed to generate noise contour maps, enabling the visualization of noise monitoring locations and facilitating the assessment of noise levels along routes in proximity to residential areas. Correlation analysis showed a strong linear relationship between field-measured and modelled noise (r2 = 0.88). Further, a questionnaire-based survey was carried out near the sampling points to evaluate the association of ischemic heart disease with traffic noise. Residents exposed to noise levels (Lden > 60 dB(A)) were found to have a 2.24 times higher odds ratio. Compared to females, males reported a 16% higher prevalence of the disease. Multi-faceted policy strategies involving noise mapping initiatives, source noise standards, traffic flow urban mobility optimization, smart city initiatives and stringent litigatory measures could significantly reduce its detrimental impact on public health. Finally, this study envisions a region-specific strong regulatory framework for integrating noise pollution mitigation strategies into the public health action plans of developing nations.

Comprehensive evaluation of global health cities development levels

Introduction

How to scientifically assess the health status of cities and effectively assist in formulating policies and planning for health city development remains a profound challenge in building a global "health community."

Methods

This study employs the Building Research Establishment's International Healthy Cities Index (BRE HCI), encompassing ten environmental categories and fifty-eight indicators, to guide and support the scientific development of healthy cities. The entropy weight-TOPSIS method and the rank sum ratio (RSR) method were applied to comprehensively rank and categorize the health development levels of fifteen global cities. Furthermore, through cluster analysis, this research identifies universal and unique indicators that influence the development of healthy cities.

Results

The results indicate that: (1) Within the scope of 58 evaluation indicators, the precedence in weight allocation is accorded to the kilometres of bicycle paths and lanes per 100,000 population (0.068), succeeded by m2 of public indoor recreation space per capita (0.047), and kilometres of bicycle paths and lanes per 100,000 population (0.042). (2) Among the ten environmental categories, the top three in terms of weight ranking are transport (0.239), leisure and recreation (0.172), and resilience (0.125). Significant disparities exist between different cities and environmental categories, with the issue of uneven health development within cities being particularly prominent. (3) The study categorizes the development levels of healthy cities into three tiers based on composite scores: it classifies Singapore, Shanghai, and Amsterdam at an excellent level; places Dubai and Johannesburg at a comparatively poor level; and situates the remaining ten cities at a moderate level. (4) The analysis identifies 53 international common indicators and 5 characteristic indicators from the 58 indicators based on the significance of the clustering analysis (p < 0.05).

Discussion

The study proposes four strategic recommendations based on these findings: establishing a comprehensive policy assurance system, refining urban spatial planning, expanding avenues for multi-party participation, and augmenting distinctive health indicators. These measures aim to narrow the developmental disparities between cities and contribute to healthy global cities' balanced and sustainable growth. However, due to existing limitations in sample selection, research methodology application, and the control of potential confounding variables, further in-depth studies are required in the future.

The impact of urban configuration types on urban heat islands, air pollution, CO2 emissions, and mortality in Europe: a data science approach

BACKGROUND

The world is becoming increasingly urbanised. As cities around the world continue to grow, it is important for urban planners and policy makers to understand how different urban configuration patterns affect the environment and human health. However, previous studies have provided mixed findings. We aimed to identify European urban configuration types, on the basis of the local climate zones categories and street design variables from Open Street Map, and evaluate their association with motorised traffic flows, surface urban heat island (SUHI) intensities, tropospheric NO2, CO2 per person emissions, and age-standardised mortality.

METHODS

We considered 946 European cities from 31 countries for the analysis defined in the 2018 Urban Audit database, of which 919 European cities were analysed. Data were collected at a 250 m × 250 m grid cell resolution. We divided all cities into five concentric rings based on the Burgess concentric urban planning model and calculated the mean values of all variables for each ring. First, to identify distinct urban configuration types, we applied the Uniform Manifold Approximation and Projection for Dimension Reduction method, followed by the k-means clustering algorithm. Next, statistical differences in exposures (including SUHI) and mortality between the resulting urban configuration types were evaluated using a Kruskal-Wallis test followed by a post-hoc Dunn's test.

FINDINGS

We identified four distinct urban configuration types characterising European cities: compact high density (n=246), open low-rise medium density (n=245), open low-rise low density (n=261), and green low density (n=167). Compact high density cities were a small size, had high population densities, and a low availability of natural areas. In contrast, green low density cities were a large size, had low population densities, and a high availability of natural areas and cycleways. The open low-rise medium and low density cities were a small to medium size with medium to low population densities and low to moderate availability of green areas. Motorised traffic flows and NO2 exposure were significantly higher in compact high density and open low-rise medium density cities when compared with green low density and open low-rise low density cities. Additionally, green low density cities had a significantly lower SUHI effect compared with all other urban configuration types. Per person CO2 emissions were significantly lower in compact high density cities compared with green low density cities. Lastly, green low density cities had significantly lower mortality rates when compared with all other urban configuration types.

INTERPRETATION

Our findings indicate that, although the compact city model is more sustainable, European compact cities still face challenges related to poor environmental quality and health. Our results have notable implications for urban and transport planning policies in Europe and contribute to the ongoing discussion on which city models can bring the greatest benefits for the environment, climate, and health.

FUNDING

Spanish Ministry of Science and Innovation, State Research Agency, Generalitat de Catalunya, Centro de Investigación Biomédica en red Epidemiología y Salud Pública, and Urban Burden of Disease Estimation for Policy Making as a Horizon Europe project.

The Superblock model: A review of an innovative urban model for sustainability, liveability, health and well-being

INTRODUCTION

Current urban and transport planning practices have significant negative health, environmental, social and economic impacts in most cities. New urban development models and policies are needed to reduce these negative impacts. The Superblock model is one such innovative urban model that can significantly reduce these negative impacts through reshaping public spaces into more diverse uses such as increase in green space, infrastructure supporting social contacts and physical activity, and through prioritization of active mobility and public transport, thereby reducing air pollution, noise and urban heat island effects. This paper reviews key aspects of the Superblock model, its implementation and initial evaluations in Barcelona and the potential international uptake of the model in Europe and globally, focusing on environmental, climate, lifestyle, liveability and health aspects.

METHODS

We used a narrative meta-review approach and PubMed and Google scholar databases were searched using specific terms.

RESULTS

The implementation of the Super block model in Barcelona is slow, but with initial improvement in, for example, environmental, lifestyle, liveability and health indicators, although not so consistently. When applied on a large scale, the implementation of the Superblock model is not only likely to result in better environmental conditions, health and wellbeing, but can also contribute to the fight against the climate crisis. There is a need for further expansion of the program and further evaluation of its impacts and answers to related concerns, such as environmental equity and gentrification, traffic and related environmental exposure displacement. The implementation of the Superblock model gained a growing international reputation and variations of it are being planned or implemented in cities worldwide. Initial modelling exercises showed that it could be implemented in large parts of many cities.

CONCLUSION

The Superblock model is an innovative urban model that addresses environmental, climate, liveability and health concerns in cities. Adapted versions of the Barcelona Superblock model are being implemented in cities around Europe and further implementation, monitoring and evaluation are encouraged. The Superblock model can be considered an important public health intervention that will reduce mortality and morbidity and generate cost savings for health and other sectors.

Greenness, air pollution, and temperature exposure effects in predicting premature mortality and morbidity: A small-area study using spatial random forest model

BACKGROUND

Although studies have provided negative impacts of air pollution, heat or cold exposure on mortality and morbidity, and positive effects of increased greenness on reducing them, a few studies have focused on exploring combined and synergetic effects of these exposures in predicting these health outcomes, and most had ignored the spatial autocorrelation in analyzing their health effects. This study aims to investigate the health effects of air pollution, greenness, and temperature exposure on premature mortality and morbidity within a spatial machine-learning modeling framework.

METHODS

Years of potential life lost reflecting premature mortality and comparative illness and disability ratio reflecting chronic morbidity from 1673 small areas covering Greater Manchester for the year 2008-2013 obtained. Average annual levels of NO2 concentration, normalized difference vegetation index (NDVI) representing greenness, and annual average air temperature were utilized to assess exposure in each area. These exposures were linked to health outcomes using non-spatial and spatial random forest (RF) models while accounting for spatial autocorrelation.

RESULTS

Spatial-RF models provided the best predictive accuracy when accounted for spatial autocorrelation. Among the exposures considered, air pollution emerged as the most influential in predicting mortality and morbidity, followed by NDVI and temperature exposure. Nonlinear exposure-response relations were observed, and interactions between exposures illustrated specific ranges or sweet and sour spots of exposure thresholds where combined effects either exacerbate or moderate health conditions.

CONCLUSION

Air pollution exposure had a greater negative impact on health compared to greenness and temperature exposure. Combined exposure effects may indicate the highest influence of premature mortality and morbidity burden.

Green space exposure and blood DNA methylation at birth and in childhood - A multi-cohort study

Green space exposure has been associated with improved mental, physical and general health. However, the underlying biological mechanisms remain largely unknown. The aim of this study was to investigate the association between green space exposure and cord and child blood DNA methylation. Data from eight European birth cohorts with a total of 2,988 newborns and 1,849 children were used. Two indicators of residential green space exposure were assessed: (i) surrounding greenness (satellite-based Normalized Difference Vegetation Index (NDVI) in buffers of 100 m and 300 m) and (ii) proximity to green space (having a green space ≥ 5,000 m2 within a distance of 300 m). For these indicators we assessed two exposure windows: (i) pregnancy, and (ii) the period from pregnancy to child blood DNA methylation assessment, named as cumulative exposure. DNA methylation was measured with the Illumina 450K or EPIC arrays. To identify differentially methylated positions (DMPs) we fitted robust linear regression models between pregnancy green space exposure and cord blood DNA methylation and between cumulative green space exposure and child blood DNA methylation. Two sensitivity analyses were conducted: (i) without adjusting for cellular composition, and (ii) adjusting for air pollution. Cohort results were combined through fixed-effect inverse variance weighted meta-analyses. Differentially methylated regions (DMRs) were identified from meta-analysed results using the Enmix-combp and DMRcate methods. There was no statistical evidence of pregnancy or cumulative exposures associating with any DMP (False Discovery Rate, FDR, p-value < 0.05). However, surrounding greenness exposure was inversely associated with four DMRs (three in cord blood and one in child blood) annotated to ADAMTS2, KCNQ1DN, SLC6A12 and SDK1 genes. Results did not change substantially in the sensitivity analyses. Overall, we found little evidence of the association between green space exposure and blood DNA methylation. Although we identified associations between surrounding greenness exposure with four DMRs, these findings require replication.

The greener the living environment, the better the health? Examining the effects of multiple green exposure metrics on physical activity and health among young students

The sedentary and less active lifestyle of modern college students has a significant impact on the physical and mental well-being of the college community. Campus Green Spaces (GSs) are crucial in promoting physical activity and improving students' health. However, previous research has focused on evaluating campuses as a whole, without considering the diverse spatial scenarios within the campus environment. Accordingly, this study focused on the young people's residential scenario in university and constructed a framework including a comprehensive set of objective and subjective GSs exposure metrics. A systematic, objective exposure assessment framework ranging from 2D (GSs areas), and 2.5D (GSs visibility) to 3D (GSs volume) was innovatively developed using spatial analysis, deep learning technology, and unmanned aerial vehicle (UAV) measurement technology. Subjective exposure metrics incorporated GSs visiting frequency, GSs visiting duration, and GSs perceived quality. Our cross-sectional study was based on 820 university students in Nanjing, China. Subjective measures of GSs exposure, physical activity, and health status were obtained through self-reported questionnaires. The Generalized Linear Model (GLM) was used to evaluate the associations between GSs exposure, physical activity, and perceived health. Physical activity and social cohesion were considered as mediators, and path analysis based on Structural Equation Modeling (SEM) was used to disentangle the mechanisms linking GSs exposure to the health status of college students. We found that (1) 2D indicator suggested significant associations with health in the 100m buffer, and the potential underlying mechanisms were: GSs area → Physical activity → Social cohesion → Physical health → Mental health; GSs area → Physical activity → Social cohesion → Mental health. (2) Subjective GSs exposure indicators were more relevant in illustrating exposure-response relationships than objective ones. This study can clarify the complex nexus and mechanisms between campus GSs, physical activity, and health, and provide a practical reference for health-oriented campus GSs planning.

Pathways linking greenspace to behavioural problems in Polish children

Background

Previous cross-sectional studies have found a beneficial relationship between greenspace and children's behaviour. Nevertheless, evidence on the mechanisms underlying this association remains scant. We examined whether the availability of greenspace was related to fewer behavioural problems in Polish children and investigated potential mechanisms.

Methods

Data were obtained from the case-control NeuroSmog study, in which children with and without attention deficit hyperactivity disorder (ADHD) were tested from October 2020 to September 2022. The analytic sample comprised 679 children aged 10-13 years. Parents reported internalizing, externalizing, and total behavioural problems using the Child Behaviour Check List (CBCL), as well as information about the presence of a domestic garden and potential mediators: greenspace perception, neighbourhood social cohesion, and physical activity. Tree and grass covers were extracted in 500 m and 1 km buffers around lifelong residences. Structural equation modelling (SEM) was used to examine the psychosocial pathways linking the greenspace metrics to behavioural problems.

Results

Greenspace was only indirectly related to fewer behavioural problems. Specifically, tree cover was related to greater levels of physical activity which, in turn, was related to fewer internalizing and total behavioural problems. Tree cover and presence of garden were related to greenspace perception which, in turn, was associated with higher neighbourhood social cohesion which, in turn, was linked to fewer behavioural problems. The patterns of associations in children without ADHD were very similar to those in the full sample except that the associations from garden to greenspace perception and from physical activity to total behavioural problems were no longer significant. The only association persisted among girls was from neighbourhood social cohesion to behavioural problems and among boys were from tree cover to physical activity and tree cover and garden to greenspace perception.

Conclusion

Trees and garden, but not grass, are linked to fewer behavioural problems through greenspace perception, neighbourhood social cohesion, and physical activity in Polish children.

Greenspaces and Health: Scoping Review of studies in Europe

Objectives

Access to greenspaces and contact with nature can promote physical activity and have positive effects on physical and mental health. This scoping literature review aims to examine current evidence linking greenspaces and (a) behaviour change, (b) health outcomes and (c) co-benefits.

Methods

This review was conducted in accordance with the PRISMA scoping review guidelines. Searches were conducted through PubMed and EMBASE databases for studies published between 2000 and March 2023 with a focus on Europe.

Results

122 scientific articles and grey literature reports were identified. Access to greenspaces is positively associated with physical and mental health, and reduced risk of all-cause mortality and some non-communicable diseases. Greenspace quality is associated with increased physical activity and reduced risk of obesity. Nature-based therapies or green prescription are effective in improving mental health outcomes and overall health. Importantly, numerous co-benefits of greenspaces are identified.

Conclusion

Increasing access to greenspaces for populations with particular attention to greenspace quality is important for co-benefits. Responsible governance and use of greenspaces are crucial to minimize public health risks and human disturbance of nature.

Exploring the spatial association between the distribution of temperature and urban morphology with green view index

Urban heat islands will occur if city neighborhoods contain insufficient green spaces to create a comfortable environment, and residents' health will be adversely affected. Current satellite imagery can only effectively identify large-scale green spaces and cannot capture street trees or potted plants within three-dimensional building spaces. In this study, we used a deep convolutional neural network semantic segmentation model on Google Street View to extract environmental features at the neighborhood level in Taipei City, Taiwan, including the green vegetation index (GVI), building view factor, and sky view factor. Monthly temperature data from 2018 to 2021 with a 0.01° spatial resolution were used. We applied a linear mixed-effects model and geographically weighted regression to explore the association between pedestrian-level green spaces and ambient temperature, controlling for seasons, land use information, and traffic volume. Their results indicated that a higher GVI was significantly associated with lower ambient temperatures and temperature differences. Locations with higher traffic flows or specific land uses, such as religious or governmental, are associated with higher ambient temperatures. In conclusion, the GVI from street-view imagery at the community level can improve the understanding of urban green spaces and evaluate their effects in association with other social and environmental indicators.

Impacts of social deprivation on mortality and protective effects of greenness exposure in Hong Kong, 1999-2018: A spatiotemporal perspective

Addressing health inequality is crucial for fostering healthy city development. However, there is a dearth of literature simultaneously investigating the effects of social deprivation and greenness exposure on mortality risks, as well as how greenness exposure may mitigate the adverse effect of social deprivation on mortality risks from a spatiotemporal perspective. Drawing on socioeconomic, remote sensing, and mortality record data, this study presents spatiotemporal patterns of social deprivation, population weighted greenness exposure, and all-cause and cause-specific mortality in Hong Kong. A Bayesian regression model was applied to investigate the impacts of social deprivation and greenness exposure on mortality and examine how socioeconomic inequalities in mortality may vary across areas with different greenness levels in Hong Kong from 1999 to 2018. We observed a decline in social deprivation (0.67-0.56), and an increase in greenness exposure (0.34-0.41) in Hong Kong during 1999-2018. Areas with high mortality gradually clustered in the Kowloon Peninsula and the northern regions of Hong Kong Island. Adverse impacts of social deprivation on all-cause mortality weakened in recent years (RR from 2009 to 2013: 1.103, 95%CI: 1.051-1.159, RR from 2014 to 2018: 1.041 95%CI: 0.950-1.139), while the protective impacts of greenness exposure consistently strengthened (RR from 1999 to 2003: 0.903, 95%CI: 0.827-0.984, RR from 2014 to 2018: 0.859, 95%CI: 0.763-0.965). Moreover, the adverse effects of social deprivation on mortality risks were found to be higher in areas with lower greenness exposure. These findings provide evidence of associations between social deprivation, greenness exposure, and mortality risks in Hong Kong over the past decades, and highlight the potential of greenness exposure to mitigate health inequalities. Our study provides valuable implications for policymakers to develop a healthy city.

Toward Heart-Healthy and Sustainable Cities: A Policy Statement From the American Heart Association

Nearly 56% of the global population lives in cities, with this number expected to increase to 6.6 billion or >70% of the world's population by 2050. Given that cardiometabolic diseases are the leading causes of morbidity and mortality in people living in urban areas, transforming cities and urban provisioning systems (or urban systems) toward health, equity, and economic productivity can enable the dual attainment of climate and health goals. Seven urban provisioning systems that provide food, energy, mobility-connectivity, housing, green infrastructure, water management, and waste management lie at the core of human health, well-being, and sustainability. These provisioning systems transcend city boundaries (eg, demand for food, water, or energy is met by transboundary supply); thus, transforming the entire system is a larger construct than local urban environments. Poorly designed urban provisioning systems are starkly evident worldwide, resulting in unprecedented exposures to adverse cardiometabolic risk factors, including limited physical activity, lack of access to heart-healthy diets, and reduced access to greenery and beneficial social interactions. Transforming urban systems with a cardiometabolic health-first approach could be accomplished through integrated spatial planning, along with addressing current gaps in key urban provisioning systems. Such an approach will help mitigate undesirable environmental exposures and improve cardiovascular and metabolic health while improving planetary health. The purposes of this American Heart Association policy statement are to present a conceptual framework, summarize the evidence base, and outline policy principles for transforming key urban provisioning systems to heart-health and sustainability outcomes.

Urban green spaces and behavioral and cognitive development in children: A health impact assessment of the Barcelona "Eixos Verds" Plan (Green Axis Plan)

BACKGROUND

Urban environments lack natural features, while nature exposure in cities has been associated with health benefits, including children's neurodevelopment. Through extensive street greening, Barcelona's Eixos Verds (Green Axis) Plan enhances safety, environment, and climate resilience. We aimed to assess the Eixos Verds Plan's potential impact on children's behavioral and cognitive development due to the increased green space expected under the Eixos Verds implementation.

METHODS

We performed a quantitative health impact assessment for Barcelona children at census-tract level (n = 1068). We assessed the Eixos Verds Plan's impact by comparing baseline green space distribution with the proposed plan, translating it into percentage green area (%GA) and Normalized Difference Vegetation Index (NDVI). By combining these exposure metrics with child-specific risk estimates and population data, we estimated potential improvements in children's behavioral and cognitive development due to full Eixos Verds implementation.

RESULTS

With the full Eixos Verds implementation, citywide, %GA increased by 6.9% (IQR: 6.4%; range: 0-23.1%) and NDVI by 0.065 (IQR: 0.083; range: 0.000-0.194). Child behavioral and cognitive development outcomes are expected to improve compared to the baseline. Based on NDVI increases, children's Total Difficulties and Hyperactivity/Inattention scores, based on the Strengths and Difficulties Questionnaire (SDQ), are projected to decrease by 5% (95% CI: 0-15%) and 6% (95% CI: 0-17%). Working Memory and Superior Working Memory scores are expected to increase by 4% and 5%, respectively, based on the computerized n-back test, while the Inattentiveness score could be reduced by 1%, based on the computerized attentional test (ANT).

INTERPRETATION

Urban greening as planning tool can improve behavioral and cognitive development in city children. Methods and results of our study are applicable to many cities worldwide, and similar results for children of real-life urban greening interventions can be expected.

Vulnerability assessment of heat waves within a risk framework using artificial intelligence

Current efforts to adapt to climate change are not sufficient to reduce projected impacts. Vulnerability assessments are essential to allocate resources where they are needed most. However, current assessments that use principal component analysis suffer from multiple shortcomings and are hard to translate into concrete actions. To address these issues, this article proposes a novel data-driven vulnerability assessment within a risk framework. The framework is based on the definitions from the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, but some definitions, such as sensitivity and adaptive capacity, are clarified. Heat waves that occurred between 2001 and 2018 in Quebec (Canada) are used to validate the framework. The studied impact is the daily mortality rates per cooling degree-days (CDD) region. A vulnerability map is produced to identify the distributions of summer mortality rates in aggregate dissemination areas within each CDD region. Socioeconomic and environmental variables are used to calculate impact and vulnerability. We compared abilities of AutoGluon (an AutoML framework), Gaussian process, and deep Gaussian process to model the impact and vulnerability. We offer advice on how to avoid common pitfalls with artificial intelligence and machine-learning algorithms. Gaussian process is a promising approach for supporting the proposed framework. SHAP values provide an explanation for the model results and are consistent with current knowledge of vulnerability. Recommendations are made to implement the proposed framework quantitatively or qualitatively.

The methodology of quantitative risk assessment studies

Once an external factor has been deemed likely to influence human health and a dose response function is available, an assessment of its health impact or that of policies aimed at influencing this and possibly other factors in a specific population can be obtained through a quantitative risk assessment, or health impact assessment (HIA) study. The health impact is usually expressed as a number of disease cases or disability-adjusted life-years (DALYs) attributable to or expected from the exposure or policy. We review the methodology of quantitative risk assessment studies based on human data. The main steps of such studies include definition of counterfactual scenarios related to the exposure or policy, exposure(s) assessment, quantification of risks (usually relying on literature-based dose response functions), possibly economic assessment, followed by uncertainty analyses. We discuss issues and make recommendations relative to the accuracy and geographic scale at which factors are assessed, which can strongly influence the study results. If several factors are considered simultaneously, then correlation, mutual influences and possibly synergy between them should be taken into account. Gaps or issues in the methodology of quantitative risk assessment studies include 1) proposing a formal approach to the quantitative handling of the level of evidence regarding each exposure-health pair (essential to consider emerging factors); 2) contrasting risk assessment based on human dose-response functions with that relying on toxicological data; 3) clarification of terminology of health impact assessment and human-based risk assessment studies, which are actually very similar, and 4) other technical issues related to the simultaneous consideration of several factors, in particular when they are causally linked.