Epidemiological time series studies of PM2.5 and daily mortality and hospital admissions: a systematic review and meta-analysis

Individual and joint exposure to PM2.5 constituents and incident risk of metabolic syndrome: A national cohort study

Cohort evidence linking fine particulate matter (PM2.5) constituents to metabolic syndrome (MetS) was extensively scarce. A nationwide MetS-free cohort of 3658 participants aged 45 and above, followed up from 2011 to 2015, were enrolled from 125 cities across China's mainland. Cox proportional hazards models and quantile-based g-computation were adopted to investigate individual and joint effects of exposure to PM2.5 constituents with MetS and its components. Monte Carlo simulations (n = 1000) were utilized to generate quasi-concentration-response (C-R) curve of joint exposure. A total of 633 MetS events occurred during 14,766.5 person-years follow-up (median 4.1 years). An estimated excess risk of 33 %-51 % in MetS incidence was linked to per interquartile range (IQR) increase in individual exposure to PM2.5 constituents. For an IQR-equivalent increase in joint exposure, we estimated a hazard ratio of 1.45 (95 % confidence interval: 1.23-1.69) for MetS, 1.49 (1.31-1.69) for central obesity, 1.19 (1.06-1.34) for high BP, 1.57 (1.34-1.84) for low HDL-C, 1.31 (1.14-1.51) for high TG, and 1.23 (1.02-1.48) for elevated FBG, respectively. Approximately linear or J-shaped C-R curves were consistently observed in individual and joint associations of PM2.5 constituents with MetS and its components. Joint-exposure analyses provided consistent evidence for the greatest contribution of SO42- in triggering PM2.5-associated risks of overall MetS and its components. Stratified analysis suggested higher PM2.5-related MetS risks among older participants and urban residents. These findings added longitudual population-based evidence for increased incident risks of MetS and its components associated with long-term exposures to PM2.5 constituents in middle-aged and older adults.

Investigating the acute effects of black carbon, PM2.5 exposure, and temperature on asthma and respiratory-related emergency department visits and hospitalizations in Mississippi

Globally, exposure to air pollutants (black carbon (BC) and fine particulate matter (PM2.5)) is associated with respiratory diseases, however, research is limited in the Southern United States, particularly in Mississippi. This study investigated the influence of BC, PM2.5, and temperature on daily asthma and respiratory emergency department visits and hospital admissions among individuals ≥65 years old in the Jackson, Mississippi Metropolitan Statistical Area (MSA), over a two-year period. Time-series analysis explored the exposure-lag-response relationship between environmental factors and asthma and respiratory outcomes. During the study period, a total of 1466 asthma-related and 9482 respiratory disorder-related admissions were recorded with females representing 74 % of asthma-related and 59 % of respiratory disorder-related admissions. An interquartile range (IQR: 1.42 μg m-3) increase in BC concentration was associated with an increased risk of respiratory disorder-related admissions at lag 0, with a RR of 1.013 (95 % CI: 1.001-1.026) for all data, and an RR of 1.020 (95 % CI: 1.003-1.038) for the female subgroup. Neither BC nor PM2.5 was identified to be associated with asthma-related admissions. Springtime exposure to an IQR increase in BC (1.42 μg m-3) and PM2.5 (6.91 μg m-3) significantly increased the risk of asthma-related admissions at lag 1, with a RR of 1.490 (95 % CI: 1.207-1.840) and 1.471 (95 % CI: 1.010-2.143), respectively. Lower temperatures increased the risk of respiratory disorder-related admissions, with elevated RRs observed 10-25 days post-exposure. This study indicates that BC exposure, particularly among females, was more strongly associated with respiratory disorder-related admissions than PM2.5 exposure. Temperature variations exhibited a significant impact on respiratory disorder-related admissions compared to asthma-related admissions. BC revealed a significant antagonistic interaction with temperature, while PM2.5 showed no interaction. Identifying environmental factors affecting human health in disparity-prone areas like Mississippi is crucial to protect public health.

Short-term exposure to ambient nitrogen dioxide and fine particulate matter and cause-specific mortality: A causal modeling approach in four regions

Ambient air pollution still represents a major health burden. While the link between short-term air pollution exposures and mortality has been well-documented globally, few studies have applied causal modeling approaches. Therefore, we aimed to quantify the relationship between day-to-day changes in ambient particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5) and nitrogen dioxide (NO2) levels and changes in daily natural, cardiovascular (including all-cardiovascular, cardiac, and stroke), as well as respiratory mortality rates using a causal modeling framework. Daily air pollution data and cause-specific death counts at the county, district, or municipality level from California (US), Jiangsu (China), Germany, and Lazio (Italy) were obtained for the years 2015-2019, including urban and rural populations. We used interactive fixed effects models to analyze the effects of air pollutants across different lag periods (0-2, 3-7, and 0-7 days after exposure) while accounting for both measured and unmeasured time-varying spatial unit-specific confounding factors. We observed increases in daily cardiovascular deaths (per 1 million people) per a 10 μg/m3 increase in daily NO2 at lag 0-7: 0.18 (95 % confidence interval: 0.02, 0.38) in California, 0.23 (0.14, 0.32) in Jiangsu, 0.48 (0.27, 0.70) in Germany, and -0.35 (-2.63, 1.92) in Lazio. For PM2.5, the related increases in cardiovascular mortality rates were 0.00 (-0.18, 0.18) in California, 0.04 (0.00, 0.09) in Jiangsu, 0.22 (0.06, 0.37) in Germany, and 1.96 (0.76, 3.16) in Lazio. Additionally, associations were seen for natural, cardiac, stroke, and respiratory mortality, particularly pronounced among individuals aged 75 and older. These associations were strongest with prolonged exposures and remained consistent even in two-pollutant models. This study, using a causal modeling approach and including urban and rural populations, contributes to the growing body of evidence linking increases in short-term exposure to NO2 and PM2.5 with increased cause-specific mortality rates.

Mortality risk of short-term air pollution exposure in urban and rural Chinese populations: A nationwide time-stratified case-crossover study, 2008-2020

BACKGROUND

Epidemiologic evidence underpinning current World Health Organization Air Quality Guidelines (WHO AQGs) is primarily derived from urban populations, which remains challenging for implementing the guidelines in low- and middle-income countries (LMICs) where most people reside in rural or less developed areas. Here, we aimed to characterize the associations between ambient air pollution and mortality in Chinese populations living in both urban and rural areas, where rural populations have not been studied previously at national level.

METHODS

In this nationwide time-stratified case-crossover study, we extracted non-accidental death cases of all ages in both urban and rural areas during 2008-2020 from National Mortality Surveillance System, which covered 40,300 representative township-level administration units from 29 provinces, representing nearly 24 % of Chinese population. The urban-rural classification of participants' addresses was defined based on the China's National Bureau of Statistics. Daily township-level exposures to ambient particulate matter in diameter less than 10 μm and 2.5 μm (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and 8-h maximum ozone (O3) were estimated using the Nested Air Quality Prediction Modeling System. We applied conditional logistic regression models to characterize province-specific associations of mortality risks with air pollutants, and then combined the estimates using random-effects meta-analysis.

RESULTS

A total of 61,228,962 all-cause deaths were compiled in the analysis. During the study period, 87.3 % of the death cases had PM2.5 exposure on the same day of death above current short-term guideline level of 15 μg/m3, and 35.6 % had O3 exposure above guideline level of 100 μg/m3. In this analysis, significant morality risks were observed in associations with short-term exposures to all six criteria pollutants. In specific, each 10 μg/m3 increase in PM2.5 exposure levels on the same day of death was associated with increased mortality risks of 0.22 % (95 % confidence interval [95CI %], 0.13 to 0.31). Further, when exposure levels below the guidelines of 15 μg/m3, PM2.5 exposure attributed mortality risks increased to 1.59 % (95CI %, 0.84 to 2.35), which became largely comparable with the risks observed in high-income country studies. Notably, we derived the effects attributed to nationwide O3 exposure, with association estimate of 0.18 % (95CI %, 0.11 to 0.25), which is also comparable with global estimates. The mortality risks for major criteria pollutants PM2.5, PM10, NO2, SO2, and O3 were slightly greater among urban populations than those observed in rural populations.

CONCLUSION

This nationwide study for the first time showed increased and globally comparable mortality risks of PM2.5 exposure below current guideline level, as well as significant morality risks of O3 exposure, in Chinese populations of all ages from both urban and rural areas. Our timely findings highlight the importance of global implementation of AQGs and call for immediate air quality management actions, particularly in less developed areas.

Assessing the burden of diseases attributed to exposure to ambient particulate matter by air quality modeling

This study aimed to assess PM2.5 exposure levels in Ahvaz, Iran, and quantify the associated burden of disease attributable to particulate pollution. To quantify uncertainty mortality and morbidity, the exposure response function model for probabilistic risk assessment was used. The analysis of aerosol variations by the Aerosol Optical Thickness indicated a decline in PM2.5 concentrations during pandemic. During the study period, the annual mean of PM2.5 concentrations exceeded the annual limit value established by the World Health Organization. Cause-specific mortality, including trachea bronchus lung cancer, stroke, and acute lower respiratory infections, also decreased by 14-28% in 2020. Restricted activity days and work days lost decreased by 11.8% and 13.8%, respectively, correlating with lower PM2.5 concentrations. Years lived with disability dropped from 242.7 to 170.4 years per 105 capita in 2020 during the pandemic. Mitigation strategies, including green infrastructure, industrial regulation, and improved urban planning, are needed to reduce health risks in this highly polluted region.

Personal PM2.5 Exposure and Associated Factors Among Adults with Allergic Diseases in an Urban Environment: A Panel Study

This study analyzed the factors influencing personal PM2.5 exposure levels among adults with allergic diseases in Seoul using a linear mixed-effects (LMEs) model. The average personal PM2.5 exposure concentration of the study participants was 17.38 μg/m3, exceeding the World Health Organization (WHO) daily recommended guideline (15.00 μg/m3), though it was relatively low compared to global levels. Inter-individual exposure variability was approximately 43.5%, with exposure levels varying significantly depending on microenvironments. Notably, 58% of participants exhibited higher exposure on weekends compared to weekdays, likely associated with increased outdoor activities. The LMEs model results identified smoking (90.81% higher in smokers), temperature, relative humidity, outdoor pollutants (PM2.5, O3, CO), indoor PM2.5 and CO concentrations, and time spent in residential environments as factors increasing exposure, while rainfall (91.23% reduction), wind speed, and air purifier use were identified as factors reducing exposure. These findings suggest that individual activity patterns and environmental factors significantly influence exposure levels, highlighting the need for personalized mitigation strategies and national fine dust policies. This study is expected to provide scientific evidence contributing to the reduction in health risks and improvement of quality of life for individuals with allergic diseases.

Fudosteine attenuates lung inflammation in mice with PM2.5-induced asthma exacerbation by inhibiting pyroptosis via the NLRP3/caspase-1/GSDMD pathway

This study aimed to explore the potential preventive effects of fudosteine (Fud) on PM2.5-induced asthma exacerbations in a murine model. BALB/c mice were randomly allocated into six groups: control, Fud, ovalbumin (OVA), OVA+Fud, OVA+PM2.5, and OVA+PM2.5 + Fud. An asthma model was established through OVA sensitization and challenge. Compared to the OVA group, PM2.5 exposure exacerbated allergic asthma, as evidenced by increased collagen fiber deposition, goblet cell metaplasia, mucus secretion, heightened airway inflammation, elevated total cell and eosinophil counts, and upregulated levels of interleukin (IL)-1β, IL-18, and NLRP3 expression in lung tissues. Notably, fudosteine treatment mitigated these pathological changes. Western blot analysis revealed that fudosteine significantly reduced the expression of NLRP3, caspase-1, gasdermin D (GSDMD), cleaved-caspase-1, and cleaved-GSDMD in lung tissues. In conclusion, fudosteine alleviated lung inflammation, collagen deposition, and mucus secretion in PM2.5-induced asthma exacerbation, potentially by inhibiting the NLRP3 inflammasome-mediated pyroptosis pathway.

Association between long-term ambient fine particulate matter exposure and risk of postneonatal infant mortality in Taiwan

Infants and children may be potentially susceptible to harm from ambient fine particulate matter (PM2.5) pollution because of the following characteristics (1) immature immune systems (2) not yet fully developed respiratory systems (3) possess a higher absorption rate of pollutants, and (4) and daily activities may expose infants to varying levels. However, few studies have examined the possible correlation between exposure to PM2.5 and mortality in infants. Therefore, the aim of this study was to investigate the association between long-term exposure to ambient PM2.5 and post-neonatal mortality in 65 municipal areas across Taiwan. The mean annual PM2.5 levels of each municipality were categorized from 2013 to 2022 and divided into tertiles. The natural logarithm of the annual post-neonatal mortality rates per 1000 live births was assessed with respect to PM2.5 level, urbanization level, physician density, and mean annual average household income. Weighted-multiple linear regression was utilized to compute the adjusted RRs and their 95% confidence intervals (CIs). When data were not stratified by PM2.5 levels, a significant positive association was observed between long-term lifetime exposure to ambient PM2.5 and post-neonatal mortality rates after adjustment for physician density, urbanization level, and average household income. When PM2.5 levels (in tertiles) were stratified, a positive but nonsignificant trend was found in post-neonatal mortality frequency from the lowest to the highest PM2.5 category. These findings suggest that long-term exposure to PM2.5 increases the risk of post-neonatal mortality rates in Taiwan.

Regional Differences in PM2.5 Chemical Composition and Inhalation Risk Assessment: A Case Study of Seoul, Incheon, and Wonju

This study evaluates the chemical components of an aerodynamic diameter less than 2.5 μm (PM2.5) and its health risks in Seoul, Incheon, and Wonju, South Korea. The results revealed significant regional variations, particularly under the reasonable maximum exposure scenario, with Seoul's average daily dose (6.4 × 10-1 µg/kg/day) approximately 2 times higher than Incheon (5.8 × 10-1 µg/kg/day) and Wonju (3.2 × 10-1 µg/kg/day) under the central tendency exposure scenario. Furthermore, exposure to the chemical components comprising PM2.5 can surpass risk thresholds when PM2.5 concentrations exceed the national standard levels. These findings suggest the potential benefits of preventive measures, such as minimizing outdoor exposure, especially for individuals over 60 years of age, to help reduce health risks. However, further research is needed to confirm the effectiveness of these measures in different regions. The study also highlighted the variation in the health impacts of PM2.5 concentrations and its chemical components across the different regions. The results suggest that relying solely on PM2.5 concentrations for health risk assessments may underestimate the risks associated with carcinogenic components such as chromium (Cr, VI). However, under the reasonable maximum exposure (RME) scenario, the excess cancer risk (ECR) for Cr (VI) exceeds the acceptable threshold in all three regions, suggesting a high carcinogenic risk under the RME scenario. For example, the ECR for Cr(VI) in Seoul was calculated as 1.4 × 10-4, Incheon as 2.0 × 10-4, and Wonju as 1.2 × 10-4. Therefore, we emphasize the importance of incorporating both the mass concentration of PM2.5 and its chemical constituents when conducting health risk assessments to inform region-specific health policies to mitigate health risks, particularly for vulnerable populations.

The causal links between long-term exposure to major chemical components of PM2.5 and overall outpatient visits in mainland China: A nationwide study in the difference-in-differences framework

INTRODUCTION

Although the adverse health effects of PM2.5 exposure has been well documented, evidence of its adverse effect on overall outpatient visits was still limited. Besides, the adverse health effects of PM2.5 exposure get complicated due to various components within the particles. So far, little is known about the relationship between PM2.5 components and overall outpatient visits.

OBJECTIVES

This study aims to evaluate the causal relationships between long-term exposure to primary chemical components of PM2.5 and outpatient visits, while estimating the mixture effect and relative contribution of the components.

METHODS

Based on nationwide provincial-level surveillance data of outpatient visits in China and well-validated simulations of PM2.5 components concentration, we employed the Difference-In-Differences (DID) approach to evaluate the causal relationships between long-term exposure to primary chemical components of PM2.5 and outpatient visits, and used a Bayesian Weighted Quantile Sum (BWQS) regression to assess the mixture effect of the components.

RESULTS

We found a 20.44% increase in the risk (IR%) of outpatient visits following each InterQuartile Range (IQR) increment in PM2.5 concentration. Our estimation further suggested a 17.07%, 15.91%, and 14.04% increase in the risk of outpatient visits for organic matter, sulfate, and nitrate, but non-significant increases for other components. However, when considering the inter-components correlation, sulfate and black carbon contributed most (42.3% and 28.1%, respectively) to the overall mixture effect of PM2.5 which was indicated by a 4.84% increase (95%CI: 1.92%, 7.83%) in the risk of outpatient visits following every unit increase in the overall BWQS index. Additionally, stratified analyses showed a stronger association among aged provinces and provinces with lower education rates.

CONCLUSION

Our findings would improve understanding of the individual and mixture impact of major chemical components of PM2.5 and may contribute to more targeted and optimized environmental programs for pollution control.

Applying Finite Mixture Models to Quantify Respirable Dust Mass in Coal and Metal-Nonmetal Mines Using Fourier Transform Infrared Spectroscopy

Respirable dust mass is a prevalent occupational health hazard to the mining workforce. Mineral matrices observed in the mine environment are complex, time varying, and heterogeneous. This poses a challenge to assessing dust exposure using Fourier transform infrared (FT-IR) spectrometry as calibrations for constituent dust species (e.g., crystalline silica) have historically been trained using homogeneous standards or simple mixtures therein. Investigations have considered direct-on-filter analysis, which collects FT-IR spectra directly from sampling filters for calibration, as an alternative. Direct-on-filter analysis using a partial least squares (PLS) method has gained particular interest recently due to the potential to rapidly quantify multiple species from a single filter at the mine site. By design, heterogeneity, and its presumed impact on method accuracy, cannot be addressed in the laboratory when using a direct-on-filter approach motivating the need for more advanced calibration approaches. When heterogeneity is present, mixture of experts (MoE) finite mixture models offer a promising and novel alternative to PLS direct-on-filter analysis as MoE incorporates cluster discovery, regression, and outlier identification into model fitting. Three MoE models of increasing complexity were tasked with determining respirable dust mass in 243 field samples from thirteen active coal, limestone, sandstone, and silver mines. All MoE models, including those using only "expert" spectroscopic predictors or a combination of expert and categorical "gate" variables (e.g., mine type), significantly outperform PLS in terms of accuracy (α = 0.05). Decomposing bias by mine type shows that accuracy generally improves across all types considered when MoE models are not overfitted. The MoE method's effectiveness was linked to its ability to endogenously classify outliers as well as possibly to the use of an additional cluster model for mass predictions. Overall, MoE methods appear as a capable and novel tool to addressing problems of heterogeneity for direct-on-filter quantitative analysis.

Airborne particulate matter inhalation bioaccessibility: A review of methodological aspects

Research has consistently linked exposure to particulate matter (PM) with adverse health outcomes, including cardiovascular and pulmonary morbidity and mortality. Understanding the mechanisms by which PM leads to these effects on human health is crucial for developing effective mitigation strategies. One aspect of PM research that has gained increasing attention in the past few years is the bioaccessibility of inhaled PM-bound pollutants that have potential to cause adverse health effects. To assess the bioaccessibility of PM-bound pollutants, such as polycyclic aromatic hydrocarbons, phthalate esters, organophosphorus flame retardants and metal(loid)s, simulated lung fluids (SLF) are used as a tool to mimic the conditions in the human respiratory system. In addition to different SLF, various extraction methodologies and experimental conditions (e.g., incubation period, solid to liquid ratio, and pH) have been employed to extract the bioaccessible part of these pollutants, though there is not yet a standardised procedure to do so. This review aims to critically evaluate existing inhalation bioaccessibility methodologies and explore their connection with PM characteristics. More research is needed, and a standardised procedure should be implemented to allow the comparation of data between studies. Better in vitro-in vivo relationships need to be established to enhance the feasibility of in vitro bioaccessibility assays as surrogates in human health exposure assessments. Long-term effects of bioaccessible pollutants and any potential synergetic effects between multiple contaminants should also be explored to assess health repercussions more thoroughly.

A comparative analysis of three PM2.5 exposure metrics and their impact on respiratory disease hospitalizations in Lanzhou, China

Research on the associations between PM2.5 and total respiratory diseases (RD) in Lanzhou is limited. We investigated the short-term impact of PM2.5 on total RD hospitalizations in Lanzhou (2015-2019) using various exposure metrics. We collected data on hospitalizations, daily air pollutant concentrations, and meteorological factors during the study period. Daily excessive concentration hours (DECH) were calculated according to the World Health Organization's air quality guidelines. A distributional lag nonlinear model (DLNM) based on a generalized additive model (GAM) was used to comparatively analyze the association between three PM2.5 exposure metrics (DECH (DECH PM2.5), daily mean concentration (Mean PM2.5), and hourly peak concentration (Peak PM2.5)) and RD hospitalizations. Subgroup analyses and sensitivity analyses were also performed. We found similar effects on RD hospitalizations using DECH PM2.5 and Mean PM2.5, but relatively weak associations observed using Peak PM2.5. The cumulative lag effect increased daily. Subgroup analyses showed that females and children aged 0-17 years were more susceptible to PM2.5 pollution and that the association was enhanced during the cold season. Our research strengthened the evidence that exposure to ambient PM2.5 increases the risk of RD. This study revalidated the reliability of the new metrics and confirmed that DECH PM2.5 effect estimates for exposure-disease were more accurate than the Mean PM2.5.

Wildfire Air Pollution and Rates of Cardiovascular Events and Mortality in Northern California in 2018

BACKGROUND

We examined the association between acute cardiovascular disease (CVD) events and wildfire air pollution in California in 2018.

METHODS

The study included adult (≥18 years) members of Kaiser Permanente Northern California, an integrated health care system. Outcomes included CVD events (hospitalizations for acute myocardial infarction, heart failure, or stroke, and CVD death) and death from any cause. Fine particulate air pollution (particulate matter <2.5 microns in diameter; PM2.5) exposure was assessed in categories (Good <12 μg/m3, Moderate 12-34 μg/m3, High ≥35 μg/m3) and continuously. Poisson time series regression was used to model daily event rates during July 1 to December 31, 2018, using a spline to adjust for long-term time trends. We calculated rate ratios (RR) to estimate the association between wildfire air pollution and daily rate of CVD events and deaths.

RESULTS

Our study included 3.2 million adults with a total follow-up of 587.9 million person-days. High PM2.5 concentrations during the Mendocino Complex wildfire in July to August was associated with an increased rate of CVD events (RR, 1.231 [95% CI, 1.039-1.458]) and death (RR, 1.358 [95% CI, 1.128-1.635]) compared with Good PM2.5 concentrations. In contrast, there was no evidence of increased risk during the Camp wildfire in November (RR for CVD events, 0.966 [95% CI, 0.894-1.044]; RR for all-cause mortality, 0.985 [95% CI, 0.904-1.074] High versus Good PM2.5 concentrations).

CONCLUSIONS

There was some evidence of increased rates of CVD events and death during wildfires, but results were inconsistent. With ongoing climate change, large wildfires are a pressing public health concern and future work is needed to understand differences in health outcomes by wildfire.

Online Measurements during Simulated Atmospheric Aging Track the Strongly Increasing Oxidative Potential of Complex Combustion Aerosols Relative to Their Primary Emissions

Oxidative potential (OP) is increasingly recognized as a more health-relevant metric than particulate matter (PM) mass concentration because of its response to varying chemical compositions. Given the limited research on the OP of complex combustion aerosols, the effects of aging processes on their OP remain underexplored. We used online instruments to track the evolution of OP [via dithiothreitol (DTT) assays] during the aging of wood burning and coal combustion emissions by hydroxyl-radical-driven photooxidation and dark ozonolysis. We observed very substantial increases in the intrinsic OP (OPm DTT) of complex combustion aerosols (e.g., OPm DTT up to 100 pmol min-1 μg-1 for OH-aged wood burning emissions) within 1 day of equivalent aging. Further analysis in relation to the degree of oxidation revealed a potential for generalizing the OP of carbonaceous aerosols with average carbon oxidation state values ranging from -1.5 to -0.5 by assuming they have a constant OPm DTT value of ∼10 ± 6 pmol min-1 μg-1. Additionally, we uncovered a strong dependency of OPm DTT on both the source/precursor and aging pathway with above ∼-0.5. OH photooxidation was identified as an exceptionally efficient pathway for generating highly oxidized, multifunctionalized, and DTT-active products, particularly from wood burning emissions.

Respiratory Protective Effects of Perilla Leave Varieties (Perilla frutescens) Against Fine Particulate Matter (PM2.5)-induced Damage in Human Nasal Cells

Fine particulate matter (PM2.5) is known to exacerbate chronic respiratory disorders, primarily by inducing inflammatory responses and mucus overproduction. Perilla leaves are reported to have significant health benefits, such as antioxidant, antibacterial, and antiallergic properties, attributed to phenolic compounds that vary depending on genetic diversity. In this study, flavonoid-rich extracts (FRE) from 56 perilla leaf varieties and genetic resources were prepared and screened using a mass screening system. The screening focused on evaluating their anti-inflammatory, mucus-reducing, and respiratory protective effects against PM2.5-induced damage in human nasal cells (RPMI2650). Parameters such as cell viability, nitric oxide (NO) levels, and mucus secretion factor (MUC5AC) concentrations were assessed. Among the 56 varieties, Perilla frutescens var. crispa (YCPL706), sourced from Ulleung Island, Korea, exhibited the highest cell viability (112.50%, 100 μg/mL), lowest NO concentration (9.98 μM, 100 μg/mL), and MUC5AC level (78.65 ng/mL, 100 μg/mL). Further evaluation of YCPL706 FRE demonstrated significant respiratory protective effects, including the inhibition of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), MUC5AC, and oxidative stress factors (MDA and ROS), compared to the control cultivar Namcheon. YCPL706 also showed strong antibacterial activity against Pseudomonas aeruginosa (minimum inhibitory concentration: 5 mg/mL). These findings suggest that the genetic resource YCPL706 is a promising candidate for combating PM2.5-induced respiratory damage due to its potent anti-inflammatory, antioxidant, and antibacterial properties.

Performance of fine particulate matter data on air quality in an epidemiological study in Salvador, Brazil

OBJECTIVE

To evaluate the performance of satellite-derived PM2.5 concentrations against ground-based measurements in the municipality of Salvador (state of Bahia, Brazil) and the implications of these estimations for the associations of PM2.5 with daily non-accidental mortality.

METHODS

This is a daily time series study covering the period from 2011 to 2016. A correction factor to improve the alignment between the two data sources was proposed. Effects of PM2.5 were estimated in Poisson generalized additive models, combined with a distributed lag approach.

RESULTS

According to the results, satellite data underestimated the PM2.5 levels compared to ground measurements. However, the application of a correction factor improved the alignment between satellite and ground-based data. We found no significant differences between the estimated relative risks based on the corrected satellite data and those based on ground measurements.

CONCLUSION

In this study we highlight the importance of validating satellite-modeled PM2.5 data to assess and understand health impacts. The development of models using remote sensing to estimate PM2.5 allows the quantification of health risks arising from the exposure.

Modifying factors and temporal trends of adverse health effects of short-term exposure to PM2.5 in Canada (2001-2018)

Considerable evidence has been accumulated on serious acute health outcomes associated with short-term exposure to ambient fine particulate matter (PM2.5). Modifying factors of those associations, however, have been less explored and need further analyses. In this national study, we investigated whether short-term effects of PM2.5 are modified according to region, cause of mortality/hospitalization, season, age, and sex. PM2.5-related adverse health effects were estimated by an ecological time-series study, covering about 80 % of the Canadian population for 18 years (2001-2018). We estimated city-specific associations using daily averages of PM2.5 and temperature, and daily counts of hospitalizations and mortality (non-accidental all-cause, circulatory, and respiratory). National and regional associations were then estimated with a 2-stage model. We considered potential modifying factors of PM2.5-related adverse health effects, and examined linear trends in the annual associations. Nationally, PM2.5 exposure was associated with both hospitalizations and mortality, and there was evidence of differences by the modifying factors. Of the various causes, circulatory mortality and respiratory hospitalization were more attributable to PM2.5 exposure. We found regional differences for both all-cause hospitalization and all-cause mortality, and seasonal differences for respiratory hospitalization (warm season) and circulatory hospitalization (cold season). Circulatory mortality risk was significant for seniors and females. All-cause hospitalizations appeared to gradually decrease over time, but annual all-cause mortality remained constant at 0.6 % of the population. Adverse health effects of PM2.5 exposures may depend on not only PM2.5 concentration, but also other factors (region, cause, season, age, sex). National estimates for the baseline (age ≥ 1 year, both sexes) risk cannot be interpreted without consideration of the differences by modifying factors. Study findings can be used by seniors, women, and those who have pre-existing health conditions to make informed decisions regarding their health risks from daily exposure to ambient PM2.5.

Visualization and analysis of PM2.5 health effects, 2013 to 2023: Bibliometrics of PM2.5 and health effects

BACKGROUND

To analyze the current status, hotspots, and cutting-edge trends of PM2.5 health effects of PM2.5, using CiteSpace.

METHODS

The Web of Science Core Collection Science Citation Index Expanded was searched for relevant articles from January 1, 2013, to December 31, 2023. Network maps identifying authors, institutions, countries, keywords, co-cited authors, journals, references, and research trends were then created using CiteSpace.

RESULTS

A total of 2174 articles on the health effects of PM2.5 were identified between 2013 and 2023, with an increasing trend in annual publications. The United States had the highest number of articles on this topic, followed by China. The Chinese Academy of Sciences (CAS) is the leading institute in terms of paper production. Hoek was the most prolific author, focusing on the health consequences of air pollution. Among referenced journals, ENVIRON HEALTH PERSP ranked first, while Pope Ca was the most cited author. Current research focuses on reactive oxygen species (ROS), inflammation, oxidative stress, cardiovascular and respiratory diseases, PM2.5 sources, and chemical composition. The field is currently experiencing a phase of rapid expansion.

CONCLUSION

The findings of this bibliometric analysis offer insight into the status and direction of research on PM2.5 and its health impacts, which aid scientists in coming up with new directions for their investigation.

Ventilation heterogeneity is increased in adults exposed to coal mine fire-related PM2.5

BACKGROUND AND OBJECTIVES

The Hazelwood Health Study was set up to study long-term health effects of a mine fire that blanketed residents of the Latrobe Valley with smoke for 45 days in 2014. The Respiratory Stream specifically assessed the impact of fine particulate matter <2.5 μm diameter (PM2.5) exposure from mine fire smoke on lung health. The multiple breath nitrogen washout (MBW) test assesses ventilation heterogeneity, which may detect sub-clinical airways dysfunction not identified using standard tests such as spirometry. This analysis assessed the association of PM2.5 exposure with measures of ventilation heterogeneity.

METHODS

Exposed (Morwell) and unexposed (Sale) participants were recruited 3.5-4 years after the fire from those who had participated in an Adult Survey. MBW was performed to measure lung clearance index (LCI), functional residual capacity (FRC), acinar (Sacin) and conductive (Scond) ventilation heterogeneity. PM2.5 exposure was estimated with emission and chemical transport models. Multivariable linear regression models were fitted controlling for confounders.

RESULTS

We recruited 519 participants. MBW tests were conducted on 504 participants with 479 acceptable test results (40% male; 313 exposed, 166 unexposed). Exposure to mine fire-related PM2.5 was associated with increasing Scond (β = 1.57/kL, 95%CI: 0.20-2.95, p = 0.025), which was comparable to the estimated effect on Scond of 4.7 years of aging. No other MBW outcomes were statistically different.

CONCLUSION

Increasing exposure to PM2.5 was associated with increased ventilation heterogeneity in the conductive region of the lungs 4 years after the event.

Key factors in epidemiological exposure and insights for environmental management: Evidence from meta-analysis

In recent years, the precision of exposure assessment methods has been rapidly improved and more widely adopted in epidemiological studies. However, such methodological advancement has introduced additional heterogeneity among studies. The precision of exposure assessment has become a potential confounding factors in meta-analyses, whose impacts on effect calculation remain unclear. To explore, we conducted a meta-analysis to integrate the long- and short-term exposure effects of PM2.5, NO2, and O3 on all-cause, cardiovascular, and respiratory mortality in the Chinese population. Literature was identified through Web of Science, PubMed, Scopus, and China National Knowledge Infrastructure before August 28, 2023. Sub-group analyses were performed to quantify the impact of exposure assessment precisions and pollution levels on the estimated risk. Studies achieving merely city-level resolution and population exposure are classified as using traditional assessment methods, while those achieving sub-kilometer simulations and individual exposure are considered finer assessment methods. Using finer assessment methods, the RR (under 10 μg/m3 increment, with 95% confidence intervals) for long-term NO2 exposure to all-cause mortality was 1.13 (1.05-1.23), significantly higher (p-value = 0.01) than the traditional assessment result of 1.02 (1.00-1.03). Similar trends were observed for long-term PM2.5 and short-term NO2 exposure. A decrease in short-term PM2.5 levels led to an increase in the RR for all-cause and cardiovascular mortality, from 1.0035 (1.0016-1.0053) and 1.0051 (1.0021-1.0081) to 1.0055 (1.0035-1.0075) and 1.0086 (1.0061-1.0111), with weak between-group significance (p-value = 0.13 and 0.09), respectively. Based on the quantitative analysis and literature information, we summarized four key factors influencing exposure assessment precision under a conceptualized framework: pollution simulation resolution, subject granularity, micro-environment classification, and pollution levels. Our meta-analysis highlighted the urgency to improve pollution simulation resolution, and we provide insights for researchers, policy-makers and the public. By integrating the most up-to-date epidemiological research, our study has the potential to provide systematic evidence and motivation for environmental management.

Environmental Risk Factors for Acute Respiratory Distress Syndrome

Several environmental exposures increase susceptibility to the acute respiratory distress syndrome (ARDS). Specifically, chronic exposure to ambient air pollution, cigarette smoke, and alcohol "prime" the lung via epithelial injury, endothelial dysfunction, and immunomodulatory mechanisms, increasing the risk and severity of ARDS following an array of acute insults. Future research of these pathways may reveal therapeutic targets. Relevant emerging threats, such as electronic cigarettes and vaping, wildfire smoke, and the environmental hazards associated with climate change, may also be associated with ARDS. Building upon existing public policy interventions can prevent substantial morbidity and mortality from ARDS.

Oxidative Stress Induced by Air Pollution

In 2021, the World Health Organization issued new guidelines on particulate matter (PM), including PM2 [...].

Preoperative Exposure to Fine Particulate Matter and Risk of Postoperative Complications: A Single Center Observational Cohort Bayesian Analysis

Background

While exposure to fine particulate matter air pollution (PM 2.5 ) is known to cause adverse health effects, its impact on postoperative outcomes in US adults remains understudied. Perioperative exposure to PM 2.5 may induce inflammation that interacts insidiously with the surgical stress response, leading to higher postoperative complications.

Methods

We conducted a single center, retrospective cohort study using data from 49,615 surgical patients living along Utah's Wasatch Front and who underwent elective surgical procedures at a single academic medical center from 2016-2018. Patients' addresses were geocoded and linked to daily Census-tract level PM 2.5 estimates. We hypothesized that elevated PM 2.5 concentrations in the week prior to surgery would be associated with an increase in a bundle of major postoperative complications. A hierarchical Bayesians regression model was fit adjusting for age, sex, season, neighborhood disadvantage, and the Elixhauser index of comorbidities.

Results

Postoperative complications increased in a dose-dependent manner with higher concentrations of PM 2.5 exposure, with a relative increase of 8% in the odds of complications (OR=1.082) for every 10ug/m 3 increase in the highest single-day 24-hr PM 2.5 exposure during the 7 days prior to surgery. For a 30 fold increase in PM 2.5 (1 ug/m 3 to 30ug/m 3 ) the odds of complication rose to over 27% (95%CI: 4%-55%). The association persisted after controlling for comorbidities and confounders; our inferences were robust to modeling choices and sensitivity analysis.

Conclusions

In this large Utah cohort, exposure to elevated PM 2.5 concentrations in the week before surgery was associated with a dose-dependent increase in postoperative complications, suggesting a potential impact of air pollution on surgical outcomes. These findings merit replication in larger datasets to identify populations at risk and define the interaction and impact of different pollutants. PM 2.5 exposure is a potential perioperative risk factor and, given the unmitigated air pollution in urban areas, a global health concern.

Spatial associations of daily PM2.5 concentration with cardiovascular and pulmonary morbidity in Korea

Air pollution, particularly fine particulate matter less than 2.5 μm in diameter (PM2.5), contributes to respiratory and cardiovascular diseases and poses significant public health risks worldwide. This study evaluated the short-term effects of PM2.5 on hospital admissions for cardiovascular and respiratory diseases, with additional analyses to identify vulnerable populations based on regional characteristics. The present study analyzed data from 249 Korean communities between 2006 and 2021. Data on daily hospital admissions for cardiovascular and respiratory diseases were obtained from the National Health Insurance Service. Data on PM2.5 concentrations were sourced from air quality modeling. Additional data on regional characteristics, including the regional deprivation index, proportion of elderly residents, education levels, and greenness levels, were also collected. We used case time series analysis to assess the associations between PM2.5 concentrations and hospital admissions for cardiovascular and respiratory diseases and explored effect modification by regional characteristics with stratified analyses. The mean numbers of daily cardiovascular admissions and respiratory admissions were 5.68 ± 5.46 and 6.46 ± 8.03, respectively. The mean PM2.5 concentrations were 23.58 ± 13.66 μg/m3. A10 μg/m³ increment in daily PM2.5 concentration was associated with increase of cardiovascular and respiratory hospitalization by 0.94% (95% CI: 0.84%, 1.04%) and 1.43% (95% CI: 1.34%, 1.52%), respectively. Regional characteristics analysis showed significant disparities, with higher risks for hospital admissions in areas with lower deprivation and low greenness. This study highlights the significant short-term health impacts of PM2.5 on respiratory and cardiovascular hospital admissions in Korean communities. The findings underscore the critical role of regional and demographic factors in modulating these effects, identifying socio-economic areas, age structure of the population, lower education levels, and low greenness as key vulnerability factors.

PM2.5 and its components and respiratory disease healthcare encounters - Unanticipated increased exposure-response relationships in recent years after environmental policies

Prior studies reported excess rates (ERs) of cardiorespiratory events associated with short-term increases in PM2.5 concentrations, despite implementation of pollution-control policies. In 2017, Federal Tier 3 light-duty vehicle regulations began, and to-date there have been no assessments of population health effects of the policy. Using the NYS Statewide Planning and Research Cooperative System (SPARCS) database, we obtained hospitalizations and ED visits with a principal diagnosis of asthma or chronic obstructive pulmonary disease (COPD) for residents living within 15 miles of six urban PM2.5 monitoring sites in NYS (2014-2019). We used a time-stratified case-crossover design and conditional logistic regression (adjusting for ambient temperature, relative humidity, and weekday) to estimate associations between PM2.5, POC (primary organic carbon), SOC (secondary organic carbon), and rates of respiratory disease hospitalizations and emergency department (ED) visits from 2014 to 2019. We evaluated demographic disparities in these relative rates and compared changes in ERs before (2014-2016) and after Tier 3 implementation (2017-2019). Each interquartile range increase in PM2.5 was associated with increased ERs of asthma or COPD hospitalizations and ED visits in the previous 7 days (ERs ranged from 1.1%-3.1%). Interquartile range increases in POC were associated with increased rates of asthma ED visits (lag days 0-6: ER = 2.1%, 95% CI = 0.7%, 3.6%). Unexpectedly, the ERs of asthma admission and ED visits associated with PM2.5, POC, and SOC were higher during 2017-2019 (after Tier 3) than 2014-2016 (before Tier-3). Chronic obstructive pulmonary disease analyses showed similar patterns. Excess Rates were higher in children (<18 years; asthma) and seniors (≥65 years; COPD), and Black, Hispanic, and NYC residents. In summary, unanticipated increases in asthma and COPD ERs after Tier-3 implementation were observed, and demographic disparities in asthma/COPD and PM2.5, POC, and SOC associations were also observed. Future work should confirm findings and investigate triggering of respiratory events by source-specific PM.

Associations between short-term exposure to airborne carbonaceous particles and mortality: A time-series study in London during 2010-2019

Exposure to ambient particulate matter (PM) has been identified as a major global health concern; however, the importance of specific chemical PM components remains uncertain. Recent studies have suggested that carbonaceous aerosols are important detrimental components of the particle mixture. Using time-series methods, we investigated associations between short-term exposure to carbonaceous particles and mortality in London, UK. Daily counts of non-accidental, respiratory, and cardiovascular deaths were obtained between 2010 and 2019. For the same period, daily concentrations of carbonaceous particles: organic (OC), elemental (EC), wood-burning (WC), total carbon (TC) and equivalent black carbon (eBC) were sourced from two centrally located monitoring sites (one urban-traffic and one urban-background). Generalized additive models were used to estimate the percentage change in mortality risk associated with interquartile range increases in particulate concentrations. Lagged effects up to 3 days were examined. Stratified analyses were conducted by age, sex, and season, separate analyses were also performed by site-type. For non-accidental mortality, positive associations were observed for all particle species at lag1, including statistically significant percentage risk changes in WC (0.51% (95%CI: 0.19%, 0.82%) per IQR (0.68 μg/m3)) and OC (0.45% (95%CI: 0.04%, 0.87% per IQR (2.36 μg/m3)). For respiratory deaths, associations were greatest for particulate concentrations averaged over the current and previous 3 days, with increases in risk of 1.70% (95%CI: 0.64%, 2.77%) for WC and 1.31% (95%CI: -0.08%, 2.71%) for OC. No associations were found with cardiovascular mortality. Results were robust to adjustment for particle mass concentrations. Stratified analyses suggested particulate effects were greatest in the summer and respiratory associations more pronounced in females. Our findings are supportive of an association between carbonaceous particles and non-accidental and respiratory mortality. The strongest evidence of an effect was for WC; this is of significance given the rising popularity of wood-burning for residential space heating and energy production across Europe.

Ambient Air Pollution Exposure and Outcomes in Patients Receiving Lung Transplant

Importance

Elevated ambient fine particulate matter (PM2.5) air pollution exposure has been associated with poor health outcomes across several domains, but its associated outcomes among lung transplant recipients are poorly understood.

Objective

To investigate whether greater PM2.5 exposure at the zip code of residence is associated with a higher hazard for mortality and graft failure in patients with lung transplants.

Design, Setting, and Participants

This retrospective cohort study used panel data provided by the United Network for Organ Sharing, which includes patients receiving transplants across all active US lung transplant programs. Adult patients who received lung transplants between May 2005 and December 2016 were included, with a last follow-up of September 10, 2020. Data were analyzed from September 2022 to May 2023.

Exposure

Zip code-level annual PM2.5 exposure was constructed using previously published North American estimates.

Main Outcomes and Measures

The primary outcome was time to death or lung allograft failure after lung transplant. A gamma shared frailty Cox proportional hazards model was used to produce unadjusted and adjusted hazard ratios (HRs) to estimate the association of zip code PM2.5 exposure at the time of transplant with graft failure or mortality.

Results

Among 18 265 lung transplant recipients (mean [SD] age, 55.3 [13.2] years; 7328 female [40.2%]), the resident zip code's annual PM2.5 exposure level was greater than or equal to the Environmental Protection Agency (EPA) standard of 12μg/m3 for 1790 patients (9.8%) and less than the standard for 16 475 patients (90.2%). In unadjusted analysis, median graft survival was 4.87 years (95% CI, 4.57-5.23 years) for recipients living in high PM2.5 areas and 5.84 years (95% CI, 5.71-5.96 years) for recipients in the low PM2.5 group. Having an annual PM2.5 exposure level greater than or equal to the EPA standard 12 μg/m3 was associated with an increase in the hazard of death or graft failure (HR, 1.11; 95% CI, 1.05-1.18; P < .001) in the unadjusted analysis and after adjusting for covariates (HR, 1.08; 95% CI, 1.01-1.15; P = .02). Each 1 μg/m3 increase in exposure was associated with an increase in the hazard of death or graft failure (adjusted HR, 1.01; 95% CI, 1.00-1.02; P = .004) when treating PM2.5 exposure as a continuous variable.

Conclusions and Relevance

In this study, elevated zip code-level ambient PM2.5 exposure was associated with an increased hazard of death or graft failure in lung transplant recipients. Further study is needed to better understand this association, which may help guide risk modification strategies at individual and population levels.

Impact of the environmental pollution on cardiovascular diseases: From epidemiological to molecular evidence

Environmental pollution poses a significant threat to human health, particularly concerning its impact on cardiovascular diseases (CVDs). This review synthesizes epidemiological and molecular evidence to elucidate the intricate relationship between environmental pollutants and CVDs. Epidemiological studies highlight the association between exposure to air, water, and soil pollutants and increased CVD risk, including hypertension, coronary artery disease, and stroke. Furthermore, molecular investigations unravel the underlying mechanisms linking pollutant exposure to CVD pathogenesis, such as oxidative stress, inflammation, endothelial dysfunction, and autonomic imbalance. Understanding these molecular pathways is crucial for developing targeted interventions and policy strategies to mitigate the adverse effects of environmental pollution on cardiovascular health. By integrating epidemiological and molecular evidence, this review provides insights into the complex interplay between environmental factors and CVDs, emphasizing the urgent need for comprehensive preventive measures and environmental policies to safeguard public health.

Effect of PM2.5 on burden of mortality from non-communicable diseases in northern Thailand

Background

Particulate pollution, especially PM2.5from biomass burning, affects public and human health in northern Thailand during the dry season. Therefore, PM2.5exposure increases non-communicable disease incidence and mortality. This study examined the relationship between PM2.5and NCD mortality, including heart disease, hypertension, chronic lung disease, stroke, and diabetes, in northern Thailand during 2017-2021.

Methods

The analysis utilized accurate PM2.5data from the MERRA2 reanalysis, along with ground-based PM2.5measurements from the Pollution Control Department and mortality data from the Division of Non-Communicable Disease, Thailand. The cross-correlation and spearman coefficient were utilized for the time-lag, and direction of the relationship between PM2.5and mortality from NCDs, respectively. The Hazard Quotient (HQ) was used to quantify the health risk of PM2.5to people in northern Thailand.

Results

High PM2.5 risk was observed in March, with peak PM2.5concentration reaching 100 µg/m3, with maximum HQ values of 1.78 ± 0.13 to 4.25 ± 0.35 and 1.45 ± 0.11 to 3.46 ± 0.29 for males and females, respectively. Hypertension significantly correlated with PM2.5levels, followed by chronic lung disease and diabetes. The cross-correlation analysis showed a strong relationship between hypertansion mortality and PM2.5at a two-year time lag in Chiang Mai (0.73) (CI [-0.43-0.98], p-value of 0.0270) and a modest relationship with chronic lung disease at Lampang (0.33) (a four-year time lag). The results from spearman correlation analysis showed that PM2.5concentrations were associated with diabetes mortality in Chiang Mai, with a coefficient of 0.9 (CI [0.09-0.99], p-value of 0.03704). Lampang and Phayao had significant associations between PM2.5 and heart disease, with coefficients of 0.97 (CI [0.66-0.99], p-value of 0.0048) and 0.90 (CI [0.09-0.99], p-value of 0.0374), respectively, whereas Phrae had a high coefficient of 0.99 on stroke.

Effectiveness of respiratory face masks in reducing acute PM2.5 pollution exposure during peak pollution period in Delhi

The cities of North India, such as Delhi, face a significant public health threat from severe air pollution. Between October 2021 and January 2022, 79 % of Delhi's daily average PM2.5 (Particulate matter with an aerodynamic diameter ≤ 2.5 μm) values exceeded 100 μg/m3 (the permissible level being 60 μg/m3 as per Indian standards). In response to this acute exposure, using Respiratory Face Masks (RFMs) is a cost-effective solution to reduce immediate health risks while policymakers develop long-term emission control plans. Our research focuses on the health and economic benefits of using RFMs to prevent acute exposure to PM2.5 pollution in Delhi for different age groups. Our findings indicate that, among the fifty chosen RFMs, M50 has greatest potential to prevent short-term excess mortality (908 in age ranges 5-44), followed by M49 (745) and M48 (568). These RFMs resulted in estimated economic benefits of 500.6 (46 %), 411.1 (37 %), and 313.4 (29 %) million Indian Rupee (INR), respectively during October-January 2021-22. By wearing RFMs such as M50, M49, and M48 during episodes of bad air quality, it is estimated that 13 % of short-term excess mortality and associated costs could be saved if at least 30 % of Delhi residents followed an alert issued by an operational Air Quality Early Warning System (AQEWS) developed by the Ministry of Earth Sciences. Our research suggests that RFMs can notably decrease health and economic burdens amid peak PM2.5 pollution in post-monsoon and winter seasons until long-term emission reduction strategies are adopted. It is suggested that an advisory may be crafted in collaboration with statutory bodies and should be disseminated to assist the vulnerable population in using RFMs during winter. The analysis presented in this research is purely science based and outcomes of study are in no way to be construed as endorsement of product.

Estimated mortality attributable to the urban heat island during the record-breaking 2022 heatwave in London

The United Kingdom experienced its most extreme heatwave to date during late July 2022, with maximum air temperatures exceeding 40 °C recorded for the first time in history on July 19th. High ambient temperatures have been statistically shown to lead to increased mortality. Higher nighttime temperatures that occur in more urbanised areas, called the urban heat island (UHI), may contribute to the mortality burden of heat. In this study, we applied health impact assessment methods with advanced urban climate modelling to estimate what contribution the UHI had on the mortality impact of the 10-25 July 2022 heatwave in Greater London. Estimated mortality due to heat and due to the UHI were compared with estimated mortality due to air pollution in the same period, based on monitored concentrations. We estimate that of the 1773 deaths in Greater London in this period 370 (95% confidence interval 328-410) could be attributed to heat. We estimate that 38% of these heat-related deaths could be attributed to the UHI. In the same period is estimate deaths attributable to PM2.5 were 20.6 (10.4-30.8) and to ozone were 52.3 (95% confidence interval 18.6-85.2). Despite not contributing to the record-breaking maximum air temperature observed during this period, the UHI may have contributed to the heatwave's mortality burden through raised nighttime temperature. While air pollutant concentrations were elevated during the period, deaths attributable to air pollution were relatively few compared to deaths attributable to heat.

Temporal variations in the short-term effects of ambient air pollution on cardiovascular and respiratory mortality: a pooled analysis of 380 urban areas over a 22-year period

BACKGROUND

Ambient air pollution, including particulate matter (such as PM10 and PM2·5) and nitrogen dioxide (NO2), has been linked to increases in mortality. Whether populations' vulnerability to these pollutants has changed over time is unclear, and studies on this topic do not include multicountry analysis. We evaluated whether changes in exposure to air pollutants were associated with changes in mortality effect estimates over time.

METHODS

We extracted cause-specific mortality and air pollution data collected between 1995 and 2016 from the Multi-Country Multi-City (MCC) Collaborative Research Network database. We applied a two-stage approach to analyse the short-term effects of NO2, PM10, and PM2·5 on cause-specific mortality using city-specific time series regression analyses and multilevel random-effects meta-analysis. We assessed changes over time using a longitudinal meta-regression with time as a linear fixed term and explored potential sources of heterogeneity and two-pollutant models.

FINDINGS

Over 21·6 million cardiovascular and 7·7 million respiratory deaths in 380 cities across 24 countries over the study period were included in the analysis. All three air pollutants showed decreasing concentrations over time. The pooled results suggested no significant temporal change in the effect estimates per unit exposure of PM10, PM2·5, or NO2 and mortality. However, the risk of cardiovascular mortality increased from 0·37% (95% CI -0·05 to 0·80) in 1998 to 0·85% (0·55 to 1·16) in 2012 with a 10 μg/m3 increase in PM2·5. Two-pollutant models generally showed similar results to single-pollutant models for PM fractions and indicated temporal differences for NO2.

INTERPRETATION

Although air pollution levels decreased during the study period, the effect sizes per unit increase in air pollution concentration have not changed. This observation might be due to the composition, toxicity, and sources of air pollution, as well as other factors, such as socioeconomic determinants or changes in population distribution and susceptibility.

FUNDING

None.

Ambient particulate matter and chronic obstructive pulmonary disease mortality: a nationwide, individual-level, case-crossover study in China

BACKGROUND

Short-term exposure to particulate matter air pollution has been associated with the exacerbations of COPD, but its association with COPD mortality was not fully elucidated. We aimed to assess the association between short-term particulate matter exposure and the risk of COPD mortality in China using individual-level data.

METHODS

We derived 2.26 million COPD deaths from a national death registry database in Chinese mainland between 2013 and 2019. Exposures to fine particulate matter (PM2.5) and coarse particulate matter (PM2.5-10) were assessed by satellite-based models of a 1 × 1 km resolution and assigned to each individual based on residential address. The associations of PM2.5 and PM2.5-10 with COPD mortality were examined using a time-stratified case-crossover design and conditional logistic regressions with distributed lag models. We further conducted stratified analyses by age, sex, education level, and season.

FINDINGS

Short-term exposures to both PM2.5 and PM2.5-10 were associated with increased risks of COPD mortality. These associations appeared and peaked on the concurrent day, attenuated and became nonsignificant after 5 or 7 days, respectively. The exposure-response curves were approximately linear without discernible thresholds. An interquartile range increase in PM2.5 and PM2.5-10 concentrations was associated with 4.23% (95% CI: 3.75%, 4.72%) and 2.67% (95% CI: 2.18%, 3.16%) higher risks of COPD mortality over lag 0-7 d, respectively. The associations of PM2.5 and PM2.5-10 attenuated slightly but were still significant in the mutual-adjustment models. A larger association of PM2.5-10 was observed in the warm season.

INTERPRETATION

This individual-level, nationwide, case-crossover study suggests that short-term exposure to PM2.5 and PM2.5-10 might act as one of the environmental risk factors for COPD mortality.

FUNDING

This study is supported by the National Key Research and Development Program of China (2023YFC3708304 and 2022YFC3702701), the National Natural Science Foundation of China (82304090 and 82030103), the 3-year Action Plan for Strengthening the Construction of the Public Health System in Shanghai (GWVI-11.2-YQ31), and the Science and Technology Commission of Shanghai Municipality (21TQ015).

2024 Guidelines of the Taiwan Society of Cardiology on the Primary Prevention of Atherosclerotic Cardiovascular Disease --- Part I

Atherosclerotic cardiovascular disease (ASCVD) is one of the leading causes of death worldwide and in Taiwan. It is highly prevalent and has a tremendous impact on global health. Therefore, the Taiwan Society of Cardiology developed these best-evidence preventive guidelines for decision-making in clinical practice involving aspects of primordial prevention including national policies, promotion of health education, primary prevention of clinical risk factors, and management and control of clinical risk factors. These guidelines cover the full spectrum of ASCVD, including chronic coronary syndrome, acute coronary syndrome, cerebrovascular disease, peripheral artery disease, and aortic aneurysm. In order to enhance medical education and health promotion not only for physicians but also for the general public, we propose a slogan (2H2L) for the primary prevention of ASCVD on the basis of the essential role of healthy dietary pattern and lifestyles: "Healthy Diet and Healthy Lifestyles to Help Your Life and Save Your Lives". We also propose an acronym of the modifiable risk factors/enhancers and relevant strategies to facilitate memory: " ABC2D2EFG-I'M2 ACE": Adiposity, Blood pressure, Cholesterol and Cigarette smoking, Diabetes mellitus and Dietary pattern, Exercise, Frailty, Gout/hyperuricemia, Inflammation/infection, Metabolic syndrome and Metabolic dysfunction-associated fatty liver disease, Atmosphere (environment), Chronic kidney disease, and Easy life (sleep well and no stress). Some imaging studies can be risk enhancers. Some risk factors/clinical conditions are deemed to be preventable, and healthy dietary pattern, physical activity, and body weight control remain the cornerstone of the preventive strategy.

Spatial and Temporal Distribution Characteristics and Cytotoxicity of Atmospheric PM2.5 in the Main Urban Area of Lanzhou City

PM2.5, as one of the most harmful pollutant in the atmospheric environment and population health, has received much attention. We monitored PM2.5 levels at five sampling sites in the Lanzhou City and collected PM2.5 particles from two representative sites for cytotoxicity experiment. The cytotoxicity of PM2.5 samples on A549 cells and migration ability of the cells were respectively detected by Cell Counting kit-8 (CCK-8) assay and scratch assay. We detected the levels of cellular inflammatory factors and oxidative damage-related biochemical indexes. RT-qPCR was used to detect the mRNA levels of NF-κB and epithelial-mesenchymal transition (EMT)-related genes. We found that the Lanlian Hotel station had the highest PM2.5 annual average concentration. The annual average concentration change curve of PM2.5 showed a roughly "U"-shaped distribution during the whole sampling period. The cytotoxicity experiment showed the viability of A549 cells decreased and the scratch healing rate increased in the 200 and 400 μg/mL PM2.5-treated groups. We also found 400 μg/mL PM2.5 induced changes in the mRNA levels of NF-κB and EMT-related genes, the mRNA levels of IKK-α, NIK, and NF-κB in the 400 μg/mL PM2.5 group were higher than those in the control group. The mRNA levels of E-cadherin decreased and α-SMA increased in the 400 μg/mL PM2.5 groups, and the mRNA levels of Fibronectin increased in the 400 μg/mL PM2.5 groups. Moreover, we found hydroxyl radical scavenging ability and T-AOC levels were lower, and LPO levels were higher in the 200 and 400 μg/mL PM2.5 groups, and the SOD activity of cells in the 400 µg/mL PM2.5 group decreased. And compared with the control group, the levels of TNF-α were higher in the 200 and 400 μg/mL PM2.5 groups and the levels of IL-1 were higher in the 400 μg/mL PM2.5 group. The results indicated that the cytotoxicity of atmospheric PM2.5 was related to oxidative damage, inflammatory response, NF-κB activity and EMT.

Associations between indoor fine particulate matter (PM2.5) and sleep-disordered breathing in an urban sample of school-aged children

OBJECTIVES

Environmental risk factors may contribute to sleep-disordered breathing. We investigated the association between indoor particulate matter ≤2.5µm in aerodynamic diameter (PM2.5) and sleep-disordered breathing in children in an urban US community.

METHODS

The sample consisted of children aged 6-12years living in predominantly low-income neighborhoods in Boston, Massachusetts. Indoor PM2.5 was measured in participants' main living areas for 7days using the Environmental Multipollutant Monitoring Assembly device. High indoor PM2.5 exposure was defined as greater than the sample weekly average 80th percentile level (≥15.6 μg/m3). Sleep-disordered breathing was defined as an Apnea-Hypopnea-Index (AHI) or Oxygen-Desaturation-Index (ODI) (≥3% desaturation) of ≥5 events/hour. Habitual loud snoring was defined as caregiver-report of loud snoring (most or all the time each week) over the past 4weeks. We examined the associations of PM2.5 with sleep-disordered breathing or snoring using logistic regression adjusting for potential confounders.

RESULTS

The sample included 260 children (mean age 9.6years; 41% female), with 32% (n = 76) classified as having sleep-disordered breathing. In a logistic regression model adjusted for socioeconomics and seasonality, children exposed to high indoor PM2.5 levels (n = 53) had a 3.53-fold increased odds for sleep-disordered breathing (95%CI: 1.57, 8.11, p = .002) compared to those with lower indoor PM2.5. This association persisted after additional adjustments for physical activity, outdoor PM2.5, environmental tobacco smoke, and health characteristics. Similar associations were observed for snoring and indoor PM2.5. CONCLUSIONS: Children with higher indoor PM2.5 exposure had greater odds of sleep-disordered breathing and habitual loud snoring, suggesting that indoor air quality contributes to sleep disparities.

Joint Effect of Short-Term Exposure to Fine Particulate Matter and Ozone on Mortality: A Time Series Study in 272 Chinese Cities

Short-term exposure to PM2.5 or O3 can increase mortality risk; however, limited studies have evaluated their interaction. A multicity time series study was conducted to investigate the synergistic effect of PM2.5 and O3 on mortality in China, using mortality data and high-resolution pollutant predictions from 272 cities in 2013-2015. Generalized additive models were applied to estimate associations of PM2.5 and O3 with mortality. Modification and interaction effects were explored by stratified analyses and synergistic indexes. Deaths attributable to PM2.5 and O3 were evaluated with or without modification of the other pollutant. The risk of total nonaccidental mortality increased by 0.70% for each 10 μg/m3 increase in PM2.5 when O3 levels were high, compared to 0.12% at low O3 levels. The effect of O3 on total nonaccidental mortality at high PM2.5 levels (1.26%) was also significantly higher than that at low PM2.5 levels (0.59%). Similar patterns were observed for cardiovascular or respiratory diseases. The relative excess risk of interaction and synergy index of PM2.5 and O3 on nonaccidental mortality were 0.69% and 1.31 with statistical significance, respectively. Nonaccidental deaths attributable to short-term exposure of PM2.5 or O3 when considering modification of the other pollutant were 28% and 31% higher than those without considering modification, respectively. Our results found synergistic effects of short-term coexposure to PM2.5 and O3 on mortality and suggested underestimations of attributable risks without considering their synergistic effects.

Air quality assessment of a mass deployment of microgrids

Microgrids are emerging to mitigate the degradation in grid resiliency and reliability resulting from an increasing frequency of grid outages. Because microgrids incorporate a local source of power generation, the production of electricity is shifting from a centralized to distributed topology, thereby installing power generation resources and the concomitant emissions into heavily populated urban air sheds and residential communities. In this paper, the air quality and public health impacts of a mass deployment of microgrids in an urban air shed are assessed. Candidates to become microgrids are identified for both the near- and long-term deployment, and two microgrid scenarios are considered, differing by the 24/7 prime source of power: (1) combustion gas turbine (CGT)-based microgrids and (2) zero-emission fuel cell (FC)-based microgrids complemented by solar PV and battery energy storage. Spatially and temporally resolved emissions from the microgrids are input to an air quality model and assessed for health impacts. The results show that (1) a mass deployment of CGT-based or FC-based microgrids in both the near- and long-term has a relatively small impact on air quality, (2) the health impacts are nonetheless significant for CGT-based microgrids due to the large and dense population of the area, and (3) disadvantaged communities are disproportionately impacted with the deployment of CTG-based microgrids. For example, near-term deployment of CGT-based microgrids results in an increase in the incidence of premature mortality (1 to 5 incidences per month) and an increase of $33 to $56 million per month in health costs. Deploying zero-emission FC-based microgrids mitigates the adverse health impact, prevents several incidences of premature mortality, and results in saving of ~$36M per month rather than a cost per month of ~$50M.

Does diet quality moderate the long-term effects of discrete but extreme PM2.5 exposure on respiratory symptoms? A study of the Hazelwood coalmine fire

In 2014, a fire at an open cut coalmine in regional Victoria, Australia burned for 6 weeks. Residents of the nearby town of Morwell were exposed to smoke, which included high levels of fine particulate matter (PM2.5). We investigated whether the long-term effects of PM2.5 on respiratory health were moderated by diet quality. A cross-sectional analysis was conducted of data collected 8.5 years after the mine fire from 282 residents of Morwell and 166 residents from the nearby unexposed town of Sale. Primary outcomes were respiratory symptoms. Exposure was coalmine fire-related PM2.5 and diet quality was assessed as Australian Recommended Food Score (ARFS) derived using the Australian Eating Survey (AES). The moderating effect of diet quality on respiratory outcomes associated with PM2.5 was assessed using logistic regression models, adjusting for potential confounders. Diet quality was poor in this sample, with 60% in the lowest category of overall diet quality. Overall diet quality and fruit and vegetable quality significantly attenuated the association between PM2.5 and prevalence of chronic cough and phlegm. Sauce/condiment intake was associated with a greater effect of PM2.5 on COPD prevalence. No other moderating effects were significant. The moderating effects of overall diet quality and vegetable and fruit intake aligned with a priori hypotheses, suggesting potential protective benefits. While more evidence is needed to confirm these findings, improving diets, especially fruit and vegetable intake, may provide some protection against the effects of smoke exposure from fire events.

Exploring the association between ambient air pollution and COVID-19 risk: A comprehensive meta-analysis with meta-regression modelling

Introduction

Air pollution is speculated to increase the risk of Coronavirus disease-2019 (COVID-19). Nevertheless, the results remain inconsistent and inconclusive. This study aimed to explore the association between ambient air pollution (AAP) and COVID-19 risks using a meta-analysis with meta-regression modelling.

Methods

The inclusion criteria were: original studies quantifying the association using effect sizes and 95 % confidence intervals (CIs); time-series, cohort, ecological or case-crossover peer-reviewed studies in English. Exclusion criteria encompassed non-original studies, animal studies, and data with common errors. PubMed, Web of Science, Embase and Google Scholar electronic databases were systemically searched for eligible literature, up to 31, March 2023. The risk of bias (ROB) was assessed following the Agency for Healthcare Research and Quality parameters. A random-effects model was used to calculate pooled risk ratios (RRs) and their 95 % CIs.

Results

A total of 58 studies, between 2020 and 2023, met the inclusion criteria. The global representation was skewed, with major contributions from the USA (24.1 %) and China (22.4 %). The distribution included studies on short-term (43.1 %) and long-term (56.9 %) air pollution exposure. Ecological studies constituted 51.7 %, time-series-27.6 %, cohorts-17.2 %, and case crossover-3.4 %. ROB assessment showed low (86.2 %) and moderate (13.8 %) risk. The COVID-19 incidences increased with a 10 μg/m3 increase in PM2.5 [RR = 4.9045; 95 % CI (4.1548-5.7895)], PM10 [RR = 2.9427: (2.2290-3.8850)], NO2 [RR = 3.2750: (3.1420-3.4136)], SO2 [RR = 3.3400: (2.7931-3.9940)], CO [RR = 2.6244: (2.5208-2.7322)] and O3 [RR = 2.4008: (2.1859-2.6368)] concentrations. A 10 μg/m3 increase in concentrations of PM2.5 [RR = 3.0418: (2.7344-3.3838)], PM10 [RR = 2.6202: (2.1602-3.1781)], NO2 [RR = 3.2226: (2.1411-4.8504)], CO [RR = 1.8021 (0.8045-4.0370)] and O3 [RR = 2.3270 (1.5906-3.4045)] was significantly associated with COVID-19 mortality. Stratified analysis showed that study design, exposure period, and country influenced exposure-response associations. Meta-regression model indicated significant predictors for air pollution-COVID-19 incidence associations.

Conclusion

The study, while robust, lacks causality demonstration and focuses only on the USA and China, limiting its generalizability. Regardless, the study provides a strong evidence base for air pollution-COVID-19-risks associations, offering valuable insights for intervention measures for COVID-19.

The effect of temperature on infectious diarrhea disease: A systematic review

This study aimed to ascertain the delayed effects of various exposure temperatures on infectious diarrhea. We performed a Bayesian random-effects network meta-analysis to calculate relative risks (RR) with 95 % confidence intervals (95 % CI). The heterogeneity was analyzed by subgroup analysis. There were 25 cross-sectional studies totaling 6858735 patients included in this analysis, with 12 articles each investigating the effects of both hyperthermia and hypothermia. Results revealed that both high temperature (RRsingle = 1.22, 95%CI:1.04-1.44, RRcum = 2.96, 95%CI:1.60-5.48, P < 0.05) and low temperature (RRsingle = 1.17, 95%CI:1.02-1.37, RRcum = 2.19, 95%CI:1.33-3.64, P < 0.05) significantly increased the risk of infectious diarrhea, while high temperature caused greater. As-sociations with strengthening in bacillary dysentery were found for high temperatures (RRcum = 2.03, 95%CI:1.41-3.01, P < 0.05; RRsingle = 1.17, 95%CI:0.90-1.62, P > 0.05), while the statistical significance of low temperatures in lowering bacterial dysentery had vanished. This investigation examined that high temperature and low temperature were the conditions that posed the greatest risk for infectious diarrhea. This research offers fresh perspectives on preventing infectious diarrhea and will hopefully enlighten future studies on the impact of temperature management on infectious diarrhea.

Major source categories of PM2.5 oxidative potential in wintertime Beijing and surroundings based on online dithiothreitol-based field measurements

Fine particulate matter (PM2.5) causes millions of premature deaths each year worldwide. Oxidative potential (OP) has been proposed as a better metric for aerosol health effects than PM2.5 mass concentration alone. In this study, we report for the first time online measurements of PM2.5 OP in wintertime Beijing and surroundings based on a dithiothreitol (DTT) assay. These measurements were combined with co-located PM chemical composition measurements to identify the main source categories of aerosol OP. In addition, we highlight the influence of two distinct pollution events on aerosol OP (spring festival celebrations including fireworks and a severe regional dust storm). Source apportionment coupled with multilinear regression revealed that primary PM and oxygenated organic aerosol (OOA) were both important sources of OP, accounting for 41 ± 12 % and 39 ± 10 % of the OPvDTT (OP normalized by the sampled air volume), respectively. The small remainder was attributed to fireworks and dust, mainly resulting from the two distinct pollution events. During the 3.5-day spring festival period, OPvDTT spiked to 4.9 nmol min-1 m-3 with slightly more contribution from OOA (42 ± 11 %) and less from primary PM (31 ± 15 %). During the dust storm, hourly-averaged PM2.5 peaked at a very high value of 548 μg m-3 due to the dominant presence of dust-laden particles (88 % of total PM2.5). In contrast, only mildly elevated OPvDTT values (up to 1.5 nmol min-1 m-3) were observed during this dust event. This observation indicates that variations in OPvDTT cannot be fully explained using PM2.5 alone; one must also consider the chemical composition of PM2.5 when studying aerosol health effects. Our study highlights the need for continued pollution control strategies to reduce primary PM emissions, and more in-depth investigations into the source origins of OOA, to minimize the health risks associated with PM exposure in Beijing.

Hidden danger: The long-term effect of ultrafine particles on mortality and its sociodemographic disparities in New York State

Although previous studies have shown increased health risks of particulate matters, few have evaluated the long-term health impacts of ultrafine particles (UFPs or PM0.1, ≤ 0.1 µm in diameter). This study assessed the association between long-term exposure to UFPs and mortality in New York State (NYS), including total non-accidental and cause-specific mortalities, sociodemographic disparities and seasonal trends. Collecting data from a comprehensive chemical transport model and NYS Vital Records, we used the interquartile range (IQR) and high-level UFPs (≥75 % percentile) as indicators to link with mortalities. Our modified difference-in-difference model controlled for other pollutants, meteorological factors, spatial and temporal confounders. The findings indicate that long-term UFPs exposure significantly increases the risk of non-accidental mortality (RR=1.10, 95 % CI: 1.05, 1.17), cardiovascular mortality (RR=1.11, 95 % CI: 1.05, 1.18) particularly for cerebrovascular (RR=1.21, 95 % CI: 1.10, 1.35) and pulmonary heart diseases (RR=1.33, 95 % CI: 1.13, 1.57), and respiratory mortality (borderline significance, RR=1.09, 95 % CI: 1.00, 1.18). Hispanics (RR=1.13, 95 % CI: 1.00, 1.29) and non-Hispanic Blacks (RR=1.40, 95 % CI: 1.16, 1.68) experienced significantly higher mortality risk after exposure to UFPs, compared to non-Hispanic Whites. Children under five, older adults, non-NYC residents, and winter seasons are more susceptible to UFPs' effects.

Challenges of Air Pollution and Health in East Asia

PURPOSE OF REVIEW

Air pollution has been a serious environmental and public health issue worldwide, particularly in Asian countries. There have been significant increases in epidemiological studies on fine particulate matter (PM2.5) and ozone pollution in East Asia, and an in-depth review of epidemiological evidence is urgent. Thus, we carried out a systematic review of the epidemiological research on PM2.5 and ozone pollution in East Asia released in recent years.

RECENT FINDINGS

Recent studies have indicated that PM2.5 and ozone are the most detrimental air pollutants to human health, resulting in substantial disease burdens for Asian populations. Many epidemiological studies of PM2.5 and ozone have been mainly performed in three East Asian countries (China, Japan, and South Korea). We derived the following summary findings: (1) both short-term and long-term exposure to PM2.5 and ozone could raise the risks of mortality and morbidity, emphasizing the need for continuing improvements in air quality in East Asia; (2) the long-term associations between PM2.5 and mortality in East Asia are comparable to those observed in Europe and North America, whereas the short-term associations are relatively smaller in magnitude; and (3) further cohort and intervention studies are required to yield robust and precise evidence that can promote evidence-based policymaking in East Asia. This updated review presented an outline of the health impacts of PM2.5 and ozone in East Asia, which may be beneficial for the development of future regulatory policies and standards, as well as for designing subsequent investigations.

Hotspot driven air pollution during crop residue burning season in the Indo-Gangetic Plain, India

Intensive crop residue burning (CRB) in northern India triggers severe air pollution episodes over the Indo-Gangetic Plain (IGP) each year during October and November. We have quantified the contribution of hotspot districts (HSDs) and total CRB to poor air quality over the IGP. Initially, we investigated the spatiotemporal distribution of CRB fire within the domain and pinpointed five HSD in each Punjab and Haryana. Furthermore, we have simulated air quality and quantified the impact of CRB using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), incorporating recent anthropogenic emissions (EDGAR v5) and biomass burning emissions (FINN v2.4) inventories, along with MOZART-MOSAIC chemistry. The key finding is that HSDs contributed ∼80% and ∼50% of the total fire counts in Haryana and Punjab, respectively. The model effectively captured observed PM₂.₅ concentrations, with a normalized mean bias (NMB) below 0.2 and R-squared (R2) exceeding 0.65 at the majority of validation sites. However, some discrepancies were observed at a few sites in Delhi, Punjab, Haryana, and West Bengal. The National Capital Region experienced the highest PM₂.₅ concentrations, followed by Punjab, Haryana, Uttar Pradesh, Bihar, and West Bengal. Moreover, HSDs were responsible for about 70% of the total increase in CRB-induced PM₂.₅ in the western, central, and eastern cities, and around 50% in the northern cities. By eliminating CRB emissions across the domain, we could potentially save approximately 18,000 lives annually. Policymakers, scientists, and institutions can leverage the framework to address air pollution at national and global scales by targeting source-specific hotspots. This approach, coupled with appropriate technological and financial solutions, can contribute to achieving climate change and sustainable development goals.

Health and economic cost estimates of short-term total and wildfire PM2.5 exposure on work loss: using the consecutive California Health Interview Survey (CHIS) data 2015-2018

Instruction

To help determine the health protectiveness of government regulations and policies for air pollutant control for Americans, our study aimed to investigate the health and economic impacts of work loss due to sickness associated with daily all-source and wildfire-specific PM2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 μm) exposures in California.

Methods

We linked the 2015-2018 California Health Interview Survey respondents' geocoded home addresses to daily PM2.5 estimated by satellites and atmospheric modelling simulations and wildfire-related PM2.5 from Community Multiscale Air Quality models. We calculated and applied the coefficient for the association between daily PM2.5 exposure and work loss from regression analyses to the Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) platform to assess the health and economic impacts of PM2.5 exposure on work loss due to sickness.

Results

We observed that each 1 µg/m3 increase in daily total PM2.5 exposure will lead to about 1 million days of work loss per year ranging from 1.1 to 1.6 million person-days, and the related economic loss was $310-390 million. Wildfire smoke alone could contribute to 0.7-2.6 million work-loss days with a related economic loss of $129-521 million per year in 2015-2018. Using the function coefficient in the current BenMAP, the excess work-loss days due to sickness was about 250 000 days and the estimated economic loss was about $45-50 million for each 1 µg/m3 increase in daily total PM2.5 exposure, and wildfire smoke alone would lead to 0.17-0.67 million work-loss days with related economic loss of $31-128 million per year during the same period.

Conclusions

Both conventional and wildfire-specific sources of PM2.5 produced substantial work loss and cost in California. Updating the current BenMAP-CE calculations for work-loss days will be essential in quantifying the current health impacts of PM2.5 to help inform the policies and regulations to protect public health.

Fine particulate matter-sudden death association modified by ventricular hypertrophy and inflammation: a case-crossover study

Background

Sudden death accounts for approximately 10% of deaths among working-age adults and is associated with poor air quality. Objectives: To identify high-risk groups and potential modifiers and mediators of risk, we explored previously established associations between fine particulate matter (PM2.5) and sudden death stratified by potential risk factors.

Methods

Sudden death victims in Wake County, NC, from 1 March 2013 to 28 February 2015 were identified by screening Emergency Medical Systems reports and adjudicated (n = 399). Daily PM2.5 concentrations for Wake County from the Air Quality Data Mart were linked to event and control periods. Potential modifiers included greenspace metrics, clinical conditions, left ventricular hypertrophy (LVH), and neutrophil-to-lymphocyte ratio (NLR). Using a case-crossover design, conditional logistic regression estimated the OR (95%CI) for sudden death for a 5 μg/m3 increase in PM2.5 with a 1-day lag, adjusted for temperature and humidity, across risk factor strata.

Results

Individuals having LVH or an NLR above 2.5 had PM2.5 associations of greater magnitude than those without [with LVH OR: 1.90 (1.04, 3.50); NLR > 2.5: 1.25 (0.89, 1.76)]. PM2.5 was generally less impactful for individuals living in areas with higher levels of greenspace.

Conclusion

LVH and inflammation may be the final step in the causal pathway whereby poor air quality and traditional risk factors trigger arrhythmia or myocardial ischemia and sudden death. The combination of statistical evidence with clinical knowledge can inform medical providers of underlying risks for their patients generally, while our findings here may help guide interventions to mitigate the incidence of sudden death.

Effect of Exposure to Particulate Matter on the Ocular Surface in an Experimental Allergic Eye Disease Mouse Model

In response to the escalating concern over the effect of environmental factors on ocular health, this study aimed to investigate the impact of air pollution-associated particulate matter (PM) on ocular allergy and inflammation. C57BL/6 mice were sensitized with ovalbumin (OVA) topically and aluminum hydroxide via intraperitoneal injection. Two weeks later, the mice were challenged with OVA and exposed to PM. Three groups-naive, OVA, and OVA-sensitized with PM exposure (OVA + PM) groups-were induced to an Allergic Eye disease (AED) model. Parameters including clinical signs, histological changes, inflammatory cell infiltration, serum OVA-specific immunoglobulins E (IgE) levels, mast cells degranulation, cellular apoptosis and T-cell cytokines were studied. The results demonstrate that exposure with PM significantly exacerbates ocular allergy, evidenced by increased eye-lid edema, mast cell degranulation, inflammatory cytokines (IL-4, IL-5 and TNF-α), cell proliferation (Ki67), and serum IgE, polymorphonuclear leukocytes (PMN), and apoptosis and reduced goblet cells. These findings elucidate the detrimental impact of PM exposure on exacerbating the severity of AED. Noticeably, diminished goblet cells highlight disruptions in ocular surface integrity, while increased PMN infiltration with an elevated production of IgE signifies a systemic allergic response with inflammation. In conclusion, this study not only scientifically substantiates the association between air pollution, specifically PM, and ocular health, but also underscores the urgency for further exploration and targeted interventions to mitigate the detrimental effects of environmental pollutants on ocular surfaces.