Land use and air quality in urban environments: Human health risk assessment due to inhalation of airborne particles

Fine particle trace elements at a mountain site in southern China: Source identification, transport, and health risks

Trace elements in atmospheric particulate matter play a significant role in air quality, human health, and biogeochemical cycles. In this study, the trace elements (Ca, Al, K, Fe, Na, Mg, Zn, Pb, Mn, Ti, Cu, Cr, Sr, Ni) in PM2.5 samples collected at the summit of Mt. Lushan were analyzed to quantify their abundance, source, transport, and health risks. During the whole sampling period, the major trace elements was Ca, Al, and K. While the trace metals with the lowest concentrations were Sr, Ni, Rb, and Cd. The trace elements were influenced by air mass transport routes, exhibiting an increasing trend of crustal elements in the northwesterly airmass and anthropogenic elements (Zn, Mn, Cu, and Ni) in the easterly air masses. Construction dust, coal + biomass burning, vehicle emission, urban nitrate-rich + urban waste incineration emissions, and soil dust + industry emissions were common sources of PM2.5 on Mt. Lushan. Different air mass transport routes had various source contribution patterns. These results indicate that trace elements at Mt. Lushan are influenced by regional anthropogenic emissions and monsoon-dominated trace element transport. The total resulting cancer risk value that these elements posed were below the acceptable risk value of 1 × 10-6, while the non-carcinogenic risk value (1.72) was higher than the safety level, suggesting that non-carcinogenic effects due to these trace elements inhalation were likely to occur. Vehicle emission and coal + biomass burning were the common dominant sources of non-cancer risks posed by trace elements at Mt. Lushan.

Determination of the maximum bioaccumulation capacity of various metals in leaves of two Tillandsia species

Tillandsia species are plants from the Bromeliaceae family which display biomonitoring capacities in both active and passive modes. The bioaccumulation potential of Tillandsia aeranthos (Loisiel.) Desf. and Tillandsia bergeri Mez acclimated to Southern/Mediterranean Europe has never been studied. More generally, few studies have detailed the maximum accumulation potential of Tillandsia leaves through controlled experiments. The aim of this study is to evaluate the maximum accumulation values of seven metals (Co, Cu, Mn, Ni, Pb, Pt, and Zn) in T. aeranthos and T. bergeri leaves. Plants were immersed in different mono elemental metallic solutions of Co (II), Cu (II), Mn (II), Ni (II), Pb (II), Pt (IV), and Zn (II) ions at different concentrations. In addition, cocktail solutions of these seven metals at different concentrations were prepared to study the main differences and the potential selectivity between metals. After exposure, the content of these metals in the leaves were measured by inductively coupled plasma-optical emission spectrometry. Data sets were evaluated by a fitted regression hyperbola model and principal component analysis, maximum metal loading capacity, and thermodynamic affinity constant were determined. The results showed important differences between the two species, with T. bergeri demonstrating higher capacity and affinity for metals than T. aeranthos. Furthermore, between the seven metals, Pb and Ni showed higher enrichment factors (EF). T. bergeri might be a better bioaccumulator than T. aeranthos with marked selectivity for Pb and Ni, metals of concern in air quality biomonitoring.

Atmospheric pollution by potentially toxic elements: measurement and risk assessment using lichen transplants

The lichen Usnea articulata collected from an unpolluted area was exposed for 6 months at 26 sites for the sample chosenusing a stratified random design, and the content of potentially toxic elements (PTEs) including As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn, was assessed using ICP-MS. The health risk for both adults and children was then calculated using the PTEs concentrations. The results showed that despite the hostile urban conditions, transplanted lichens depicted clear deposition patterns of airborne PTEs, mostly associated with industrial sites, where As and other elements showed remarkably high values. The cumulative hazard index was below the risk threshold, both for adults and children. For the entire population (particularly children) residing in areas surrounding industrial sites, As and Cr appeared to be potentially carcinogenic elements.

Global plastic upcycling during and after the COVID-19 pandemic: The status and perspective

Plastic pollution has become one of the most pressing environmental issues worldwide since the vast majority of post-consumer plastics are hard to degrade in the environment. The coronavirus disease (COVID-19) pandemic had disrupted the previous effort of plastic pollution mitigation to a great extent due to the overflow of plastic-based medical waste. In the post-pandemic era, the remaining challenge is how to motivate global action towards a plastic circular economy. The need for one package of sustainable and systematic plastic upcycling approaches has never been greater to address such a challenge. In this review, we summarized the threat of plastic pollution during COVID-19 to public health and ecosystem. In order to solve the aforementioned challenges, we present a shifting concept, regeneration value from plastic waste, that provides four promising pathways to achieve a sustainable circular economy: 1) Increasing reusability and biodegradability of plastics; 2) Transforming plastic waste into high-value products by chemical approaches; 3) The closed-loop recycling can be promoted by biodegradation; 4) Involving renewable energy into plastic upcycling. Additionally, the joint efforts from different social perspectives are also encouraged to create the necessary economic and environmental impetus for a circular economy.

Cumulative Impacts of Diverse Land Uses in British Columbia, Canada: Application of the "EnviroScreen" Method

(1) Objectives: Cumulative impacts refer to the legacies of land use decisions on environmental, community and health values. New integrative impact assessment tools are required to assess cumulative impacts on diverse values to meet sustainability goals in the 21st century. In this contribution, the CalEnviroScreen methodology-a screening tool capable of merging environmental, socioeconomic and health data-is applied to Local Health Areas in British Columbia, Canada. (2) Methods: The CalEnviroScreen is a method that standardizes environmental, socioeconomic and health data to depict an indicator's percentile rank in the distribution of all units of analysis. The method combines indicators to measure four dimensions of pressure: environmental exposures, environmental effects, socioeconomic conditions, and sensitive populations (i.e., health outcomes). We create two versions of EnviroScreen: one following the CalEnviroScreen suite of indicators, and another that uses nuanced indicators to approximate the realities of industrial land uses present in British Columbia. BCEnviroScreen scores are plotted by race/ethnicity to understand potential racial inequities in cumulative exposures. (3) Results: The BCEnviroScreen has a greater likelihood of quantifying the cumulative impacts of diverse industries and land uses present across resource-dependent parts of the province, relative to the more urban-centric CalEnviroScreen indicator suite. Analyzing the distribution of BCEnviroScreen scores by race/ethnicity suggests that visible minority populations may be inequitably exposed to cumulative impacts in BC. (4) Conclusion: EnviroScreen tools hold significant potential to influence Canadian environmental health policy. This research demonstrates the applicability of the tool to British Columbia and other jurisdictions, illustrates how indicators can be tailored to better represent regional context, and shows how the tool can be used to screen for potential environmental health injustices.

Effects of airway deformation and alveolar pores on particle deposition in the lungs

The distal lung (G14-G23), which are composed of alveoli and bronchi, are responsible for almost all gas exchange and micro- and nanoparticle deposition in the lungs. In the existing research using computational fluid dynamics, the geometric modeling accuracy of the bronchial bifurcation structure is given priority, and then the alveoli are attached to bronchi as discrete spherical crowns. This method ignores the correlation between alveoli. In fact, the alveoli have a tessellated distribution, and adjacent alveoli are connected by several alveolar pores. Due to the huge number of alveoli, this seemingly small difference will be greatly amplified, which may lead to a large deviation in the prediction of the overall flow. Accordingly, the objective of this study is to construct a two-dimensional distal lung model including the bronchi, acini, and alveolar pores by using the methods of regular hexagonal tessellational subdivision, fusion, and coordinate transformation. A moving boundary is introduced to simulate the process of airflow and particle deposition in the distal lung, and the effects of bronchial deformation, respiratory frequency, and alveolar pores are obtained. The results show that there are significant differences in intrapulmonary flow patterns with and without alveolar pores. Alveolar pores can establish bypass ventilation downstream of a blockage, thus providing a pathway for particles to enter the airways downstream of the blockage. Changing the respiratory frequency and the amplitude of bronchial deformation will change the relative velocity between particles and moving wall, which, in turn, will change the particle deposition efficiency in the distal lung. To summarize this study, a geometric modeling method for the distal lung with alveolar pores is established, and the important roles of detailed characteristics of the distal lung are revealed. The findings of this study provide a reasonable hydrodynamic mechanism for the prevention of related respiratory diseases.

The effect of national protest in Ecuador on PM pollution

Particulate matter (PM) accounts for millions of premature deaths in the human population every year. Due to social and economic inequality, growing human dissatisfaction manifests in waves of strikes and protests all over the world, causing paralysis of institutions, services and circulation of transport. In this study, we aim to investigate air quality in Ecuador during the national protest of 2019, by studying the evolution of PM_2.5 (PM ≤ 2.5 µm) concentrations in Ecuador and its capital city Quito using ground based and satellite data. Apart from analyzing the PM_2.5 evolution over time to trace the pollution changes, we employ machine learning techniques to estimate these changes relative to the business-as-usual pollution scenario. In addition, we present a chemical analysis of plant samples from an urban park housing the strike. Positive impact on regional air quality was detected for Ecuador, and an overall − 10.75 ± 17.74% reduction of particulate pollution in the capital during the protest. However, barricade burning PM peaks may contribute to a release of harmful heavy metals (tire manufacture components such as Co, Cr, Zn, Al, Fe, Pb, Mg, Ba and Cu), which might be of short- and long-term health concerns.

Health risk assessment of heavy metals in soils and screening of accumulating plants around the Wanshan mercury mine in Northeast Guizhou Province, China

The Wanshan mercury mine, which is an abandoned mine located in northeastern Guizhou Province in Southwest China, has introduced serious Hg pollution to the local ecosystem resulting from previous mining and smelting activities. However, it is not clear to date whether soil pollution has actually improved after treatment by related departments. Therefore, the present study investigates the vegetation community and heavy metal contents of the soil and plants in the Wanshan mercury mining area. The results showed that most of Hg, Cd, As, Cu, and Zn contents in soil samples were higher than those of Soil Environment Quality Risk Control Standard for Soil Contamination of Agricultural Land in China (GB15618-2018). The observed plant species mainly consisted of Compositae, followed by Leguminosae. Unfortunately, this investigation found that heavy metal concentrations in these plants were not extremely high and far below the standard of hyperaccumulator. Despite all this, the maximum values of bioaccumulation factor for Pb, Cd, Hg, As, Cu and Zn were Serissa japonica (Thunb.) Thunb., Rhus chinensis Mill., Potentilla sibbaldii Haller f., Erigeron canadensis L., Clerodendrum bungei var. bungei. and Rhus chinensis Mill., respectively. Regardless of the carcinogenic or noncarcinogenic risk index, the potential risk to urban children is higher. Our results suggest that heavy metal pollution was indeed relieved since their contents in soil significantly decreased in comparison with those reported in other previous studies. This finding provides a reference for the long-term treatment of heavy metal pollution in the local environment and other areas employing analogous environmental protection measures.

Source Apportionment and Health Risk Assessment of Metal Elements in PM2.5 in Central Liaoning’s Urban Agglomeration

To better understand the source and health risk of metal elements in PM2.5, a field study was conducted from May to December 2018 in the central region of the Liaoning province, China, including the cities of Shenyang, Anshan, Fushun, Benxi, Yingkou, Liaoyang, and Tieling. 24 metal elements (Na, K, V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sn, Sb, Pb, Bi, Al, Sr, Mg, Ti, Ca, Fe, Ba, and Si) in PM2.5 were measured by ICP-MS and ICP-OES. They presented obvious seasonal variations, with the highest levels in winter and lowest in summer for all seven cities. The sum of 24 elements were ranged from to in these cities. The element mass concentration ratio was the highest in Yingkou in the spring (26.15%), and the lowest in Tieling in winter (3.63%). The highest values of elements in PM2.5 were mostly found in Anshan and Fushun among the studied cities. Positive matrix factorization (PMF) modelling revealed that coal combustion, industry, traffic emission, soil dust, biomass burning, and road dust were the main sources of measured elements in all cities except for Yingkou. In Yingkou, the primary sources were identified as coal combustion, metal smelting, traffic emission, soil dust, and sea salt. Health risk assessment suggested that Mn had non-carcinogenic risks for both adults and children. As for Cr, As, and Cd, there was carcinogenic risks for adults and children in most cities. This study provides a clearer understanding of the regional pollution status of industrial urban agglomeration.

Geochemical characteristics of trace elements in size-resolved coastal urban aerosols associated with distinct air masses over tropical peninsular India: Size distributions and source apportionment

Trace elements in atmospheric particulate matter play a significant role in air quality, health and biogeochemical cycles. The present study reports on geochemical characteristics of size-resolved trace elements in PM₁₀ aerosols collected under different air masses over a coastal urban location in peninsular India. A contrast in elemental distribution was observed for the particle size above 7.0 μm and below 1.1 μm under the influence of northeasterly air masses as characterized by Al > Fe > Zn and Fe > Al > Zn, respectively. The concentrations of the crustal elements (Al, Fe, Ti, P, Ba, Co) were high and illustrated by a unimodal size distribution with a peak in coarse mode (>2.0 μm) during northwesterly air masses. On the other hand, combustion-derived metals (Cu, Zn, Cd, Sb, and Pb) were maximized under northeasterly air masses, characterized by unimodal size distribution with a peak in fine mode (<2.0 μm). The enrichment factor (EF) analysis reveals the contribution of anthropogenic emissions to Cd, Sb, Pb, Zn, Cu, Cr, Ni, As, and Sn metals, particularly to the high enrichment of trace metals in fine mode. These results suggest that crustal emissions are major sources of trace metals in coarse mode aerosols; whereas combustion derived anthropogenic emissions contribute to the fine mode aerosols. The positive matrix factorization (PMF) analysis revealed that crustal sources (52-90%) were most abundant for particles >7.0 μm, whereas combustion related emissions such as vehicular and traffic sources are predominant for particles <1.1 μm. The present study demonstrates that trace metals in coastal urban aerosols are affected by changes in emission sources/strengths and regional transport of air masses originated from the northeasterly and northwesterly parts of the tropical Indian subcontinent.

Inter- and intra-city comparisons of PM2.5 concentration changes under COVID-19 social distancing in seven major cities of South Korea

The COVID-19 pandemic has prompted governments around the world to impose mitigation strategies of unprecedented scales, typically involving some form of restrictions on social activities and transportation. The South Korean government has been recommending a collection of guidelines now known as social distancing, leading to reduced human activities. This study analyzes changes in the concentrations of fine particulate matter (PM_2.5) during the 30-day periods before and since the start of social distancing on 29 February 2020 using measurement data from air quality monitoring stations at various locations of the seven major cities of South Korea, namely, Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, and Ulsan. All seven cities experienced decreased levels of PM_2.5 concentration by up to 25% and smaller fluctuations during the period of social distancing. Inter-city comparisons show that the PM_2.5 concentration changes are positively correlated with the city-wide PM_2.5 emission fractions for mobile sources and negatively correlated with the city-wide PM_2.5 emission fractions for combustion and industrial process sources. In addition, the meteorological influences favorable for transboundary pollutant transport have weakened during the period under COVID-19 social distancing. Intra-city comparisons show that decreases in the intra-city variability of PM_2.5 concentration were larger in coastal cities than in inland cities. Comparisons between the inter- and intra-city variabilities in the PM_2.5 concentration changes under social distancing highlight the importance of taking into account intra-city variabilities in addition to inter-city variabilities.

Evaluating the size distribution characteristics and sources of atmospheric trace elements at two mountain sites: comparison of the clean and polluted regions in China

Size-resolved trace metal concentrations at two background sites were assessed during a 1-year observation campaign, with the measurements performed in parallel at two mountain sites, where Mt. Dinghu (DHS) located in the rural region of Pearl River Delta (PRD) and Mt. Gongga (GGS) located in the Tibetan Plateau region. In total, 15 selected trace elements (Mg, Al, K, V, Mn, Fe, Cu, Zn, As, Mo, Ag, Cd, Ba, Tl, and Pb) in aerosol samples were determined using inductively coupled plasma mass spectrometry (ICPMS). The major metals in these two mountain sites were Fe, K, Mg, and Ca with concentrations ranging between 241 and 1452 ng/m³, 428 and 1351 ng/m³, 334 and 875 ng/m³, and 376 and 870 ng/m³, respectively, while the trace metals with the lowest concentrations were Mo, Ag, Cd, and Tl with concentrations lower than 4 ng/m³ in DHS and 2 ng/m³ in GGS. The pronounced seasonal variability in the trace elements was observed in DHS, with lower concentrations in spring and summer and relatively high in winter and autumn, whereas seasonal variance of trace elements is hardly observed in Mt. Gongga. The size distribution pattern of crustal elements of Al, Mg, K, Ba, and Fe was quite similar in DHS and GGS, which were mainly found in coarse particles peaked at 4.7-5.8 μm. In addition, V, Mo, Ag, and Tl were also concentrated in coarse particles, although the high enrichment factor (EF > 100) of which suggested anthropogenic origin, whereas trace metals of Cd, Mn, Zn, As, Cu, and Pb concentrated in fine mode particles. Specifically, these trace metals peak at approximately 1.5 μm in DHS, while those in GGS peaked at diameter smaller than 0.3 μm, indicating the responsible for long-range transport from the far urban and industrialized areas. Multivariate receptor model combined with the enrichment factor results demonstrated that the trace elemental components at these two background sites were largely contributed from the fossil fuel combustion (55.4% in DHS and 44.0% in GGS) and industrial emissions factors (20.1% vs. 26.5%), which are associated with long distance transport from the coastal area of Southeast China and the Northwestern India, respectively, as suggested by the backward air mass trajectory analysis. Local sources from soil dust contributed a minor variance for trace elements in DHS (9.7%) and GGS (13.8%), respectively.

PM10-bound trace elements in the Great Lakes Basin (1988-2017) indicates effectiveness of regulatory actions, variations in sources and reduction in human health risks

Limited studies focus on the effectiveness of regulatory actions on changes in sources and temporal trends of human health risks for trace elements in atmospheric particles < 10 μm (PM₁₀). To address this knowledge gap, PM₁₀ samples were collected at three stations in the Great Lakes Basin over a thirty-year time span and analyzed for 19 representative elements. Temporal trends of trace elements in PM₁₀ were derived using the Digital Filtration Technique and sources of these elements were determined using multiple statistical techniques, namely enrichment factor analysis, positive matrix factorization (PMF) and potential source contribution function (PSCF). Non-carcinogenic and carcinogenic risks by chronic exposure were assessed using US EPA reference concentrations and inhalation unit risk. Our results showed a strong relationship between element concentrations and local populations, which suggested that the emissions of trace elements were anthropogenically-related and was confirmed by the enrichment factor analysis. The concentrations of most elements were significantly decreasing with halving times ranging from 10 to 48 years in response to national and international regulatory actions. Specific origins of atmospheric trace elements were from the copper refining industry, refuse incineration, coal combustion, vehicle emissions, oil/coal-fired power plants, and crustal/soil dust. Potential source region analysis indicates dominant sources south of the sampling sites in the US, associated with a higher population and more industrial and transportation activities. The possibility of non-cancer health effects due to inhalation were mostly within acceptable levels. However, potential cancer risk posed by inhalation of some elements cannot be ignored, with values approaching or higher than the acceptable level. Considering that the sampling locations are remote and regionally-representative, our finding emphasizes the importance of continued monitoring of metals in air to assess the effectiveness of control strategies.

Speciation and accumulation pattern of heavy metals from soil to rice at different growth stages in farmland of southwestern China

Paddy rice, one of the most important food crops in Southeast Asia, is considered a main source of human exposure to heavy metal contamination because it efficiently accumulates heavy metals. In the present study, of Japonica rice grains, straw, roots, leaves, and husks and rhizosphere paddy soils (0-20 cm and 20-40 cm depth) were collected from Zunyi in northern Guizhou Province, China. The forms of heavy metals, including Cr, Cd, Pb, Cu, and Zn, in the two soil profiles were investigated using Tessier's five-stage sequential extraction procedure. There was no heavy metal pollution in the study area based on the evaluation of the geo-accumulation index and the potential ecological risk index. Accumulation varied from one area to another, and the highest metal accumulation was found in the order of root > stems > leaves. The bioaccumulation factor (BCF) results revealed that during the grain-filling stage, the rice had high BCF values (> 1) for Cd and Zn. The target hazard quotient (THQ) of ingestion peaked for Cd and reached its minimum level for Zn in not only in adults but also in children. The THQ was ranked as Cd > Cu > Pb > Cr > Zn for both adults and children. The hazard index values for adults and children for the five heavy metals were 1.81 × 10^-3 and 1.55 × 10^-3, respectively, indicating that these metals have little effect on the human body. The lifetime carcinogenic risk values for local adults and children were 4.28 × 10^-5 and 5.92 × 10^-5, respectively, both of which were within the tolerable to acceptable risk range. In summary, obvious hazards for local adults and children were not observed in this study. Considering the total amount and chemical forms of Cd, it is necessary to notify the appropriate departments about the possible rice contamination caused by Cd in the soil.

Contamination identification, source apportionment and health risk assessment of trace elements at different fractions of atmospheric particles at iron and steelmaking areas in China

China has the largest share of global iron and steel production, which is considered to play a significant contribution to air pollution. This study aims to investigate trace element contamination at different fractions of particulate matter (PM) at industrial areas in China. Three PM fractions, PM2.1-9.0, PM1.1-2.1 and PM1.1, were collected from areas surrounding iron and steelmaking plants at Kunming, Wuhan, Nanjing and Ningbo in China. Multiple trace elements and their bioavailability, as well as Pb isotopic compositions, were analysed for identification of contaminants, health risk assessment and source apportionment. Results showed that PM particles in the sites near industrial areas were associated with a range of toxic trace elements, specifically As, Cr(VI), Cd and Mn, and posed significant health risks to humans. The isotopic Pb compositions identified that coal and high temperature metallurgical processes in the steelmaking process were the dominant contributors to local air pollution in these sites. In addition to iron and steelmaking activities, traffic emissions and remote pollution also played a contributing role in PM contamination, confirmed by the differences of Pb isotopic compositions at each PM fraction and statistical results from Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) and Geometrical Analysis for Interactive Aid (GAIA). The results presented in this study provide a comprehensive understanding of PM emissions at iron and steelmaking areas, which helps to guide subsequent updates of air pollution control guidelines to efficiently minimise environmental footprint and ensure long term sustainability of the industries.

Public health implications of particulate matter inside bus terminals in Sao Paulo, Brazil

Good quality ambient air is recognised as an important factor of social justice. In addition, providing access to high-capacity public transportation in big cities is known to be a good practice of social equity, as well as economic and environmental sustainability. However, the health risks associated with air pollution are not distributed equally across cities; the most vulnerable people are more exposed to ambient air as they commute to work and wait for buses or trains at the stations. The overall goal of this work was to assess the determinants of human exposure to particulate matter (PM) during commuting time spent inside bus terminals in the Metropolitan Area of Sao Paulo (MASP), in Brazil. Fine and coarse particles were collected at four bus terminals in the MASP. The concentrations of PM and its harmful constituents (black carbon and metals) were used in order to estimate potential doses and the associated health risk during the time spent at bus terminals in the MASP. Our findings show that bus commuters travelling through the bus terminal in the MASP on weekdays inhaled up to 94% higher doses of PM₁₀ than did those travelling outside the terminal; even on weekends, that difference was as high as 88%. Our risk assessment indicated that time spent inside a bus terminal can result in an intolerable health risk for commuters, mainly because of the Cr present in fine particles. Although bus commuters are exposed to fine particle concentrations up to 2 times lower than the worldwide average, we can affirm that inhalable particles in the MASP bus terminals pose a high carcinogenic risk to the daily users of those terminals, mainly those in the most susceptible groups, which include people with heart or lung disease, older adults and children.

Responses of Eucalyptus globulus and Ficus nitida to different potential of heavy metal air pollution

The present study aimed to explore the tolerance potential of Cd, Pb and Cu and physiological alterations in two common tree species growing in Minia governorate (Egypt) namely: Eucalyptus globulus and Ficus nitida and to investigate the leaf features [leaf area (LA) and specific leaf area (SLA)] associated with the phytoremediation process. The findings may be useful for future surveillance as preliminary reference values for levels of heavy metals in urban and industrial settings. The levels of cadmium, lead and Cupper in plant leaf were determined. The results showed that heavy metals could inhibit the growth of plants including LA and SLA. The water content (WC) and photosynthetic pigments of Eucalyptus and Ficus decreased with the increased concentration of metals. Contrary to chlorophylls (a) and (b), carotenoids and chlorophyll ratio (a/b) showed a significant increase with increasing metals concentration especially that of Cd and Cu. Proline content was relatively increased and soluble carbohydrate content decreased in plants with high metal accumulation. Eucalyptus showed better tolerance capacity for Cd, Pb and Cu when compared to Ficus. The ability of Eucalyptus to accumulate and tolerate metal stress makes this species a good candidate to recuperate heavy metals-contaminated conditions.

The Identification and Use Efficiency Evaluation of Urban Industrial Land Based on Multi-Source Data

Urban industrial land (UIL), which is classified for industrial purposes, is an indispensable component of urban land. Obtaining up-to-date and timely UIL details from the industrial development perspective has practical significance for UIL planning. Therefore, we propose a practical method for integrating UIL identification and use efficiency evaluation at the parcel scale based on multi-source data. The Open Street Map (OSM) data were utilized to generate parcels, which served as basic analytical units. Point of Interest (POI) data combined with a Continuous Bag-of-Words (CBoW)-based Word2Vec model was utilized to acquire UIL information. The entropy-weight Technique for Order Preference by Similarity to Ideal Solution method, combined with economic and environmental UIL indicators obtained from remote sensing images, ground observation data, and statistical data, was used to evaluate UIL use efficiency, and the spatial distribution and utilization degree of UIL within Beijing’s fifth ring road was analyzed. The region within Beijing’s fifth ring road was classified into commercial land, industrial land, and other types, with an overall accuracy of 92.24%. With this method, we found that the distribution of UIL presented a ring structure developing outwards along the ring roads and contained concentrated commercial areas. UIL utilization exhibited a south–north differentiation, and industrial land had lower use efficiency. Our work fully utilized the available fine-scale multi-source data.

Influence of Meteorological Variables and Forest Fires Events on Air Quality in an Urban Area (Córdoba, Argentina)

Extreme environmental events, such as forest fires, are a major emission source of aerosols into the atmosphere. Thus, to investigate the contribution of local forest fires to urban particulate matter, we selected several forest fire indicators, such as number of heat sources, fire events, and burnt area, and collected particles smaller than 2.5 µm (PM_2.5) during a 2.5-year period in Cordoba City (Argentina). Temporal variation of PM_2.5 concentration and composition was described considering fire and nonfire periods, and the influence of meteorological variables was estimated as well. On average, PM_2.5 levels registered in Córdoba city during the study period were lower than values reported for other similar cities in Latin America, despite the fact that during wintertime an increase in PM_2.5 levels was observed due to the occurrence of thermal inversions. Several fire events taking place in the nearby hills around the city during winter and spring 2013 suggest that biomass burning was a strong contribution to urban particles levels, which is consistent with the significant correlation between PM_2.5 concentration and heat sources number. During fire periods, levels of Fe, Ca, and K, were significantly higher than in the nonfire periods, suggesting that these elements can be reliable forest fire markers.

Lichens and Bromeliads as Bioindicators of Heavy Metal Deposition in Ecuador

We evaluated heavy metal deposition in Parmotrema arnoldii and Tillandsia usneoides in response to air pollution in Loja city, Ecuador. We assessed heavy metal (cadmium, copper, manganese, lead and zinc) content in these organisms at nine study sites inside Loja city and three control sites in nearby forests. Concentrations of all studied heavy metals (i.e., cadmium (Cd), copper (Cu), lead (Pb), manganese (Mn) and zinc (Zn)) were highest in downtown Loja. Our study confirms that passive monitoring using lichens and/or bromeliads can be an efficient tool to evaluate heavy metal deposition related to urbanization (e.g., vehicle emissions). We recommend these organisms to be used in cost-effective monitoring of air pollution in tropical countries.

Particle deposition in the human lung: Health implications of particulate matter from different sources

Although ambient particulate matter or particles have been found to be associated with morbidity and mortality all over the world, specific health effects of particles from different sources need further elucidation. The objective of this work is to predict the deposition of particles from different sources in the human lung. The whole lung, consisting of 24 generations of branches from trachea to alveoli, was approximated using a one-dimensional lumped "trumpet" model with a variable cross-sectional area. The aerosol dynamics equation was numerically solved using a finite difference method to investigate the transport and deposition of particles in the lung model. Particles from various sources were assumed to be different in both size and density. We found that in general, coarse particles (> 2.5 µm) were mainly deposited in the tracheobronchial (TB) region by impaction, and fine particles (< 2.5 µm) were mainly deposited in the pulmonary (P) region by sedimentation and diffusion. However, the coarse particles with low density can be deposited in P region by sedimentation. As a comparison, our results found that soil particles, which are coarse with low density, were deposited in the deep lung more than traffic particles, which are fine with high density. Modeling of particle deposition in the human lung indicated that coarse particles generated by crustal sources may have adverse health effects as strong as those resulting from fine particles generated from combustion sources.

Accumulation, temporal variation, source apportionment and risk assessment of heavy metals in agricultural soils from the middle reaches of Fenhe River basin, North China

The Fenhe River basin is the main agricultural and industrial developed area in Shanxi province, China. In recent years, agricultural non-point source pollution in the Fenhe River basin intensified, threatening soil quality and safety in the area. Accumulation of eight heavy metals (HMs) including chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) has been detected in soil samples from 50 agricultural sites (0–20 cm) from the middle reaches of the Fenhe River basin. The ecological and human health risk and potential sources of the eight HMs were investigated. In addition, the human health and ecological risks imposed by the possible sources of the eight HMs were quantitatively apportioned. The enrichment factor (EF) values of Cr, Ni, Cu, Pb and Zn were lower than 2, indicating minimal enrichment, while values for As, Cd and Hg were between 2 and 5, exhibiting moderate enrichment. Temporal variation analysis suggested that most HMs in the study area exhibited low concentrations after 2015, except As. The potential ecological risk index was 174.09, indicating low ecological risk. The total hazard index and cancer risk values were 0.395 and 5.35 × 10⁻⁴ for adults and 2.75 and 3.63 × 10⁻⁴ for children, indicating the accepted standard levels were exceeded for non-carcinogenic risk for children and carcinogenic risks for both adults and children. Four potential sources were identified: (1) natural sources, (2) farming activities, (3) coal combustion, and (4) exhaust emissions. Natural sources represented the largest contributor to ecological risk, accounting for 57.42% of the total. Coal combustion was the major contributor to human health risks, accounting for 43.27% and 43.73% of the total non-carcinogenic risk and carcinogenic risk for adults, respectively, and 42.72% and 43.88% for children, respectively.

The Fenhe River basin is the main agricultural and industrial developed area in Shanxi province, China.