Metals In Particulate Matter Research Articles

Neuroinflammation and Brain Health Risks in Veterans Exposed to Burn Pit Toxins.

Military burn pits, used for waste disposal in combat zones, involve the open-air burning of waste materials, including plastics, metals, chemicals, and medical waste. The pits release a complex mixture of occupational toxic substances, including particulate matter (PM), volatile organic compounds (VOCs), heavy metals, dioxins, and polycyclic aromatic hydrocarbons (PAHs). Air pollution significantly impacts brain health through mechanisms involving neuroinflammation. Pollutants penetrate the respiratory system, enter the bloodstream, and cross the blood-brain barrier (BBB), triggering inflammatory responses in the central nervous system (CNS). Chronic environmental exposures result in sustained inflammation, oxidative stress, and neuronal damage, contributing to neurodegenerative diseases and cognitive impairment. Veterans exposed to burn pit toxins are particularly at risk, reporting higher rates of respiratory issues, neurological conditions, cognitive impairments, and mental health disorders. Studies demonstrate that Veterans exposed to these toxins have higher rates of neuroinflammatory markers, accelerated cognitive decline, and increased risks of neurodegenerative diseases. This narrative review synthesizes the research linking airborne pollutants such as PM, VOCs, and heavy metals to neuroinflammatory processes and cognitive effects. There is a need for targeted interventions to mitigate the harmful and escalating effects of environmental air pollution exposures on the CNS, improving public health outcomes for vulnerable populations, especially for Veterans exposed to military burn pit toxins.

Emission characterizations and environmental impacts of off-road vehicles

This study measured particulate matter (PM) and gaseous pollutants in the exhaust of off-road vehicles (excavators, bulldozers) during idling and working. The fingerprint of metals in PM and the emission factors of off-road vehicles were investigated. The concentrations of total PM (TPM), PM10, and PM2.5 were 14–251, 12–181, and 10–163 mg m−3, respectively, for two kinds of off-road vehicles. PM10 occupied 60–70% of TPM, while PM2.5 accounted for 80–90%of PM10. The calculated emission factors were 0.64–0.94, 0.53–0.79, and 0.32–0.49 g BHP−1 h−1 for TPM, PM10, and PM2.5, respectively. Metallic elements of PM were analyzed in order to evaluate the carcinogenic and non-carcinogenic risks. The results showed that the emission of total metallic elements from the excavator and two bulldozers are 2.7 and 7.9–22.6 mg m−3, respectively, and the dominant components are Zn, Fe, and Al. The total carcinogenic risk of Cd and Pb decreased from 9.4 × 10−8 to 1.3 × 10−8 with increasing the distance from 0 to 150 m away from the three off-road vehicles (one excavator, and two bulldozers). The non-carcinogenic risk of both Cd and Pb is lower than the limits (hazard index = 1), which is considered acceptable.

Assessment of seasonal variations in particulate matter accumulation and elemental composition in urban tree species

Outdoor air pollution in urban areas, especially particulate matter (PM), is harmful to human health. Urban trees and shrubs provide crucial ecosystem services such as air pollution mitigation by acting as natural filters. However, urban greenery comprises a particular biodiversity, and different plant species vary in their capacity to accumulate PM. Twenty-two plant species were analyzed and selected according to their leaf traits, the different fractions of PM accumulated on the leaves (large - PML, coarse - PMC, and fine - PMF) and their chemical composition. The study was conducted in four city zones: urban traffic (UT), urban background (UB), industrial (IND), and rural (RUR), comparing winter (W) and summer (S) seasons. The average PM levels in the air and accumulated on the leaves were higher in W than in S season. During both seasons, the highest PM accumulated on the leaves was recorded at the UT zone. Nine species were selected as the most suitable for accumulating PML, seven as the most efficient for accumulating PMC, and six for accumulating PMF. The leaf area and leaf roundness were correlated negatively with PM accumulation. The evergreen species L. nobilis was indicated as suitable for dealing with air pollution based on PM10 and PM2.5 values recorded in the air. Regarding the PM element and metal composition, L. nobilis, Photinia x fraseri, Olea europaea, Quercus ilex and Nerium oleander were selected as species with notable elements and metal accumulation. In summary, the study identified species with higher PM accumulation capacity and assessed the seasonal PM accumulation patterns in different city zones, providing insights into the species interactions with PM and their potential for monitoring and coping with air pollution.

Metal and oxidative potential exposure through particle inhalation and oxidative stress biomarkers: a 2-week pilot prospective study among Parisian subway workers

ObjectiveIn this pilot study on subway workers, we explored the relationships between particle exposure and oxidative stress biomarkers in exhaled breath condensate (EBC) and urine to identify the most relevant biomarkers for a large-scale study in this field.MethodsWe constructed a comprehensive occupational exposure assessment among subway workers in three distinct jobs over 10 working days, measuring daily concentrations of particulate matter (PM), their metal content and oxidative potential (OP). Individual pre- and post-shift EBC and urine samples were collected daily. Three oxidative stress biomarkers were measured in these matrices: malondialdehyde (MDA), 8-hydroxy-2′deoxyguanosine (8-OHdG) and 8-isoprostane. The association between each effect biomarker and exposure variables was estimated by multivariable multilevel mixed-effect models with and without lag times.ResultsThe OP was positively associated with Fe and Mn, but not associated with any effect biomarkers. Concentration changes of effect biomarkers in EBC and urine were associated with transition metals in PM (Cu and Zn) and furthermore with specific metals in EBC (Ba, Co, Cr and Mn) and in urine (Ba, Cu, Co, Mo, Ni, Ti and Zn). The direction of these associations was both metal- and time-dependent. Associations between Cu or Zn and MDAEBC generally reached statistical significance after a delayed time of 12 or 24 h after exposure. Changes in metal concentrations in EBC and urine were associated with MDA and 8-OHdG concentrations the same day.ConclusionAssociations between MDA in both EBC and urine gave opposite response for subway particles containing Zn versus Cu. This diverting Zn and Cu pattern was also observed for 8-OHdG and urinary concentrations of these two metals. Overall, MDA and 8-OHdG responses were sensitive for same-day metal exposures in both matrices. We recommend MDA and 8-OHdG in large field studies to account for oxidative stress originating from metals in inhaled particulate matter.

Association between exposure to heavy metals in atmospheric particulate matter and sleep quality: A nationwide data linkage study

BackgroundRecent studies have demonstrated that long-term exposure to particulate matter (PM) is associated with poor sleep quality. However, no studies have linked PM constituents, particularly heavy metals, to sleep quality. ObjectiveThis study investigated the association between exposure to heavy metals in PM and sleep quality. MethodsWe obtained nationwide data from the Korean Community Health Survey conducted in 2018 among adults aged 19–80 years. Sleep quality was evaluated using Pittsburgh Sleep Quality Index (PSQI). Poor sleep quality was defined as PSQI ≥5. One-year and three-month average concentrations of heavy metals (lead, manganese, cadmium, and aluminum) in PM with diameter ≤10 μm were obtained from nationwide air quality monitoring data and linked to the survey data based on individual district-level residential addresses. Logistic regression analyses were performed after adjusting for age, gender, education level, marital status, smoking status, alcohol consumption, history of hypertension, and history of diabetes mellitus. ResultsOf 32,050 participants, 17,082 (53.3%) reported poor sleep quality. Increases in log-transformed one-year average lead (odds ratio, 1.14; 95% confidence interval, 1.08−1.20), manganese (1.31; 1.25−1.37), cadmium (1.03; 1.00−1.05), and aluminum concentrations (1.17; 1.10−1.25) were associated with poor sleep quality. Increases in log-transformed three-month average manganese (odds ratio, 1.13; 95% confidence interval, 1.09−1.17) and aluminum concentrations (1.28; 1.21−1.35) were associated with poor sleep quality. ConclusionWe showed for the first time that exposure to airborne lead, manganese, cadmium, and aluminum were associated with poor sleep quality. This study may be limited by self-reported sleep quality and district-level exposure data.

Another one bites the dust – Two street canyons studied with magnetic biomonitoring and OSPM modelling

Urban areas form a mosaic of microenvironments and structures, such as street canyons that are susceptible to elevated levels of traffic related pollutants. Street canyons are a relevant topic in air quality research and modelling since they are prone to reduced natural ventilation and when exposed to increased traffic emissions, can pose a serious risk to public health. We applied magnetic biomonitoring using moss bags to evaluate the quality of Operational Street Pollution Model (OSPM) and to study vertical distribution of modelled particulate matter (PM), magnetic PM and heavy metal pollution in a street canyon in Turku and Helsinki, Finland. Moss bags were attached on opposite sides of the streets at 3-, 6-, 9- and 12-m heights for 44 days in late autumn. Samples were analysed for mass-specific magnetic susceptibility (χ), hysteresis parameters and elemental components. High χ values and elemental concentrations of Fe, Al, Ti, Zn, Mn, Cu and Ba were found in both street canyons. Compared to measurements with airborne magnetic PM, the OSPM model underestimated the difference in PM concentrations between the opposite street canyon faces and overestimated the dilution of PM concentrations with altitude. In Turku the results between the OSPM model and magnetic measurements were incompatible. We suspect this is due to meteorological model input data from a distant weather station, street canyon features and a high slope angle contributing to non-uniform emissions in the street canyon. We demonstrate that the moss bag technique is a versatile tool to understand the small-scale variations of concentrations in a variety of complex urban environments.

Migration and emission characteristics of metal pollutants in fluid catalytic cracking (FCC) process

Fluid catalytic cracking (FCC) is the core unit for heavy oil conversion in refineries. In the FCC process, the metal contaminants from the feedstock are deposited on the catalysts, causing catalyst deactivation and metal particulate matter (PM) emission. However, the migration and emission characteristics of metal pollutants in FCC units are still unclear. Here, the stack tests of three FCC units were carried out to monitor metal PM emissions, and the metal contents of the feedstock oil and spent catalyst were detected. For the metal migration from the feedstock to the catalysts, Ni, Fe, and V have high concentrations and migration rates while other metals perform much lower. The metal distribution on the spent catalysts profoundly determines the metal mobility to the flue gas and the regeneration process affects the catalyst attrition, leading to metal PM emissions discrepancy. The migration rate and emission concentration of V in the deeper layers of the catalysts are much lower than those of Ni at the particle’s exterior. Finally, the stack data was used to calculate the emission factors and ratio factors of the metal PM. This work is expected to advance metal migration cognition and metal pollutants emissions estimation in FCC units.

Evaluation of Toxic Heavy Metals and Health Risk in Airborne Particulate Matter at Qassim region, Saudi Arabia

Particulate matter (PM) significantly influences air quality, visibility, climate change, the earth’s radiative balance, and human health. The significance of carrying out this investigation in its entirety is due to the small amount of data that has been collected and published in Qassim region (26.2078º N, 43.4837º E). Understanding the origins of PM and its chemical species in Qassim districts is advantageous for the purpose of identifying impacts on one’s health Characterization of pollution sources also will assist in the success of mitigation strategies and solve the issue of increased PM concentrations in outdoor areas. Therefore, this study described the physical and chemical properties of PM by measuring the PM1, PM2.5, and PM10 concentrations in Qassim’s central urban and rural areas. In urban Qassim, the average PM1, PM2.5, and PM10 concentrations were 12.23, 33.16, and 155.38 µg/m3, respectively. On the other hand, the average PM1, PM2.5, and PM10 concentrations reached 8.18, 23.03, and 93.57 µg/m3 in rural Qassim, respectively. The findings revealed that fine particle concentrations have risen over allowable levels due to dust storms. A total of 18 elements and 8 chemical compounds were determined and identified. The compound concentrations of Al2O3, SiO2, CaO, TiO2, K2O, BaO, MnO, Fe2O3 and the essential elements Sr, V, Al, Cu, Ca, Fe, Cr, As, Zr, K, Br, Ba, Pb, Mn, Ni, Zn, Rb and Ti were determined using XRF and XRD. The findings revealed that fine particle concentrations have risen over allowable levels due to dust storms. The main elements in the trace elements were Ca, Fe, Al, Sr, K, and Mg, indicating significant contributions from the soil (Ca, Fe, Al, Mg), as well as from industrial and vehicle emissions (Sr, Ca, Al, Fe, K). V, Cu, Zn, Cr, Ni, Pb, Sr, As, Mn and Br fall under the anthropogenic category of trace elements, while Al, S, Na, Mg, Rb, K, Zr, Ti, Fe, Mn, Sr, Y, Cr, Ca, Ni, Zn and Cu are obtained from the earth's crust. HIGHLIGHTS The study measured levels of toxic heavy metals in airborne particulate matter (PM) in the Qassim region of Saudi Arabia The results indicated that the concentrations PM were higher than the recommended guidelines set by the World Health Organization (WHO), which poses a potential health risk to the population The study suggests that the major sources of heavy metals in the Qassim region are from dust storms and anthropogenic activities such as industrial activities and traffic emissions The study highlights the importance of regular monitoring of heavy metals in PM and the need for effective pollution control measures to protect public health GRAPHICAL ABSTRACT

Prenatal and postnatal exposure to heavy metals in PM2.5 and autism spectrum disorder

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders, and its incidence is increasing over time. Although several environmental factors have been suspected to be risk factors for ASD, studies on the effects of airborne heavy metals on newly developed ASD are still limited. We conducted a large birth cohort study of 168,062 live term births in Taichung during 2004–2011 to assess the association of heavy metals in particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) with ASD, and identify sensitive time windows during prenatal and postnatal periods. Heavy metals, including arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in PM2.5, were estimated using the Weather Research and Forecasting/Chem (WRF/Chem), inserted from the top 75 emission sources for the module. The association between childhood ASD and 4 metals were analyzed from pregnancy to 9 months after birth. The Cox proportional hazard model with a distributed lag nonlinear model (DLNM) was used to estimate the association between heavy metals in PM2.5 and ASD. We identified 666 incident ASD cases in 168,062 participants. A positive association between Hg and ASD was found at 9 months after birth (Hazard Ratio: 1.63; 95% CI: 1.13–2.36). According to the DLNM, there was an increased risk of exposure to Hg during 10–25 weeks after birth, and decreased risk of exposure to Hg during gestational weeks 4–6. Exposure to As and Hg on the risk of ASD were significantly stronger in low birth weight infants (<2500 g) than in those of birth weight ≥2500 g during postnatal period. Postnatal exposure to Hg in PM2.5 may associate with increased ASD incidence. Infants with low birth weight and exposure to As and Hg in PM2.5 are more likely to develop ASD.

Size-segregated source identification of water-soluble and water-insoluble metals and trace elements of coarse and fine PM in central Los Angeles

In this study, the water-solubility and sources of metals and trace elements in both fine and coarse particulate matter (PM) were investigated in Central Los Angeles. Sampling was performed in the winter, spring, and summer of 2022 at the Particle Instrumentation Unit (PIU) of the University of Southern California located in the proximity of I-110 freeway. Both fine and coarse PM samples were collected using Personal Cascade Impactors (PCIS) and chemically analyzed to determine their water-soluble and water-insoluble metal content. Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) were used to determine the sources of soluble and insoluble metals and obtain their contributions to total metal concentration. Our results indicate that the water-solubility of most of the metals is higher in the fine size fraction compared to the coarse fraction. Seasonal variations in the water solubility of selected metals for both coarse and fine fractions were observed, with higher water-soluble metal concentrations in summer for several species (e.g., Fe, S, Pb, Cu, La, Ni, and Al), possibly due to higher photochemical processing, while in winter, almost all species exhibited higher insoluble fraction concentrations. The PCA and MLR analyses results showed that tire and brake wear was the most significant contributor to the total metals for both fine soluble and insoluble portions, accounting for 35% and 75% of the total metals, respectively. Combustion sources also contributed substantially to water-soluble metals for fine and coarse size ranges, representing 40% and 32% of the total metal mass, respectively. In addition, mineral dust and soil and re-suspended dust were identified as the highest contributors to coarse metals. The MLR analysis also revealed that secondary aerosols contributed 11% to the fine water-soluble metals. Our results suggest that non-tailpipe emissions significantly contribute to both coarse and fine PM metals in the Central Los Angeles region.

Analysis of metals in particulate matter suspended in air by total reflection x‐ray fluorescence

AbstractAtmospheric particulate matter (PM) is considered to be a set of pollutants suspended in the air, from industrial processes, motor vehicle exhaust, resuspended street dust, biomass burning, and others. Among the toxic chemical compounds, PM is considered contaminants of great importance for researchers, as they offer harmful effects to humans, fauna and flora. Moreover, exposure to PM can cause the development and/or worsening of diseases, mainly respiratory and cardiovascular. The aim of the present study was to evaluate the metals concentration in total suspended particulate matter in the air through total reflection x‐ray fluorescence technique (TXRF). The samples were collected from random points in five neighborhoods in the Metropolitan Region of the state of Rio de Janeiro/Brazil. TXRF measurements were performed using the benchtop TXRF spectrometer S2 PICOFOX. The results showed that the proposed methodology was able to detect the elements Cr, Fe, Ni, Cu, and Zn, in concentrations ranging from 2.0 to 200 ng.m−3. It can be concluded that the study methodology for determining the metal concentrations in air samples is an efficient and low‐cost solution for studying environmental pollution.

In Vitro Bioaccessibility and Health Risk of Heavy Metals from PM2.5/PM10 in Arid Areas—Hotan City, China

The impact of heavy metals in particulates plays an assignable role in human health—especially in the northwest region of China, which is affected by severe dust storms—and the bioaccessibility and health risks of heavy metals in particulate matter have not yet been quantified and evaluated. This study used Gamble’s solution and PBET (physiologically based extraction test) experiments to simulate the human respiratory and digestive systems, and analyzed the concentrations and bioaccessibility of Pb, Mn, Ni, Cd and As in PM2.5 and PM10 samples in the urban area of Hotan City during summer (July) and winter (January). The result shows that Mn and Pb are the most abundant elements in five metals. The bioaccessibility of Mn in gastric fluid was the highest in both summer (PM2.5: 64.1%, PM10: 52.0%) and winter (PM2.5: 88.0%, PM10: 85.1%). Meanwhile, in the respiratory system, the highest bioaccessibility of PM2.5 and PM10 in summer was Ni (53.3%), and Pb (47.9%), respectively. Although the concentration of Cd is low in winter, its bioaccessibility in lung fluid was the highest (PM2.5: 74.7%, PM10: 62.3%). The USEPA standard model and Monte Carlo simulation results show that the heavy metals in PM2.5 and PM10 would give rise to non-carcinogenic risk for both adults and children through the respiratory system in summer but had little risk in winter. However, the metal may have non-carcinogenic risk to children through intake. In addition, there is a cancer risk to adults through the respiratory system in winter (PM2.5: CR = 1.80 × 10−6, PM10: CR = 2.82 × 10−6), while there is a carcinogenic risk through the digestive system regardless of season and age.

Risk Assessment of the Impact of Heavy Metals in Urban Traffic Dust on Human Health

Excessive exposure to heavy metals induces potential adverse health impacts in humans. More specifically, heavy metals in particulate matter (PM) have a significant impact since PM can penetrate human organs and systems, causing several morbidities. In this work, dust samples were collected from 20 different types of roads in a busy zone in Doha during the winter of 2016–2017, where a higher human exposure rate occurs due to extensive outdoor activities during this time of the year. The elemental composition in terms of the mass concentration of 30 elements was determined in each sample via an energy-dispersive X-ray fluorescence (XRF) spectrometer. Then, the toxicity of six heavy metals in these airborne traffic dust samples was investigated. The heavy metals reported to have a hazardous impact on human health are As, Pb, Hg, Cd, Cr, Co, Ni, Cu, and Zn. The extent of carcinogenic and non-carcinogenic risk impact was assessed using pollution indices and then determining the health risks associated with exposure to heavy metals through inhalation, ingestion, and dermal contact. The non-carcinogenic hazard index analysis results indicate no toxicity for all metals. However, the carcinogenic risk factor results show that only chromium might induce a slight risk for children and adults. In light of this, further research is recommended to investigate more areas in urban Doha where more samples can be collected and analyzed.

Measurement artifacts in the dithiothreitol (DTT) oxidative potential assay caused by interactions between aqueous metals and phosphate buffer

Metals in particulate matter (PM) are hypothesized to have enhanced toxicity based on their ability to catalyze reactive oxygen species (ROS) formation. Acellular assays are used to measure the oxidative potential (OP) of PM and its individual components. Many OP assays, including the dithiothreitol (DTT) assay, use a phosphate buffer matrix to simulate biological conditions (pH 7.4 and 37 °C). Prior work from our group observed transition metal precipitation in the DTT assay, consistent with thermodynamic equilibria. In this study, we characterized the effects of metal precipitation on OP measured by the DTT assay. Metal precipitation was affected by aqueous metal concentrations, ionic strength, and phosphate concentrations in ambient PM sampled in Baltimore, MD and a standard PM sample (NIST SRM-1648a, Urban Particulate Matter). Critically, differences in metal precipitation induced differing OP responses of the DTT assay as a function of phosphate concentration in all PM samples analyzed. These results indicate that comparison of DTT assay results obtained at differing phosphate buffer concentrations is highly problematic. Further, these results have implications for other chemical and biological assays that use phosphate buffer for pH control and their use to infer PM toxicity.

Particulate Matter Accumulation and Elemental Composition of Eight Roadside Plant Species

Particulate matter (PM) is the most dangerous air pollutant that adversely affects health. Increasing PM in urban areas is a big problem that must be solved. This study analyzed the amount of PM that accumulated on plant leaves, as well as the leaf traits that contribute to PM accumulation, to determine the plant’s ability to accumulate PM and the impact of PM on the plants. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis were used to quantitatively assess metal concentrations in the particles that had accumulated on the leaf samples. Eight common plant species that grow on the roadside were used to analyze leaf traits using leaf samples. Specific leaf areas (SLA), leaf extract pH (pH), relative leaf water content (RWC), chlorophyll (Chl), and carotenoids were analyzed. PM accumulation and leaf traits varied among plant species, and Parthenocissus tricuspidata showed the highest PM accumulation on its leaf surface. The leaf’s elemental composition included C, O, Ca, K, Mg, S, P, Al, Si, Na, Cl, and Fe. Among these elements, Ca, K, and Cl made up a relatively large percentage. Fe was only detected in the leaves of Pachysandra terminalis and P. tricuspidata, while C and O were excluded as they are not relevant in determining PM metal content. Plants not only accumulate PM but also heavy metals from the atmosphere. This study found that plants with highly effective PM accumulation, such as P. tricuspidate, should be considered for optimizing the benefits of plants in improving air quality.

Estimation of Heavy Metals Content at Traffic Inter-Change Ita-Marun Epe Lagos State Nigeria

This study assesses the vehicular and traffic emission at Ita-marun Epe Lagos State. Road traffic area contains contaminants which affects human, animals and plants. Hence, the need to investigate the concentrations of these contaminants within the selected area. Three deposition gauges of 0.15 by 0.20 mm were planted at selected sampling site for 30 days between December 2021 and January 2022. The Lagos State University Epe campus was used as the control experiment for this research work. Deposition flux for each site was determined. The contaminants levels of the heavy metals in particulate matter were evaluated using the Enrichment Factor (EF) analysis. Deposition fluxes determined range from 31.8269-39.7836 g/m2/month at the sampling site while it ranges 42.3934-51.0567 g/m2/month at control site. Elemental analyses of all the samples collected were determined using the Energy Dispersive X-ray Fluorescence (EDXRF). EF reveals that 7 elements Ag, Cd, Cr, In, Mn, Sn, and Zn are highly enriched at sampling site while 6 elements S, Cl, Zn, Ge, As and W at the control site respectively. Results shows that fluxes at the control site were higher than that of the sampling site. EF also reveals that seven elements at the sampling site and six elements at the control site were anthropogenically derived. Due to the findings of this research, a clean-up of this area is highly recommended.

On the nature of heavy metals in particulate matter (PM10, PM2.5) and their health impact assessment for a desert city in Iran, Birjand

&#x0D; &#x0D; &#x0D; &#x0D; Introduction: Air pollution is the leading environmental risk factor for health. This study aimed to assess heavy metals in Particulate Matter (PM10 , PM2.5) and their health impact assessment for a desert city in Iran, Birjand.&#x0D; Materials and methods: In this study, the concentrations of PM10 and PM2.5 were measured from September 2019 to March 2020. Measurements were performed once every six days for 24 h using high-volume samplers. Moreover, health-related effects attributed to the suspended particles were estimated using the AirQ2.2.3.&#x0D; Results: Mean and standard deviation of PM10 and PM2.5 concentrations were 97.5±38.7 μg/m3 and 36.3±19.1 μg/m3, respectively. The mean metal concentrations in PM2.5 were in the Co&gt;Cd&gt;Ce&gt;V order, while the metal concentrations in PM10 were in the Cd&gt;As&gt;Ce&gt;V order. The lowest and highest number of deaths attributed to PM2.5 per 100,000 persons were related to ischemic heart disease (1.73) and chronic respiratory disease (18.35). The highest number of deaths attributed to PM10 per 100,000 persons was related to chronic bronchitis in adults (35.74).&#x0D; Conclusion: This study revealed that particle-based air pollution negatively affects health as caused by heavy metals, whereas further research is required to determine the effects of bacterial and fungal bioaerosols on human health. Monitoring the elemental composition of atmospheric particles can contribute to better air quality management.&#x0D; &#x0D; &#x0D; &#x0D;

Characteristics and health risk assessment of heavy metal pollution in atmospheric particulate matter in different regions of the Yellow River Delta in China.

To understand the characteristics, temporal and spatial variation, and health risks of atmospheric heavy metal pollution in different areas of the YRD (Yellow River Delta), atmospheric particles samples were collected in the YRD in China during 2016-2017. A total of 10 monitoring points were chosen in different areas (industrial parks, main urban areas, and rural areas) in the YRD, heavy metals were monitored using atomic fluorescence spectrometry and graphite furnace atomic absorption spectrometry. The results showed that TSP (total suspended particulate), PM10 (particulate matter with an aerodynamic diameter less than 10μm), and PM2.5 (particulate matter with an aerodynamic diameter less than 2.5μm) contents were higher in the Kenli EDZ (economic development zone) and Kenli urban areas than those in other points. The concentration range of heavy metals in atmospheric samples at 10 points was different, with a difference of five orders of magnitude, of which the content of copper (Cu) was the highest, with the highest concentration of 4.375μg/m3, and the content of particulate mercury (Hg) was the lowest, with the minimum concentration of 0.00001μg/m3. Among the nine heavy metals, the contents of cadmium (Cd), lead (Pb), and Hg were higher in winter than in summer, and chromium (Cr), nickel (Ni), Cu, and manganese (Mn) were higher in summer than in winter. In addition to Hg, the contents of the other eight heavy metals in particulate matter showed a trend that urban areas and EDZs had higher concentrations than cities and towns and nature reserves, which can be attributed to industrial activities and coal-fired fuel emissions. Health risk assessment was carried out for adults and children, respectively, and the results showed that carcinogens have no obvious carcinogenic risk, but As and Cr have major potential carcinogenic risk. Among the noncarcinogenic substances, Mn has the greatest noncarcinogenic risk, and urban areas and economic development zones have the greatest risk. This study investigated the characteristics and health risk assessment of atmospheric heavy metal pollution in different areas in the YRD to supplement the research contents of atmospheric particulate heavy metals in the YRD in domestics and overseas. It is also critical to study the pollution and migration of heavy metals in China.

Phyto-cleaning of particulate matter from polluted air by woody plant species in the near-desert city of Jodhpur (India) and the role of heme oxygenase in their response to PM stress conditions.

Particulate matter (PM) is one of the most dangerous pollutants in the air. Urban vegetation, especially trees and shrubs, accumulates PM and reduces its concentration in ambient air. The aim of this study was to examine 10 tree and shrub species common for the Indian city of Jodhpur (Rajasthan) located on the edge of the Thar Desert and determine (1) the accumulation of surface and in-wax PM (both in three different size fractions), (2) the amount of epicuticular waxes on foliage, (3) the concentrations of heavy metals (Cd and Cu) on/in the leaves of the examined species, and (4) the level of heme oxygenase enzyme in leaves that accumulate PM and heavy metals. Among the investigated species, Ficus religiosa L. and Cordia myxa L. accumulated the greatest amount of total PM. F. religiosa is a tall tree with a lush, large crown and leaves with wavy edge, convex veins, and long petioles, while C. myxa have hairy leaves with convex veins. The lowest PM accumulation was recorded for drought-resistant Salvadora persica L. and Azadirachta indica A. Juss., which is probably due to their adaptation to growing conditions. Heavy metals (Cu and Cd) were found in the leaves of almost every examined species. The accumulation of heavy metals (especially Cu) was positively correlated with the amount of PM deposited on the foliage. A new finding of this study indicated a potentially important role of HO in the plants' response to PM-induced stress. The correlation between HO and PM was stronger than that between HO and HMs. The results obtained in this study emphasise the role of plants in cleaning polluted air in conditions where there are very high concentrations of PM.

Atmospheric Concentration of CO2 and PM2.5 at Salina, Stromboli, and Vulcano Islands (Italy): How Anthropogenic Sources, Ordinary Volcanic Activity and Unrests Affect Air Quality.

Geogenic and anthropogenic sources of atmospheric particulate and CO2 can lead to threats to human health in volcanic areas. Although the volcanic CO2 hazard is a topic frequently debated in the related scientific literature, space and time distribution of PM2.5 are poorly known. The results of combined CO2/PM2.5 surveys, carried out at Salina, Stromboli, and Vulcano islands (Aeolian archipelago, Italy) in the years 2020–2021, and integrated with investigations on bioaccumulation of metallic particulate matter by the mean of data on the magnetic properties of oleander leaves, are presented in this work. The retrieved results indicate that no significant anthropogenic sources for both CO2 and PM2.5 are active in these islands, at the net of a minor contribution due to vehicular traffic. Conversely, increments in volcanic activity, as the unrest experienced by Vulcano island since the second half of 2021, pose serious threats to human health, due to the near-ground accumulation of CO2, and the presence of suspended micro-droplets of condensed hydrothermal vapor, fostering the diffusion of atmophile viruses, such as the COVID-19. Gas hazard conditions can be generated, not only by volcanic vents or fumarolic fields, but also by unconventional sources, such as the outgassing from shallow hydrothermal aquifers through drilled or hand-carved wells.