Characteristics, sources and health risk assessment of toxic heavy metals in PM2.5 at a megacity of southwest China

Characteristics and health risks assessment of PM2.5-bound heavy metals during winter in urban areas of northern China: A case study in Kaifeng

The health impact of heavy metals in atmospheric PM2.5 has garnered increasingly widespread attention. We have collected PM2.5 samples in a typical city (Kaifeng) within the Central Plains Urban Agglomeration in China during winter and measured the mass concentration of PM2.5-bound heavy metals. The pollution of As and Cr in the urban atmosphere requires significant attention. As PM2.5 concentrations increased, the enrichment factors (EFs) of Mn, Cu, Zn, As, and Pb also rose, suggesting a growing contribution from anthropogenic emissions. The analysis showed that the hazard quotient (HQ) for the non-heating and heating periods (HQ < 1) did not result in a cumulative non-carcinogenic health risk to humans. Regarding carcinogenic effects, As and Cr exhibit significant carcinogenic impacts on both children and adults (ELCR>1 × 10-6), indicating that the carcinogenic risks posed by As and Cr under PM2.5 exposure in Kaifeng could not be overlooked. It was found that industrial and biomass combustion are the primary sources of carcinogenic risk in Kaifeng city. From the non-heating to the heating period, the industrial carcinogenic risk increased from 37.12 % to 43.39 %, while the contribution of biomass burning remained at 25 %. This result was strongly correlated with the high proportions of heavy metal elements such as As, Mn, Pb, and Ni from the metal refinery industry. The results of this study revealed the equally important source of heavy metals, compared to coal combustion in North China Plain. In addition to residential coal combustion, industrial emissions are a major source of PM2.5-bound heavy metals in Kaifeng, contributing significantly to overall air pollution and providing a useful reference to mitigating human health risks in the area.

Hair Heavy Metals and Food Consumption in Residents of Chengdu: Factors, Food Contribution, and Health Risk Assessment

Heavy metal pollution is one of the most pressing issues threatening food security and human health. This study assesses heavy metal (chromium, cadmium, copper, zinc, nickel, and lead) exposure via hair metal concentrations in Chengdu residents, reflecting metal intake from food consumption. From June 2020 to February 2021, a sampling survey was conducted on residents' hair (n=182) and food (n=301) in six main urban areas of Chengdu. The concentrations of heavy metals in hair and food were analyzed by inductively coupled plasma mass spectrometry, and the results showed that the residents of Chengdu City had high hair concentrations of Cd (0.17±0.03 mg kg-1) and Zn (293±21.3 mg kg-1). Gender significantly affected the hair Cr, Zn, and Ni concentrations. Based on the survey results obtained from Chengdu City residents, the habits and diet structure are assessed for the influence of six heavy metals in the hair of the residents. Adolescents' (13-18 years old) hair had significantly higher Pb concentrations than adults (19-59 years old). The concentration of Ni in hair was affected by perming and dyeing habits. For dietary exposure, cereals and meat were the main contributors to the residents' daily intake of heavy metals. The bioaccessibility of Cr, Cd, Cu, Zn, Ni, and Pb in food was 2.45-74.67%, 10.6-78.7%, 13.4-82.5%, 8.89-89.2%, 7.70-85.1%, and 15.4-86.2%, respectively. In health risk evaluation based on the bioaccessible fraction of six heavy metals, the hazard quotient of each heavy metal in food was less than 1, indicating no potential non-carcinogenic risk.

A Comparison of Health Risks from PM2.5 and Heavy Metal Exposure in Industrial Complexes in Dangjin and Yeosu·Gwangyang

Particulate matter (PM) can cause illness, including respiratory diseases, and PM2.5 compositions are likely to vary according to the emission profiles of industrial complexes. This study analyzed and compared the concentrations and distributions of PM2.5 and heavy metals in two regions of Republic of Korea: Yeosu·Gwangyang, which houses a massive national industrial complex, and Dangjin, which houses power plants. Further, we conducted a health risk assessment on the residents of the areas near these industrial complexes. Measurements were taken at five different points in each setting over a two-year period from August 2020 to August 2022. We found differences in PM2.5 concentrations and heavy metal composition ratios across the sites. Specifically, PM2.5 concentrations exceeded the standard of 1 at all measurement sites, while the specific heavy metals exceeding the standard varied across the sites. Ultimately, we observed regional differences in PM2.5 composition across measurement sites across and within the two regions and variations in health risks and according health effects due to the absence of PM2.5 toxicity values, and compared the health risks of two industrial complexes with different characteristics. These findings underscore the importance of considering not only PM2.5 but also its composition in exposure and health risk assessments.

Investigating PM2.5 toxicity in highly polluted urban and industrial areas in the Middle East: human health risk assessment and spatial distribution

Exposure to particulate matter (PM) can be considered as a factor affecting human health. The aim of this study was to investigate the concentration of PM2.5 and heavy metals and their influence on survival of A549 human lung cells in exposure to PM2.5 breathing air of Ahvaz city. In order to assess the levels of PM2.5 and heavy metals, air samples were collected from 14 sampling stations positioned across Ahvaz city during both winter and summer seasons. The concentration of heavy metals was determined using ICP OES. Next, the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] was employed to ascertain the survival rate of A549 cells. The findings from this research demonstrated that average PM2.5 of the study period was (149.5 μg/m3). Also, the average concentration of PM2.5 in the urban area in winter and summer was (153.3- and 106.9 μg/m3) and in the industrial area this parameter was (191.6 and 158.3 μg/m3). The average concentration of metals (ng/m3) of urban areas against industrial, Al (493 vs. 485), Fe (536 vs. 612), Cu (198 vs. 212), Ni (128 vs. 129), Cr (48.5 vs. 54), Cd (118 vs. 124), Mn (120 vs. 119), As (51 vs. 67), Hg (37 vs. 50), Zn (302 vs. 332) and Pb (266 vs. 351) were obtained. The results of the MTT assay showed that the highest percentage of cell survival according to the exposure concentration was 25 > 50 > 100 > 200. Also, the lowest percentage of survival (58.8%) was observed in the winter season and in industrial areas with a concentration of 200 μg/ml. The carcinogenic risk assessment of heavy metals indicated that except for Cr, whose carcinogenicity was 1.32E-03, other metals were in the safe range (10-4-10-6) for human health. The high concentration of PM2.5 and heavy metals can increase respiratory and cardiovascular diseases and reduce the public health level of Ahvaz citizens.

Trace elements in ambient aerosols and size-resolved fog droplets: Trends, enrichment, and risk assessment

Ambient particulate matter (PM) is composed of inorganic and organic components. The contribution of each component is impacted by various factors such as emission sources, atmospheric aging process, and size of the PM or droplets. This study mainly focuses on the effect of the PM and droplet size on trace elemental concentrations, for which various size fractions of ambient PM (PM₁, PM_2.5) were collected on quartz filters along with fog water (FW) samples during winter. Simultaneous, online measurements of the mass concentrations of PM₁ and PM_2.5 were also carried out. At the time of the collection, the mass concentration of PM_2.5 ranged from 19 to 890 μg/m³, and its mean value was 227 μg/m³. During the sampling period, 17 fog events occurred and caused a 27% reduction in the mean pre-fog PM_2.5 concentration. All the PM and FW samples were analyzed for 12 trace elements: Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Zn, V. The concentrations of the various trace elements in the PM₁, PM_2.5, and FW samples encompassed a wide range: 10 (V)-2432 (Na) ng/m³, 34 (Mn)-13810 (Na) ng/m³, and 8 (Cr)-19870 (Ca) μg/l, respectively. The concentrations of the trace elements in the FW samples indicated a droplet-size-dependent trend: the small droplets (diameter <16 μm) had several times (3-10 times) higher concentrations than the coarser droplets (diameter >22 μm). The enrichment factor (EF) analysis revealed that the EF values for almost all the trace elements were an order of magnitude higher in the FW samples than in PM₁ and PM_2.5. Risk assessment based on toxic elements suggested a very high inhalation carcinogenic risk (231 per million) for the exposed population during foggy periods. This study will facilitate decision-making by policymakers regarding air quality and health concerns.

Pollution levels and health risk assessment of potentially toxic metals of size-segregated particulate matter in rural residential areas of high lung cancer incidence in Fuyuan, China

The highest incidence and mortality rate of lung cancer in rural area of Fuyuan has been a research hotspot, and the pathogenesis is still unclear. Therefore, atmospheric particulate matters (APMs) samples were collected between 18 February and 01 March 2017, exploring water-soluble potentially toxic metals (WSPTMs) and water-soluble inorganic ionic species (WSIIs) levels, size distribution, sources, acidity and alkalinity, and potential carcinogenic and non-carcinogenic risks, hoping to provide scientific basic data to solve this problem. In our study, the average ratio of nitrate ion (NO₃^-)/sulfate ion (SO₄^2-) within PM_1.1, PM_1.1-2.0, PM_2.0-3.3, PM_3.3-7.0, and PM_>7.0 were 0.22, 0.18, 0.15, 0.34 and 0.36, respectively, that revealed that combustion sources contributed to PM were more significant. The anions in equilibrium (ANE) / cations in equilibrium (CAE) < 1 for all samples within PM_1.1, PM_2.0-3.3, PM_3.3-7.0 indicate that the APMs were alkaline, but PM_1.1-2.0 particulate matter shows weak acidity. SO₄^2- prefers to combine with NH₄⁺ to form (NH₄)₂SO₄, which hinders the formation of NH₄NO₃, the remaining SO₄^2- and NO₃^- to neutralize the K⁺, KNO₃ was formed at all particulate, however, K₂SO₄ can only be formed in PM_<3.3. Arsenic (As) and Selenium (Se) were identified as the most enriched WSPTMs in all PM sizes, predominantly from anthropogenic emissions, were suggested that coal combustion is a significant source of PM-bound WSPTMs. Total WSPTMs exhibited high total carcinogenic risks (TCR) values (9.98 × 10^-6, 1.06 × 10^-5, and 1.19 × 10^-5 for girls, boys and adults, respectively) in the smaller particles (< 1.1 μm). Se was considered as the major contributor (63.60%) to carcinogenic risk (CR) in PM_2.0 and had an inverse relationship with PM size that should be of prime concern.

Trends in elemental Pb concentrations within atmospheric PM2.5 and associated risk to human health in major cities of China

High concentrations of elemental lead (Pb) in the atmosphere pose a serious threat to human health. This study presents and summarizes data obtained from relevant literature on Pb concentrations within fine particulate matter (PM_2.5) recorded in major cities in China from 2008 to 2019. An environmental health risk assessment model was then used to evaluate the health hazards of inhaling Pb among adults and children in China. Owing to the promulgation and implementation of a series of air pollution control measures, the Pb concentrations within PM_2.5 measured in major cities in China showed a downward trend after peaking in 2013. The concentrations were higher in winter than in summer, and higher in northern cities than in southern cities. Although the Pb concentrations in most cities did not exceed the limit (500 ng/m³) set by China, they remained much higher than concentrations recorded in developed countries. The results of the environmental health risk analysis showed that the non-carcinogenic risk from atmospheric Pb exposure was higher in children than in adults (adult females > adult males), while the carcinogenic risk was higher in adults than in children. This study shows that even if the health risk of Pb in PM_2.5 does not exceed the acceptable limit, stricter Pb pollution control measures are required to safeguard population health due to the dangers of Pb.

Chemical Composition, Sources, and Health Risk Assessment of PM2.5 and PM10 in Urban Sites of Bangkok, Thailand

Of late, air pollution in Asia has increased, particularly in built-up areas due to rapid industrialization and urbanization. The present study sets out to examine the impact that pollution can have on the health of people living in the inner city of Bangkok, Thailand. Consequently, in 2021, fine particulate matter (PM_2.5) and coarse particulate matter (PM₁₀) chemical composition and sources are evaluated at three locations in Bangkok. To identify the possible sources of such particulates, therefore, the principal component analysis (PCA) technique is duly carried out. As determined via PCA, the major sources of air pollution in Bangkok are local emission sources and sea salt. The most significant local sources of PM_2.5 and PM₁₀ in Bangkok include primary combustion, such as vehicle emissions, coal combustion, biomass burning, secondary aerosol formation, industrial emissions, and dust sources. Except for the hazard quotient (HQ) of Ni and Mn of PM_2.5 for adults, the HQ values of As, Cd, Cr, Mn, and Ni of both PM_2.5 and PM₁₀ were below the safe level (HQ = 1) for adults and children. This indicates that exposure to these metals would have non-carcinogenic health effects. Except for the carcinogenic risk (HI) value of Cr of PM_2.5 and PM₁₀, which can cause cancer in adults, at Bangna and Din Daeng, the HI values of Cd, Ni, As, and Pb of PM_2.5 and PM₁₀ are below the limit set by the U.S. Environmental Protection Agency (U.S. EPA). Ni and Mn pose non-carcinogenic risks, whereas Cr poses carcinogenic risks to adults via inhalation, a serious threat to the residents of Bangkok.

Winter and spring variation in sources, chemical components and toxicological responses of urban air particulate matter samples in Guangzhou, China

The sources and chemical components of urban air particles exhibit seasonal variations that may affect their hazardousness to human health. Our aims were to investigate winter and spring variation in particulate matter (PM) sources, components and toxicological responses of different PM size fractions from samples collected in Guangzhou, China. Four size-segregated PM samples (PM_10-2.5, PM_2.5-1, PM_1-0.2, and PM_0.2) were collected separately during winter (December 2017 and January 2018) and spring (March 2018). All PM samples were analyzed for chemical components and characterized by source. RAW 264.7 macrophages were exposed to four doses of PM samples for 24 h. Cytotoxicity, oxidation, cell cycle, genotoxicity and inflammatory parameters were tested. PM concentrations were higher in the winter samples and caused more severe cytotoxicity and oxidative damage than to PM in the spring samples. PM in winter and spring led to increases in cell cycle and genotoxicity. The trends of size-segregated PM components were consistent in winter and spring samples. Metallic elements and PAHs were found in the largest concentrations in winter PM, but ions were found in the largest concentrations in spring PM. metallic elements, PAHs and ions in size-segregated PM samples were associated with most toxicological endpoints. Soil dust and biomass burning were the main sources of PM in winter, whereas traffic exhaust and biomass burning was the main source with of spring PM. Our results suggest that the composition of PM samples from Guangzhou differed during winter and spring, which led to strong variations in toxicological responses. The results demonstrate the importance of examining a different particle sizes, compositions and sources across different seasons, for human risk assessment.

Spatial distribution and risk assessment of fluorine and cadmium in rice, corn, and wheat grains in most karst regions of Guizhou province, China

The pollution status of crops planted in Guizhou province of Southwestern China with high background values of Fluorine (F) and Cadmium (Cd) has attracted people’s concern. The present study aimed to investigate the spatial distributions of F and Cd in rice, corn and wheat grains, and further evaluate their health risks to residents in Guizhou province. The contents of F and Cd were measured by fluoride ion-selective electrode and inductively coupled plasma mass spectrometry (ICP-MS) methods, respectively. Additionally, the inverse distance weighted (IDW) technique was conducted to analyze spatial distribution, and the health risk was estimated by target hazard quotient (THQ) and hazardous index (HI). The results indicate that Cd contents in samples varied from 0.000 to 0.463 for rice, 0.000 to 0.307 for corn, and 0.012 to 0.537 (mg/kg) for wheat, while F contents ranged from 0.825 to 5.193 (rice), 0.946 to 8.485 (corn), and 0.271 to 9.143 (wheat) mg/kg. The Cd exceeding ratios were 11.600% for rice, 13.500% for corn, and 45.100% for wheat grains, respectively. In terms of spatial distribution, high levels of F and Cd in rice were found in the northern and central in Guizhou, while Cd in corn was distributed in the eastern and F in corn were distributed in the west area of Guizhou. Moreover, the high levels of F and Cd in wheat were distributed in the western and eastern areas. The mean carcinogenic risks (R) of Cd in rice, corn, and wheat in children were 4.150 × 10^–4, 1.670 × 10^–4 and 3.470 × 10^–4, respectively, and that in adults were 3.430 × 10^–4, 0.471 × 10^–4, and 2.190 × 10^–4, respectively. The HI for adults in rice, corn and wheat grains were 0.756, 0.154, and 0.514, respectively, and that for children were 0.913, 0.549, and 0.814, respectively. Collectively, the potential risks produced by F and Cd to the local residents should not be ignored.

Ecological risk and health risk analysis of soil potentially toxic elements from oil production plants in central China

In this study, the enrichment factor (EF) and pollution load index (PLI) were used to evaluate the pollution of potential toxic elements (PTEs) in the soil near the oil production plants in central China, and the potential ecological risk (PER) and human health risk (HHR) assessment model were used to evaluate the PER and HHR caused by the soil PTEs in the study area. The mean EFs of all PTEs were greater than 1, PTEs have accumulated to varying degrees, especially Cr, Ni and Pb were the most serious. The average value of PLI was 2.62, indicating that the soil PTEs were seriously polluted. The average [Formula: see text] values of PTEs were Cr > Pb > Cd > Ni > As > Cu > Zn > Mn, of which Cr, Pb, Cd and Ni were at medium and above PER levels. Both adults and children in the study area suffered from varying degrees of non-carcinogenic and carcinogenic risks. The total hazard index (THI) values of children (7.31) and adults (1.03) were all > 1, and the total carcinogenic risk index (TCRI) of children (9.44E-04) and adults (5.75E-04) were also > 10-4. In particular, the hazardous quotient (HQ) of Cr and Pb for children under the oral intake route were 4.91 and 1.17, respectively, caused serious non-carcinogenic risk. And the carcinogenic risk index (CRI) values of the PTEs in adults and children under the three exposure routes were Cr > Ni >  > As > Pb >  > Cd. Among them, the CRI values of Cr and Ni in children and adults by oral intake were both greater than 10-4, showing a strong carcinogenic risk. The results will provide scientific basis for environmental protection and population health protection in this area.

Prediction of COPD acute exacerbation in response to air pollution using exosomal circRNA profile and Machine learning

Ambient fine particulate matter (PM2.5) is linked to an increased risk of chronic obstructive pulmonary disease (COPD) exacerbations, which significantly increase the risk of mortality in COPD patients. Identifying the subtype of COPD patients who are sensitive to environmental aggressions is necessary. Using in vitro and in vivo PM2.5 exposure models, we demonstrate that exosomal hsa_circ_0005045 is upregulated by PM2.5 and binds to the protein cargo peroxiredoxin2, which functionally aggravates hallmarks of COPD by recruiting neutrophil elastase and triggering in situ release of tumor necrosis factor (TNF)-α by inflammatory cells. The biological function of hsa_circ_0005045 associated with aggravation of COPD is validated using exosome-transplantation and conditional circRNA-knockdown murine models. By sorting the major components of PM2.5, we find that PM2.5-bound heavy metals, which are distinguishable from the components of cigarette smoke, trigger the elevation of exosomal hsa_circ_0005045. Finally, using machine learning models in a cohort with 327 COPD patients, the PM2.5 exposure-sensitive COPD patients are characterized by relatively high hsa_circ_0005045 expression, non-smoking, and group C (mMRC 0-1 (or CAT < 10) and ≥ 2 exacerbations (or ≥ 1 exacerbation leading to hospital admission) in the past year). Thus, our results suggest that environmental reduction in PM2.5 emission provides a targeted approach to protecting non-smoking COPD patients against air pollution-related disease exacerbation.

Health risks of PM2.5-bound polycyclic aromatic hydrocarbon (PAH) and heavy metals (PPAH&HM) during the replacement of central heating with urban natural gas in Tianjin, China

To investigate the health effects of fine particulate matter (≤ 2.5 μm in aerodynamic diameter; PM_2.5)-bound heavy metals and polycyclic aromatic hydrocarbons (PAHs) before and after the implementation of the Urban Natural Gas Heating Project (UNGHP), the lifetime cancer risks, hazard quotients (HQs) of heavy metals and PAHs were calculated. Seven kinds of heavy metals (Al, As, Cd, Cr, Mn, Ni and Se) and 12 kinds of PAHs including acenaphthylene (ANY), acenaphthene (ANA), fluoranthene (FLT), pyrene (PYR), chrysene (CHR), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBA), benzo[ghi]perylene (BPE) and indeno[1,2,3-cd]pyrene (IPY) were analyzed and used for the health risk assessments. It was found that HQ of Mn fell from 1.09 in the coal-burning period to 0.72 in the gas-burning period in the suburban area. And lifetime cancer risks of PAHs fell from 35.7 × 10^-6 in the coal-burning period to 17.22 × 10^-6 in the gas-burning period in the urban area. It could be concluded that, during the gas-burning period, downward trends were observed for the lifetime cancer risks and HQs of most kinds of heavy metals and PAHs in all regions of Tianjin compared to those during the coal-burning period. The UNGHP was effective, and we should also take other measures to control the pollution.

Record of heavy metals in Huguangyan Maar Lake sediments: Response to anthropogenic atmospheric pollution in Southern China

The historical atmospheric heavy metal pollution of southern China over the past 200 years was explored by analyzing radiometric dating, heavy metals, and Pb isotopes from a sediment core in Huguangyan Maar Lake. Zn, Cd, Sb, Tl, and Pb in the lake are closely related to anthropogenic activities, while Cr and Ni are mainly derived from the weathering of basalt surrounding the lake. Atmospheric Zn, Cd, Sb, and Tl increased rapidly after 1980, consistent with the local industrial development. The increase of atmospheric Pb in southern China occurred earlier than in other regions of China, with the increase after 1850. War and the use of leaded gasoline were the main causes for the rapid increase in atmospheric Pb during 1910-1950. From 1950 to 2000, the input of Pb from anthropogenic activities decreased gradually due to the stable social environment. After 2000, atmospheric Pb continued to rise due to continued industrial development. The three-end-member model of Pb isotopes indicates that coal combustion is the main source of current atmospheric Pb. The proportion of Pb derived from vehicle exhaust emissions reached a peak in the 1960s, then gradually decreased and further reduced with the ban on leaded gasoline after 2000. These results are important in identifying the sources of atmospheric heavy metal pollution and in formulating pollution control strategies.

PM2.5 induces inflammatory responses via oxidative stress-mediated mitophagy in human bronchial epithelial cells

BACKGROUND

Fine particulate matter (PM_2.5) is a ubiquitous air pollutant, and it has been reported to be closely associated with lung inflammatory injury. In this study, the potential molecular mechanisms underlying PM_2.5-induced cellular inflammation in human bronchial epithelial (BEAS-2B) cells were investigated.

MATERIALS AND METHODS

Ambient PM_2.5 particulates from Suzhou, China, were collected and re-suspended in ultrapure water. Cellular damages, characterized by oxidative stress, mitochondrial injury, and inflammatory cytokine production, were determined in 24 h PM_2.5-treated BEAS-2B cells with or without 3-methyladenine (3-MA; autophagy inhibitor) pretreatment. Biomarkers related to oxidative damage, inflammatory injury and autophagy signaling pathways were also measured.

RESULTS

Uptake of PM_2.5 in BEAS-2B cells induced cellular oxidative damage, mitochondrial injury, and inflammatory responses as indicated by a significant decrease in GSH/GSSG ratio, increased MDA content, dilated mitochondria with loss and rupture of crista, and production of inflammatory cytokines. Activation of Nrf-2/TXNIP-mediated NF-κB and Bnip3L/NIX-dependent mitophagy signaling pathways, as well as accumulation of autophagosomes and autolysosomes, were also observed. A 6 h pretreatment of 3-MA increased PM_2.5-induced oxidative damage and cellular inflammation as indicated by increasing protein levels of HO-1, TXNIP, Bnip3L/NIX and IL-8 gene expression.

CONCLUSIONS

PM_2.5 induced cellular inflammatory injury by oxidative stress, mitochondrial dysfunction, and mitophagy initiation. Although induction of Bnip3L/NIX-mediated mitophagy in BEAS-2B cells appeared to confer protection in response to PM_2.5, dysfunction of autophagic flux may be a critical contributor to defective mitophagy and cellular inflammatory response.

Pollution characteristics and human health risk assessments of toxic metals and particle pollutants via soil and air using geoinformation in urbanized city of Pakistan

Toxic metals and particle pollutants in urbanized cities have significantly increased over the past few decades mainly due to rapid urbanization and unplanned infrastructure. This research aimed at estimating the concentration of toxic metals and particle pollutants and the associated risks to public health across different land-use settings including commercial area (CA), urban area (UA), residential area (RA), and industrial area (IA). A total of 47 samples for both soil and air were collected from different land-use settings of Faisalabad city in Pakistan. Mean concentrations of toxic metals such as Mn, Zn, Pb, Ni, Cr, Co, and Cd in all land-use settings were 92.68, 4.06, 1.34, 0.16, 0.07, 0.03, and 0.02 mg kg^-1, respectively. Mean values of PM₁₀, PM_2.5, and Mn in all land-use settings were found 5.14, 1.34, and 1.9 times higher than the World Health Organization (WHO) guidelines. Mn was found as the most hazardous metal in terms of pollution load index (PLI) and contamination factor (CF) in the studied area. Health risk analysis for particle pollutants using air quality index (AQI) and geoinformation was found in the range between good to very critical for all the land-use settings. The hazard quotient (HQ) and hazard index (HI) were higher for children in comparison to adults, suggesting that children may be susceptible to potentially higher health risks. However, the cancer risk (CR) value for Pb ingestion (1.21 × 10^-6) in children was lower than the permissible limit (1 × 10^-4 to 1 × 10^-6). Nonetheless, for Cr inhalation, CR value (1.09 × 10^-8) was close to tolerable limits. Our findings can be of valuable assistance toward advancing our understanding of soil and air pollutions concerning public health in different land-use settings of the urbanized cities of Pakistan.

Spatial distribution of PM2.5-bound elements in eighteen cities over China: policy implication and health risk assessment

In this study, 30 elements in fine particulate matter (PM_2.5) were measured in 18 Chinese cities in 2013. Elemental pollution in northern, southwest, and central China were severe, attributing to excessive coal and biomass combustion in these regions. The concentrations of S, Cl, and K in these areas were 8.21 ± 3.90, 4.03 ± 1.96, and 1.59 ± 0.613 μg/m³, respectively, which were 1.6-2.7 times higher than those in other regions of China. In addition, the industrial emissions in northeast and north China were large, leading to the elevated heavy metal concentration of 1.32 ± 1.17 μg/m³, especially Zn, Pb, Cr, Cd, and Br. Soil dust was the highest in northwest China among the five regions with the concentration of crustal elements of 6.37 ± 4.51 μg/m³. Moreover, although the levels of elemental concentration in east and southeast China were relatively acceptable, regulators must pay attention to elevated level of V (0.009 ± 0.006 μg/m³) in these areas. Compared with 2003, several elements have deteriorated in some cities. For example, As increased by 70%, 18%, and 155% in Changchun, Beijing, and Jinchang, respectively. However, ~ 77% measured elements, e.g., Ti, Fe, and Pb markedly reduced in 2013, with reduction rates of 13-81%. These indicate that the government's policies related to particle-bound elements have shown certain positive environmental effects. For the health risks from the heavy metals in 2013, the non-cancer risks of As and Cd must not be neglected. The cancer risks of As and Pb were much higher than the international safety limit (10^-4). More prominent health risks were found in southwest, central, and northwest China. Therefore, the government should accelerate the shift to cleaner energy in underdeveloped areas of China to obtain more environmental and health benefits.

Concentrations, Source Characteristics, and Health Risk Assessment of Toxic Heavy Metals in PM2.5 in a Plateau City (Kunming) in Southwest China

To explore the mass concentration levels and health risks of heavy metals in the air in dense traffic environments, PM_2.5 samples were collected at three sites in the city of Kunming in April and October 2013, and January and May 2014. Ten heavy metals––V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb––were analyzed by ICP–MS, and the results showed PM_2.5 concentrations significantly higher in spring and winter than in summer and autumn, especially for Zn and Pb. The concentration of heavy metals on working days is significantly higher, indicating that vehicle emissions are significant contributors. An enrichment factor analysis showed that Cr, Mn, Ni, Cu, Zn, As, Cd and Pb come mainly from anthropogenic sources, while V and Co may be both anthropogenic and natural. The correlation and principal component analysis (PCA) showed that Ni, Cu, Zn, Cd and Pb mainly come from vehicles emissions and metallurgical industries; Cr and Mn, from vehicles emissions and road dust; and As, mainly from coal combustion. The health risk assessment shows that the non-carcinogenic risk thresholds of the heavy metals in PM_2.5 to children and adult men and women are all less than 1. The carcinogenic risk of Cr for men and women in traffic-intensive areas exceeds 10⁻⁴, reaching 1.64 × 10⁻⁴ and 1.4 × 10⁻⁴, respectively.

Toxic metals in outdoor/indoor airborne PM2.5 in port city of Northern, China: Characteristics, sources, and personal exposure risk assessment

Outdoor and indoor PM_2.5 samples were simultaneously collected over four seasons (2017-2018) in Caofeidian, China, and analyzed for 15 elements to investigate the characteristics, sources, and health risks of PM_2.5-bound metals. Source-specific PM_2.5-bound metals were analyzed using positive matrix factorization, combined with the conditional probability function and potential source contribution function model. The health risks were evaluated using the health risk assessment model, which included the exposure parameters of indoor and outdoor activities of Chinese residents. The annual median of PM_2.5 concentrations (89.68 μg/m³) and total metals (2.67 μg/m³) from the outdoor samples significantly surpassed that of the indoor samples (51.56 μg/m³) and total metals (1.51 μg/m³) (P < 0.05). In addition, the indoor/outdoor concentration ratios indicated that most indoor metals mainly originated from outdoor emission sources. In the annual analysis of PM_2.5-bound metal sources, this study identified five metal sources: coal combustion, resuspended dust, traffic emissions, fuel combustion sources, and industrial sources, among which industry sources (36.6%) contributed the most. The non-carcinogenic risks of metals for adults (2.81) and children (2.80) all exceed the acceptable non-carcinogenic risk level (1). The non-carcinogenic risk of Mn (1.46 for children, 1.48 for adults) was a key factor in the total non-carcinogenic risk. The total carcinogenic risk of metals for children (3.75 × 10^-5) was above the acceptable level (1.0 × 10^-6) but within the tolerant limit (1.0 × 10^-4), and that for adults (1.48 × 10^-4) was above the tolerant limit. The lifetime carcinogenic risk of Cr⁶⁺ had the highest proportion of the total carcinogenic risk for children (87.5%) and adults (87.8%). Our results revealed that both adults and children suffered carcinogenic and non-carcinogenic risks from the PM_2.5-bound metals in Caofeidian. The corresponding emission control measures of metals in atmosphere should be considered.

Temporal variations of levels and sources of health risk associated with heavy metals in road dust in Beijing from May 2016 to April 2018

To analyze the temporal variations of heavy metals, health risk, and source-specific health risk, 24 road dust samples were collected from Beijing in each month in two years. The temporal variations of Hg, Pb, and Ni were higher than other heavy metals. Most heavy metals reached their highest concentrations either in winter or in spring, then the concentrations decreased and reached the lowest values in autumn. Human health risk assessment (HHRA) model showed that As, Cr, and Ni might pose cautionary carcinogenic risk (CR) to children (CR > 10^-6). CR for adults were only 0.15 to 0.19 times of that for children. Four sources were identified based on positive matrix factorization model and HHRA model, they were traffic exhaust, fuel combustion, construction, and use of pesticides and fertilizers. Influenced by the difference of carcinogenicity of heavy metals, traffic exhaust contributed the largest to heavy metals (36.02%, over 42.24% higher than other sources), while contributions of fuel combustion to CR (36.95%) was similar to traffic exhaust (37.17%). Monte-Carlo simulation showed that the 95th percentile of probability density functions of CR posed by Cr and Ni from each source were 9.90 × 10^-5 to 2.64 × 10^-4, posing cautionary carcinogenic risk to children. The seasonal change of CR varied among different sources. CR from use of pesticides and fertilizers in spring was 35.06 times of that in winter, and that from fuel combustion in winter was 1.15-2.40 times of that in other seasons. CR from each source was sensitive to ingestion rate and skin adherence factor.

Characterization of ambient PM1 at a suburban site of Agra: chemical composition, sources, health risk and potential cytotoxicity

The present study was conducted at a University campus of Agra to determine concentrations of crustal and trace elements in submicron mode (PM₁) particles to reveal sources and detrimental effects of PM₁-bound metals (Cr, Cd, Mn, Zn, As, Co, Pb, Cu and Ni) in samples collected in the foggy (1 December 2016-17 January 2017) and non-foggy periods (1 April 2016-30 June 2016). Samples were collected twice a week on preweighed quartz fibre filters (QM-A 47 mm) for 24 h using Envirotech APM 577 (flow rate 10 l min^-1). Mass concentration of PM₁ was 135.0 ± 28.2 and 54.0 ± 18.5 µg/m³ during foggy and non-foggy period, respectively; crustal and trace elements were 13 and 4% during foggy and 11 and 3% in the non-foggy period. Source identification by PCA (principal component analysis) suggested that biomass burning and coal combustion was the prominent sources in foggy period followed by resuspended soil dust, industrial and vehicular emission, whereas in non-foggy period resuspended soil dust was dominant followed by biomass burning and coal combustion, industrial and vehicular emissions. In both episodes, Mn has the highest Hq (hazard quotient) value and Cr has the highest IlcR (Incremental Lifetime Cancer Risk) value for both adults and children. In vitro cytotoxicity impact on macrophage (J774) cells was also tested using MTT assay which revealed decreasing cell viability with increasing particle mass.

Characterization, Pollution Sources, and Health Risk of Ionic and Elemental Constituents in PM2.5 of Wuhan, Central China

Atmospheric PM2.5 samples from Wuhan, China were collected during a winter period of February and a summer period of August in 2018. The average PM2.5 mass concentration in winter reached 112 μg/m3—about two-fold higher than that found in summer. Eight ionic species constituted 1/3 of PM2.5, whereas more than 85% represented secondary ionic aerosols (NO3−, SO42− and NH4+). Higher ratios of NO3−/SO42− (0.95–2.62) occurred in winter and lower ratios (0.11–0.42) occurred in summer showing the different contribution for mobile and stationary sources. Seventeen elemental species constituted about 10% of PM2.5, with over 95% Na, Mg, Al, Ca, Fe, K and Zn. Higher K-concentration occurred in winter indicating greater contribution from biomass and firework-burning. Carcinogenic risks by Cr, As, Cd, Ni and Pb in PM2.5 indicated that about 6.94 children and 46.5 adults among per million may risk getting cancer via inhalation during surrounding winter atmospheric sampling, while about 5.41 children and 36.6 adults have the same risk during summer. Enrichment factors (EFs) and elemental ratios showed that these hazardous elements were mainly from anthropogenic sources like coal and oil combustion, gasoline and diesel vehicles.

Size characteristics and health risks of inorganic species in PM1.1 and PM2.0 of Shanghai, China, in spring, 2017

Ambient particulates of Shanghai with 5-stage particle sizes were firstly determined in spring, 2017. The particles' mass concentrations were mainly observed in fine particle matter (PM_1.1) and coarse particles (diameter > 7.0 μm). Water-soluble ionic contents were also more distributed in PM_1.1 with the great contents of secondary particles (NO₃^-, SO₄^2-, and NH₄⁺). Higher ratios of NO₂/SO₂ and NO₃^-/SO₄^2- indicated that the vehicle emissions might be made more greater contribution rather than coal combustions to the fine particles. Crustal enrichment factors (EFcs) of trace elements (V, Cr, Ni, Zn, As, Se, Rb, Cd, Pb, and Bi) in PM_1.1 in that called slight air pollution events were always higher than those in that called severe air pollution events and EFcs of Se were up to 2.5 × 10⁴, while EFcs of Pb, Bi, and Cd were over 100. Based on kinds of elemental ratios in PM_1.1 and PM_1.1-2.0, atmospheric pollutants in Shanghai might be mainly from coal and oil combustions, diesel, and gasoline vehicles. Air masses backward trajectories also showed that the air masses from the northern part of China were one important air pollutant origins, but other ones might be the local sources, such as traffic and industries. Based on carcinogenic risk analysis of PM_2.0, it was considerable that 12-60 children and 37-87 adults among millions of people living in Shanghai might be attacked by cancer during their lifetime. Moreover, the great carcinogenic risk was also observed according to the high concentrations of elemental Cr and As in PM_1.1.

Elemental compositions of particulate matter retained on air condition unit's filters at Greater Doha, Qatar

Elemental composition of airborne dust samples retained by internal filters of air condition units (ACUs) was determined at 12 locations of Doha city, state of Qatar. Twenty-four elements: Al, Ca, Mg, Fe, Na, K, Ti, Zn, P, Sr, Mn, Ba, Cu, Cr, Ni, Pb, V, Mo, Li, Co, Sb, As, Cd, Be, were analysed by ICP-OES technique after acid digestion of the samples. The analysed components reflect 20.6% of the total sample mass. Similar or lower concentration values have been found for As, Cd, Cr, Cu, Mn, Ni, Pb, V, Zn, Al, and Fe compared to the international context of upper crust concentrations, NIST SRM (urban dust), published local dust information of outdoor, and surface terrestrial deposit (STD) counted for 7.2, 0.7, 91.8, 192.8, 369.7, 68.6, 65.3, 52.1, 824.3, 19,791, 20,508 mg/kg, respectively. The coefficient of correlation (p ≤ 0.05) showed significant association of ACUs dust elemental compositions with the main components of the local earth crust and surface deposits, ranging from the lowest 0.77 (Mg-Fe) to the highest 0.98 (Al-Fe), while Ni and V, typical anthropogenic pollutants, are also strongly correlated (0.86). These strong correlation relationships can be interpreted as the contribution of outdoor particulate to the indoor dust. Dendrogram of metal/Al ratios, based on Euclidean distance calculation and average linkage clustering method, distinguished three typical groups. Studying the enrichment factors of the three groups indicated elevated levels of Zn (131), Pb (49), Cu (32), Cd (8) and Ni (5) found indoors compared to the background composition of STD especially at locations in the industrial zone. The major elemental composition of the samples reflects the typical mineral composition of the local dust, while the trace composition demonstrates the influence of indoor sources. The collected ACU filter dust samples show significant contribution of outdoor mineral particles, non-exhaust traffic emission, industrial sources, as well as the influence of indoor activity such as smoking.

Characterization, concentration and risk assessment of airborne particles using car engine air filter (case study: Tehran metropolis)

Atmospheric elements released into the atmosphere can enter the human body through inhalation, ingestion and dermal contact and are then deposited in the body. Trace elements have potential risks to human health. For this purpose, the particulate matter accumulated by car air filters (CAFs) was studied. The morphology and distribution of particle size were examined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The concentration of elements in CAFs and CAF-estimated air for 30 elements in Tehran, Iran, was analyzed in winter and summer, from February to July 2017. Samples were determined by inductively coupled mass plasma spectrometry. The most abundantly detected elements in both CAFs and air in both seasons were Ca, Mg, Na and Fe. The shape of the particles was mostly irregular and spherical. Most of the particles were between 0.5 and 1.0 µm. The carcinogenic risks of inhalation exposure to Cr and Co in winter and summer were higher than the acceptable level (< 1 × 10^-4) for children and adults. The carcinogenic risks of As and Cr in both seasons were higher than 1 × 10^-4 for children and adults via dermal contact. Also, the carcinogenic risks of Cr in both seasons of ingestion exposure were higher than 1.00E-04 for children and adults. The integrated noncarcinogenic risks of all trace elements were higher than the safe level (= 1) for children and adults in both seasons.

Trace element characterization of fine particulate matter and assessment of associated health risk in mining area, transportation routes and institutional area of Dhanbad, India

Samples of PM_2.5 were collected on PTFE filters at 11 monitoring stations in Dhanbad, India, from March, 2014, to February, 2015, for the quantification of 10 PM_2.5-bound trace elements by using ICP-OES, source apportionment by using principal component analysis and health risks posed by PM_2.5-bound trace elements by using health risk assessment model developed by US EPA. The average annual PM_2.5 concentration (149 ± 66 µg/m³) exceeded the national ambient air quality standards by factor of 3.7, US EPA national ambient air quality standards by factor of 10 and WHO air quality guidelines by factor of 15. The sum total of average annual concentration of all PM_2.5-bound trace elements was found to be 3.206 µg/m³ with maximum concentrations of Fe (61%), Zn (21%) and Pb (11%). Coal mining, coal combustion, vehicular emission, tyre and brake wear and re-suspension of road dust were identified as dominant sources of PM_2.5-bound trace elements from the results of correlation and chemometric analysis. The significantly high HQ values posed by PM_2.5-bound Co and Ni and intensification of HI values (15.7, 10.8 and 8.54 in mining area, transportation routes and institutional area, respectively) for multielemental exposure indicate high potential of non-carcinogenic health risk associated with inhalation exposure. The carcinogenic health risk due to multielemental exposure in mining area (2.27 × 10^-4) and transportation routes (1.57 × 10^-4) for adults were significantly higher than threshold value indicating the vulnerability of adults toward inhalation-induced carcinogenic risk posed by PM_2.5-bound trace elements.

Maternal exposure to PM2.5 may increase the risk of congenital hypothyroidism in the offspring: a national database based study in China

Background

Maternal exposure to air pollution is related to fetal dysplasia. However, the association between maternal exposure to air pollution and the risk of congenital hypothyroidism (CH) in the offspring is largely unknown.

Methods

We conducted a national database based study in China to explore the association between these two parameters. The incidence of CH was collected from October 1, 2014 to October 1, 2015 from the Chinese Maternal and Child Health Surveillance Network. Considering that total period of pregnancy and consequently the total period of particle exposure is approximately 10 months, average exposure levels of PM_2.5, PM₁₀ and Air Quality Index (AQI) were collected from January 1, 2014 to January 1, 2015. Generalized additive model was used to evaluate the association between air pollution and the incidence of CH, and constructing receiver operating characteristic (ROC) curve was used to calculate the cut-off value.

Results

The overall incidence of CH was 4.31 per 10,000 screened newborns in China from October 1, 2014 to October 1, 2015. For every increase of 1 μg/m³ in the PM_2.5 exposure during gestation could increase the risk of CH (adjusted OR = 1.016 per 1 μg/m³ change, 95% CI, 1.001–1.031). But no significant associations were found with regard to PM₁₀ (adjusted OR = 1.009, 95% CI, 0.996–1.018) or AQI (adjusted OR = 1.012, 95% CI,0.998–1.026) and the risk of CH in the offspring. The cut-off value of prenatal PM_2.5 exposure for predicting the risk of CH in the offspring was 61.165 μg/m³.

Conclusions

The present study suggested that maternal exposure to PM_2.5 may exhibit a positive association with increased risk of CH in the offspring. We also proposed a cut-off value of PM_2.5 exposure that might determine reduction in the risk of CH in the offspring in highly polluted areas.

Bioaccumulation and health risk assessment of trace metals in fish from freshwater polyculture ponds in Chengdu, China

The freshwater polyculture pond culturing occupied an important position in the aquaculture industry. Accumulation of trace metals was investigated in water, sediments, and fish (Carassius auratus, Cyprinus carpio, Ctenopharyngodon idellus) from typical polyculture ponds in Chengdu, China. The results showed most of the pond water in Chengdu were safe for fish cultivation. The Cd and Cr concentrations in sediment samples from sites S3, S4, and S9 which were near the industrial park and road with a high traffic volume were higher than those of the other sites. Cu, Cr, Fe, Zn, Mn, Ni, and Pb in sediments were unpolluted, while Cd was unpolluted to moderately polluted due to anthropogenic activities. Cu, Cd, and Pb in fish pond sediment of Chengdu had higher potential mobility under normal environmental circumstances. The trace metal concentrations in liver of three fish species were all higher than those in muscle tissues. The order of bioaccumulation factor (BAF) values for trace metals was Cr > Cu > Pb > Zn > Cd > Ni > 20. The concentrations of Cu, Cd, Pb, Zn, and Cr in the muscle of three fish species were all below the local and international maximum permissible levels. The target hazard quotient (THQ) and hazard index (HI) of trace metals in aquaculture fish ponds in Chengdu were lower than 1, which indicated that the consumption of grass, crucian, and common carp cultivated in the aquaculture ponds of Chengdu pose no health risk to the residents.

Concentration, sources and human health risk of heavy metals and polycyclic aromatic hydrocarbons bound PM2.5 ambient air, Tehran, Iran

The exposure to heavy metals and polycyclic aromatic hydrocarbons (PAHs) bound to particulate matter 2.5 (PM_2.5) ambient air can result in some adverse health effect. In the current study, PM_2.5 ambient air of Tehran metropolitan, Iran, was characterized by the aid of scanning electron microscope and energy-dispersive X-ray techniques. Also, the human health risk of heavy metals and PAHs bound PM_2.5 for adults and children was assessed using the Monte Carlo simulation method. According to our findings, a size range of 0.97-2.46 μm with an average diameter of 1.56 μm for PM_2.5 was noted. The average concentration of PM_2.5 in ambient air (8.29E+04 ± 2.94E+04 ng m^-3) significantly (p < 0.05) was suppressed the national (2.50E+04 ng m^-3), World Health Organization (2.50E+04 ng m^-3) and Environmental Protection Agency (3.50E+04 ng m^-3) standard limits. The rank order of heavy metals bound PM_2.5 was determined as Al > Cu > Cd > Cr > Pb > Ni > Fe > Mn. The maximum concentration among 16 PAHs compounds investigated was correlated with Phenanthrene. Considering the principal component analysis, the main source of heavy metals (Ni, Pb and Cr) is vehicle combustion. Moreover, the rank order of exposure pathways based on their health risk was ingestion > inhalation > dermal contact. Moreover, the significant health risks for Tehran residents due to heavy metals bound PM_2.5 [target hazard quotient > 1; carcinogenic risk > 1.00E-06)] were noted based on the health risk assessment. Excessive carcinogenic risk (ECR) of PAHs bound PM_2.5 was 4.16E-07 that demonstrated that there is no considerable risk (ECR < 1.00E-06).

Summer-winter differences of PM2.5 toxicity to human alveolar epithelial cells (A549) and the roles of transition metals

Atmospheric fine particulate matters (PM_2.5) induce adverse human health effects through inhalation, and the harmful effects of PM_2.5 are determined not only by its air concentrations, but also by the particle components varied temporally. To investigate seasonal differences of the aerosol toxicity effects including cell viability and membrane damage, cell oxidative stress and responses of inflammatory cytokines, the human lung epithelial cells (A549) were exposed to PM_2.5 samples collected in both summer and winter by the in vitro toxicity bioassays. Toxicological results showed that, the PM_2.5 led to the cell viability decrease, cell membrane injury, oxidative stress level increase and inflammatory responses in a dose-dependent manner. Temporally, the cytotoxicity of winter PM_2.5 was higher than summer of this studied industrial area of Nanjing, China. According to the different contents of heavy metals accumulated in PM_2.5, the transition metals such as Cu might be an important contributor to the aerosol cell toxicity.

Heavy metals and their source identification in particulate matter (PM2.5) in Isfahan City, Iran

The presence of heavy metals (HMs) in particulate matters (PMs) particularly fine particles such as PM_2.5 poses potential risk to the health of human being. The purpose of this study was to analyze the contents of HMs in PM_2.5 in the atmospheric monitoring stations in Isfahan city, Iran, in different seasons between March 2014 and March 2015 and their source identification using principle component analysis (PCA). The samples of PM_2.5 were taken using a high volume sampler in 7 monitoring stations located throughout the city and industrial zones since March 2014 to March 2015. The HMs content of the samples was measured using ICP-MS. The results showed that the concentrations of As, Cd and Ni were in a range of 23-36, 1-12, and 5-76ng/m³ at all the stations which exceeded the US-EPA standards. Furthermore, the concentrations of Cr and Cu reached to 153 and 167ng/m³ in some stations which were also higher than the standard levels. Depending on the potential sources of HMs, their concentration in PM_2.5 through the various seasons was different. PCA illustrated that the different potential sources of HMs in the atmosphere, showing that the most important sources of HMs originated from fossil fuel combustion, abrasion of vehicle tires, industrial activities (e.g., iron and steel industries) and dust storms. Management and control of air pollution of industrial plants and vehicles are suggested for decreasing the risk of the HMs in the region.

Chemical fractionation and health risk assessment of particulate matter-bound metals in Pune, India

The present study deals with the assessment of sequential extraction of particulate matter (PM)-bound metals and the potential health risks associated with them in a growing metropolitan city (Pune) of India. The average mass concentration of both PM_2.5-10 and PM_2.5 exceeded the National Ambient Air Quality Standards. Significant seasonal variation in mass concentration was found for both size fractions of PM with higher values in winter season and lower in monsoon. Chemical species of the studied trace metals in PM exhibited significant differences, due to difference in sources of pollution. Metals such as Cd, Pb, and Cr in both size fractions and Zn and Co in fine fraction were more efficiently extracted in mobile fractions showing their mobile nature while Ni and Fe showed reduced mobility. Fe showed the highest concentrations among all the analyzed elements in both coarse (PM_2.5-10) and fine (PM_2.5) PM, while Cd showed least concentration in both size fractions. PCA identified industrial emissions, vehicular activity, coal combustion, diesel exhaust, waste incineration, electronic waste processing, constructional activities, soil, and road dust as probable contributors responsible for the metallic fraction of PM. All the metals showed varying contamination in PM samples. The contamination was higher for fine particles than coarse ones. The average global contamination factor was found to be 27.0-34.3 in coarse and fine PM, respectively. The hazard quotient (HQ) estimated for Cd, Co, and Ni (both total and easily accessible concentrations) exceeded the safe level (HQ = 1), indicating that these metals would result in non-carcinogenic health effects to the exposed population. The HQ ranged from 9.1 × 10^-5 for Cu (coarse) to 8.3 for Ni (fine) PM. The cancer risk for Cd, Ni, and Cr in both sized PM were much higher than the acceptable limits of USEPA.

In vitro bioaccessibility and health risk assessment of heavy metals in atmospheric particulate matters from three different functional areas of Shanghai, China

The bioaccessibility and human health risks of heavy metals in PM_2.5 and PM₁₀ samples from three functional areas of Shanghai, China including a commercial area (CA), a residential area (RA), and an industrial area (IA), were investigated. Gamble's solution and physiologically based extraction test were employed to simulate human respiratory and digestive system, respectively. Both PM_2.5 and PM₁₀ concentration in the three areas exceeded the guideline of WHO, and followed the order of IA>CA≈RA. Zinc and Pb were the most abundant metals with a concentration range of 0.19-0.44 and 0.05-0.42μgm^-3, respectively. In respiratory system, heavy metal bioaccessibility for PM_2.5 and PM₁₀ varied within the range of 5.3%-71.4% and 4.8%-51.5%, respectively. Heavy metals in RA showed higher bioaccessibility than those in CA and IA in the respiratory system. In digestive system, heavy metal bioaccessibility for PM_2.5 and PM₁₀ reached 24.6%-90.9% and 28.5%-88.9% in the gastric phase and was reduced to 8.7%-85.5% and 8.5%-81.8% in the intestinal phase, respectively. The bioaccessibility of heavy metals in CA was highest among three areas in the digestive system. Based on the bioaccessibility analysis, the hazard quotient values of heavy metals in PMs via inhalation exposure were far below 1, the safe level, for both adults and children. However, potential risks via ingestion exposure resulted from Pb existed for children of three areas and for adults of RA as their hazard quotient values could reach up to 11. The obtained results indicated that the air quality in Shanghai need to be improved and the health risks to humans via ingestion exposure to atmospheric Pb must be considered.

Comparison of chemical compositions in air particulate matter during summer and winter in Beijing, China

The development of industry in Beijing, the capital of China, particularly in last decades, has caused severe environmental pollution including particulate matter (PM), dust-haze, and photochemical smog, which has already caused considerable harm to local ecological environment. Thus, in this study, air particle samples were continuously collected in August and December, 2014. And elements (Si, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Cd, Ba, Pb and Ti) and ions ([Formula: see text], [Formula: see text], F^-, Cl^-, Na⁺, K⁺, Mg²⁺, Ca²⁺ and [Formula: see text]) were analyzed by inductively coupled plasma mass spectrometer and ion chromatography. According to seasonal changes, discuss the various pollution situations in order to find possible particulate matter sources and then propose appropriate control strategies to local government. The results indicated serious PM and metallic pollution in some sampling days, especially in December. Chemical Mass Balance model revealed central heating activities, road dust and vehicles contribute as main sources, account for 5.84-32.05 % differently to the summer and winter air pollution in 2014.

Hazard posed by metals and As in PM2.5 in air of five megacities in the Beijing-Tianjin-Hebei region of China during APEC

Airborne fine particulate matter (PM2.5) from five megacities including Beijing, Tianjin, Shijiazhuang, Baoding, and Jinan were collected during November 2014 and compared with similar periods in 2012 and 2013. The November 2014 period coincided with the Asia Pacific Economic Cooperation (APEC) Leaders Meeting during which measures to control pollution of the air were introduced. Concentrations of 11 elements in PM2.5 were quantified by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave-assisted digestion. Potential effects of five toxic trace metals including Mn, Ni, Cu, Zn, Pb, and the metalloid As on health were assessed. In 2014, concentrations of PM2.5 were significantly less than during the same period in 2012 and 2013. Mean concentrations of six elements ranked in decreasing order, Zn > Pb > Cu ≈ Mn > As > Ni, and spatial concentrations ranked in decreasing order, Shijiazhuang > Baoding > Tianjin > Jinan > Beijing. Risks of the five metals and the metalloid As to health of humans were small, except for Mn in Shijiazhuang. Risks to health posed by other elements were less during the period of study. Risks posed by the five metals and As in Beijing were greater to varying degrees after the APEC meeting. Risks to health of humans during the APEC were overall lesser than the same period in 2012 and 2013, mostly due to lesser emissions due to the short-term control measures.

A Longitudinal Study of Association between Heavy Metals and Itchy Eyes, Coughing in Chronic Cough Patients: Related with Non-Immunoglobulin E Mediated Mechanism

The association between heavy metals exposure and respiratory diseases or allergic sensitization showing high serum immunoglobulin E (IgE) has been suggested. However, previous findings have been inconsistent and the mechanisms responsible remain unclear. We evaluated heavy metal exposure and its association with coughing, itchy eyes in chronic cough patients with different IgE levels. Ninety outpatients in Kanazawa University Hospital were recruited between January-June 2011. Subjects whose total IgE measured by radioimmunosorbent test were asked to record their daily symptoms. We collected daily total suspended particles (TSP) from which concentrations of calcium (Ca), cadmium (Cd), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), and lead (Pb) were determined then divided into high and low level groups. Generalized estimating equations were applied to compute the relationship between concentrations of these metals and symptoms. All metals at high levels were significantly associated with itchy eyes compared with low levels, with exception of Ca, the six others were significant in patients with IgE < 250 IU/mL. Cd, Fe, Mn had association with coughing (odds ratio-OR (95% confidence interval-CI): 1.13 (1.03, 1.24), 1.22 (1.05, 1.42), and 1.13 (1.01, 1.27), respectively), this relationship remained significant for Cd (OR (95% CI): 1.14 (1.03, 1.27)) and Mn (OR (95% CI): 1.15 (1.00, 1.31)) in patients with lower IgE. Our findings demonstrate the relationship between aerial heavy metals and itchy eyes, coughing in chronic cough patients, suggesting these symptoms may be due to a non-IgE mediated mechanism.