Levels and Sources of PAHs in Air-borne PM2.5 of Hefei City, China

Characteristics, sources and health risk assessment of trace metals and polycyclic aromatic hydrocarbons in PM2.5 from Hefei, China

Trace metals (TRs) and polycyclic aromatic hydrocarbons (PAHs) are major toxic components of fine particulate matter (PM2.5) and related to various health adverse outcomes. The study aims to get a better understanding of the contents, sources and risks of PM2.5-bounded TRs and PAHs in Hefei, China, during the period of 2019-2021. We collected 504 samples and measured twelve TRs and sixteen priority PAHs by inductively coupled plasma mass spectrometry and high-performance liquid chromatography. The annual mass concentrations of PM2.5 was fluctuated in the year of 2019-2021 at 50.95, 47.48 and 59.38 μg/m3, with seasonal variations in rank order of winter > spring > autumn > summer. The median concentrations of PM2.5-bounded ƩTRs and ƩPAHs were also fluctuated, 132.85, 80.93 and 120.27 ng/m3 for ƩTRs, 2.57, 5.85 and 2.97 ng/m3 for ƩPAHs, in the year of 2019, 2020 and 2021, respectively. Seasonal variations of ƩTRs and ƩPAHs show the highest concentration in winter. Positive matrix factorization was used for identified pollution emission sources, and TRs mainly originated from coal combustion, traffic emission and fugitive dust, while PAHs stemmed from biomass, diesel, gasoline and coal combustion. Health risk assessment indicated that adults were more vulnerable than children, the carcinogenic risk assessment of As and Cr manifested a certain degree of cancer risk (1.0 × 10-6 < CR < 1.0 × 10-4) in adults group, and health risks of TRs were higher than PAHs in Hefei. These findings suggest that PM2.5-bounded TRs and PAHs should be considered when making emission control strategies for air pollution, and winter, combustion sources and adults should achieve more policy attention to decrease exposure risks in Hefei.

Associations of polycyclic aromatic hydrocarbons, water-soluble ions and metals in PM2.5 with liver function: Evidence from schizophrenia cohort

BACKGROUND

Fine particulate matter (PM_2.5) was reported to impact liver function, but the roles of specific PM_2.5 chemical components remained to be explored. Besides, severe liver dysfunction in schizophrenia patients deserves attention.

OBJECTIVE

To investigate the associations of short-term PM_2.5 components with liver function in schizophrenia patients.

METHODS

A repeated-measures study based on schizophrenia cohort including 1023 visits (n = 446) was conducted during 2017-2020. Liver function was reflected by 10 indicators including liver enzymes, proteins and bilirubin et al. Monitoring data of PM_2.5 and its components, including 16 polycyclic aromatic hydrocarbons (PAHs), 4 water-soluble ions and 10 metals were collected. Linear mixed effect and Bayesian kernel machine regression (BKMR) models were used to evaluate the single and combined effects of PM_2.5 components (0-3 day) on liver function in schizophrenia patients.

RESULTS

Several PAHs were significantly associated with liver enzymes, while water-soluble ions and metal components had almost no association. Specifically, with per interquartile range (IQR) increased in Fluoranthene, levels of alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and gamma-glutamyl transpeptidase (GGT) increased by 2.06 %, 5.07 %, 4.94 % and 5.56 %, respectively. An IQR increases in Benzo[a]pyrene was significantly associated with 6.62 %, 3.67 % and 7.83 % increase in ALT, AST and GGT. Almost all PAHs, sulfate, nitrate, ammonium, Sb, Al, As, Pb, Mn and Tl were positively associated with albumin (ALB). Phenanthrene was associated with increased levels of direct bilirubin (DBIL) and total bilirubin (TBIL). The combined effects of significant PM_2.5 components on ALP, GGT, ALB, globulin (GLOB), ratio of albumin to globulin (A/G), TBIL and total bile acid (TBA) were found by BKMR, respectively.

CONCLUSIONS

Findings highlight the short-term combined effects of PM_2.5 components, especially PAHs, on liver function in schizophrenia patients, which contribute to the management of PM_2.5 sources including combustion activities and traffic emissions as well as improving schizophrenia comorbidities.

PM2.5 chemical composition and health risks by inhalation near a chemical complex

Particulate matter (PM_2.5) samples were collected in the vicinity of an industrial chemical pole and analysed for organic and elemental carbon (OC and EC), 47 trace elements and around 150 organic constituents. On average, OC and EC accounted for 25.2% and 11.4% of the PM_2.5 mass, respectively. Organic compounds comprised polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, anhydrosugars, phenolics, aromatic ketones, glycerol derivatives, aliphatic alcohols, sterols, and carboxyl groups, including aromatic, carboxylic and dicarboxylic acids. Enrichment factors > 100 were obtained for Pb, Cd, Zn, Cu, Sn, B, Se, Bi, Sb and Mo, showing the contribution of industrial emissions and nearby major roads. Principal component analysis revealed that vehicle, industrial and biomass burning emissions accounted for 66%, 11% and 9%, respectively, of the total PM_2.5-bound PAHs. Some of the detected organic constituents are likely associated with plasticiser ingredients and thermal stabilisers used in the manufacture of PVC and other plastics in the industrial complex. Photooxidation products of both anthropogenic (e.g., toluene) and biogenic (e.g., isoprene and pinenes) precursors were also observed. It was estimated that biomass burning accounted for 13.8% of the PM_2.5 concentrations and that secondary OC represented 37.6% of the total OC. The lifetime cancer risk from inhalation exposure to PM_2.5-bound PAHs was found to be negligible, but it exceeded the threshold of 10^-6 for metal(loi)s, mainly due to Cr and As.

The Effect of Urban Green Spaces on Reduction of Particulate Matter Concentration

In an urban scenario, one of the air pollutants most harmful to human health and environmental is the particulate matter (PM). Considering that urban green areas can contribute to mitigating the effects of PM, this work compares the concentration of PM_2.5 in two closer locations in Rio de Janeiro, in order to verify how vegetation cover can actually improve air quality. One is the entrance to the Rebouças Tunnel (RT) and the other is the Rio de Janeiro Botanical Garden (RJBG). For this purpose, PM_2.5 samples were taken from September 2017 to March 2018 using a Large Volume Sampler (LVS). The results reveal that RT has a higher concentration of PM_2.5 in almost all samples. The RJBG obtains concentrations around 33% less than the other area, suggesting that the presence of urban green areas like the RJBG can reduce PM_2.5 levels when compared to places with less vegetation cover, providing better air quality.

Polycyclic aromatic hydrocarbons in airborne particulate matter samples from Hanoi, Vietnam: Particle size distribution, aryl hydrocarbon ligand receptor activity, and implication for cancer risk assessment

Concentrations and profiles of unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) were analyzed in airborne particulate matter (PM) samples collected from high-traffic roads in Hanoi urban area. Levels of PAHs and Me-PAHs ranged from 210 to 660 (average 420) ng/m³ in total PM, and these pollutants were mainly associated with fine particles (PM_2.5) rather than coarser ones (PM _> 10 and PM₁₀). Proportions of high-molecular-weight compounds (i.e., 5- and 6-ring) increased with decreasing particle size. Benzo[b+k]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene were the most predominant compounds in the PM_2.5 samples. In all the samples, Me-PAHs were less abundant than unsubstituted PAHs. The PAH-CALUX assays were applied to evaluate aryl hydrocarbon receptor (AhR) ligand activities in crude extracts and different fractions from the PM samples. Benzo[a]pyrene equivalents (BaP-EQs) derived by the PAH-CALUX assays for low polar fractions (mainly PAHs and Me-PAHs) ranged from 300 to 840 ng/m³, which were more consistent with theoretical values derived by using PAH-CALUX relative potencies (270-710 ng/m³) rather than conventional toxic equivalency factor-based values (22-69 ng/m³). Concentrations of PAHs and Me-PAHs highly correlated with bioassay-derived BaP-EQs. AhR-mediated activities of more polar compounds and interaction effects between PAH-related compounds were observed. By using PAH-CALUX BaP-EQs, the ILCR values ranged from 1.0 × 10^-4 to 2.8 × 10^-4 for adults and from 6.4 × 10^-5 to 1.8 × 10^-4 for children. Underestimation of cancer risk can be eliminated by using effect-directed method (e.g., PAH-CALUX) rather than chemical-specific approach.

Analysis of Polycyclic Aromatic Hydrocarbon in Airborne Particulate Matter Samples by Gas Chromatography in Combination with Tandem Mass Spectrometry (GC-MS/MS)

Polycyclic aromatic hydrocarbons (PAHs), the family of organic contaminations, have been shown to have negative effects on human health. However, until now, the comprehension on occurrence, distribution, and risk assessment of human exposure to PAHs has been limited in Vietnam. In this work, a capillary gas chromatography coupled with electron impact ionization tandem mass spectrometry (GC-EI-MS/MS) has been introduced for analysis of 16 PAHs in some particulate matter samples. PAHs have been separated on the TG 5 ms capillary gas chromatographic column and detected by tandem mass spectrometry in multiple reaction monitoring mode. The PAHs in the particulate matter (PM 2.5 and PM 10) samples were extracted by ultrasonic-assisted liquid extraction and cleaned up by an acidic silica gel solid phase extraction. The linearity range of all analyzed PAHs was from 5 to 2000 ng mL^-1 with R ² ≥0.9990. Limit of detection (LOD) of PAHs in particulate matter sample was from 0.001 ng m^-3 (Br-Naph) to 0.276 ng m^-3 (Fln). The recovery of PAHs was investigated by international proficiency testing samples. The recoveries of PAHs in proficiency testing sample ranged from 79.3% (Chr) to 109.8% (IcdP). The in-house validated GC-EI-MS/MS method was then applied to analysis of some particulate matter samples that were collected in the Hanoi areas. The total concentrations of PAHs in several brands of samples collected from Hanoi were found in the range of 226.3 ng m^-3-706.43 ng m^-3. Among the studied compounds, naphthalene was found at high frequency and ranged from 106.5 ng m^-3 to 631.1 ng m^-3. The main distribution of the PAHs in particulate matter samples was two-ring and three-ring compounds.

Molecule-Resolved Visualization of Particulate Matter on Human Skin Using Multimodal Nonlinear Optical Imaging

Precise measurement of particulate matter (PM) on skin is important for managing and preventing PM-related skin diseases. This study aims to directly visualize the deposition and penetration of PM into human skin using a multimodal nonlinear optical (MNLO) imaging system. We successfully obtained PM particle signals by merging two different sources, C–C vibrational frequency and autofluorescence, while simultaneously visualizing the anatomical features of the skin via keratin, collagen, and elastin. As a result, we found morphologically dependent PM deposition, as well as increased deposition following disruption of the skin barrier via tape-stripping. Furthermore, PM penetrated more and deeper into the skin with an increase in the number of tape-strippings, causing a significant increase in the secretion of pro-inflammatory cytokines. Our results suggest that MNLO imaging could be a useful technique for visualizing and quantifying the spatial distribution of PM in ex vivo human skin tissues.

Biomonitoring of heavy metal contamination with roadside trees from metropolitan area of Hefei, China

Air and dust borne heavy metals can be deposited and bioaccumulated by plants; therefore, biomonitoring employing plants is an effective tool for environmental impact assessment in urban environments. In this study, in addition to road dust, leaves and bark were collected from four common tree species at roadside and urban park sampling sites within the metropolitan area of Hefei, China. A range of heavy metals were analyzed by ICP-MS and AFS. The metal accumulation index (MAI) was adopted to compare the bioaccumulation capacity. Results showed that Cd was highly enriched in road dust although its abundance was low in comparison with that of other elements. The MAI values presented a narrow range (1.8-2.7); however, significant differences (p < 0.05) were found for Al, Cu, Zn, and As among the tree species. Moreover, deciduous Platanus orientalis bioaccumulated more nonessential As than the other species and deserved further risk management. In addition, bark samples from Cinnamomum camphora bioaccumulated more heavy metals than the other species as a result of its morphological and anatomical characteristics. The distribution patterns of heavy metals in tree tissues showed obvious spatial heterogeneity, as impacted by anthropogenic activities to varying degrees. This study examined the biomonitoring potential of roadside trees and the distribution pattern of heavy metals in an urban area under rapid development. Results from the present study could provide baseline data for urban environmental impact assessment and the design of green belts.

Indoor and Outdoor PM10-Bound PAHs in an Urban Environment. Similarity of Mixtures and Source Attribution

Given that the European Union lays down air quality objectives associated with outdoor environments, indoor air mixtures' study acquires a remarkable relevance. This work aims to submit a stepwise methodological framework for assessing similarities between indoor and outdoor air mixtures and apportioning potential emission sources. For reaching this goal, PM₁₀ particles were systematically and simultaneously collected at an indoor (dominant emission sources free) and outdoor environment during a year to determine the PAH content in both air mixtures. Broadly, outdoor PAHs levels were higher than at the indoor location, supporting a strong association between both mixtures (r = 0.968, p > 0.001), mainly during the cold period (r = 0.896, p > 0.001). The light molecular weight PAHs were highlighted at the indoor site, in particular to naphthalene and anthracene. Outdoor emission sources influenced the indoor PAH levels, especially high and medium molecular weight PAHs. The local-traffic load was identified as a dominant pollution source responsible for more than half PAHs determined at both environments. Therefore, the control of outdoor emission sources would be translated into an improvement of indoor air quality.

Study on Pollution Characterization and Source Apportionment of Daytime and Nighttime PM2.5 Samples in an Urban Residential Community in Different Weather Conditions

Daytime and nighttime PM_2.5 samples were collected from an urban community in Tianjin. The major chemical components in PM_2.5, including metal elements, polycyclic aromatic hydrocarbons and inorganic water-soluble ions, were monitored. A positive matrix factorization (PMF) model was used to apportion the potential sources of PM_2.5 under different weather conditions. When the Air Quality Index (AQI) was below 200, the concentrations of BaA, BbF, BkF, Na and NO₃^- during the nighttime were higher than those during the daytime. PMF analysis indicated that secondary aerosols (37.3%), biomass burning (26.7%) and coal combustion (26.0%) were important sources of PM_2.5 in the urban residential community when the AQI was greater than 200. When the AQI was less than 200 in the urban residential community, the main sources of PM_2.5 in the urban residential community were secondary aerosols (50.7%) and fossil fuel combustion (47.2%). The pollution status of PM_2.5 in the residential community of the urban area was serious, and the source apportionments of the PM_2.5 samples in the urban area were different under different weather conditions.

Distribution, sources and health risk of PAHs in urban air-conditioning dust from Hefei, East China

In recent decades, indoor air quality (IAQ) has become one of the most important human health issues. The potential properties and potential health hazards of polycyclic aromatic hydrocarbons (PAHs) are associated with their long-term residues, bioaccumulation and semivolatility, and they can also be transferred through a variety of media, such as the atmosphere, water and soil. Dust particles from indoor and outdoor emission sources adhere to A-C filters and can represent air quality to a certain extent. However, few studies have focused on PAHs in A-C filter dust in Hefei, China. In this study, 16 PAHs were selected, dust samples were collected from A-C filters from three different functional districts, and GC-MS analysis of the samples was performed. The concentration of the ∑16PAHs ranged from 7.34 to 326.84 μg g^-1, 5.07-15.34 μg g^-1, 4.09-47.26 μg g^-1 and 0.97-13.38 μg g^-1 in dust samples from the Administrative District (AD), Industrial District (ID), Commercial District (CD) and Outdoors (OD), respectively. The total PAH concentration in A-C dust was much higher than that in dust deposited outdoors in the urban area. The percentage of 5-6 ring PAHs accounted for more than 70% of the ∑16PAHs, which shows that the PAHs in A-C dust mainly come from pyrolysis rather than a diagenetic source. Principal component analysis (PCA) and diagnostic ratios were used in a source analysis, and the results indicated that the main PAHs emission sources in the different functional districts were coal, wood and biomass combustion. The incremental lifetime cancer risk (ILCR) values indicated a medium to high potential carcinogenic risk for adults and children exposed to dust with PAHs. Particularly, skin contact and ingestion of carcinogenic PAHs from dust are the major exposure pathways and present an exposure risk that is four to five orders of magnitude higher than the risk of inhalation.

The Characteristics of Polycyclic Aromatic Hydrocarbons in Different Emission Source Areas in Shenyang, China

Particulate matter (PM) was collected in three different areas, SY-1, SY-2, and SY-3, in Shenyang, China, during the warm and cold seasons from 2012 to 2014. SY-1 was located beside a thermal power plant, far from the central area. SY-2 was near a coal heating boiler on the main road, close to the central area. SY-3 was on the main road, without fixed emission sources. Nine PM-bound polycyclic aromatic hydrocarbons (PAHs) were analyzed. The results showed that the mean concentration of total PAHs was higher in the cold season (92.6-316 ng m-3) than in the warm season (18.4-32.2 ng m-3). Five- and six-ring PAHs occupied a large percentage at all sites in the warm season, and four-ring PAHs were the dominant components in the cold season. Several diagnostic PAH ratios indicated that the main sources of PAHs in Shenyang in the warm and cold seasons were not only coal burning but also vehicle emission. In this study, we suggest that a benzo[a]pyrene/benzo[ghi]perylene ratio ([BaP]/[BgPe]) of 0.6 was a useful indicator to speculate the relative significance of coal burning and vehicle exhaust. Although the Shenyang government has undertaken actions to address air pollution, the PM and PAH concentrations did not decrease significantly compared to those in our previous studies. The cancer risk calculated from the BaP equivalent total concentration at all three sites in the warm and cold seasons exceeded the acceptable limit established by the US EPA.

Polycyclic aromatic hydrocarbon (PAHs) geographical distribution in China and their source, risk assessment analysis

In China, the huge amounts of energy consumption caused severe carcinogenic polycyclic aromatic hydrocarbon (PAHs) concentration in the soil and ambient air. This paper summarized that the references published in 2008-2018 and suggested that biomass, coal and vehicular emissions were categorized as major sources of PAHs in China. In 2016, the emitted PAHs in China due to the incomplete combustion of fuel was about 32720 tonnes, and the contribution of the emission sources was the sequence: biomass combustion > residential coal combustion > vehicle > coke production > refine oil > power plant > natural gas combustion. The total amount of PAHs emission in China at 2016 was significantly decreased due to the decrease of the proportion of crop resides burning (indoor and open burning). The geographical distribution of PAHs concentration demonstrated that PAHs concentration in the urban soil is 0.092-4.733 μg/g. At 2008-2012, the serious PAHs concentration in the urban soil occurred in the eastern China, which was shifted to western China after 2012. The concentration of particulate and gaseous PAHs in China is 1-151 ng/m3 and 1.08-217 ng/m3, respectively. The concentration of particle-bound PAHs in the southwest and eastern region are lower than that in north and central region of China. The incremental lifetime cancer risk (ILCR) analysis demonstrates that ILCR in the soil and ambient air in China is below the acceptable cancer risk level of 10-6 recommended by US Environmental Protection Agency (EPA), which mean that there is a low potential PAHs carcinogenic risk for the soil and ambient air in China.

Pollution Characterization and Source Apportionment of Day and Night PM2.5 Samples in Urban and Suburban Communities of Tianjin (China)

Day and night PM_2.5 samples were collected from two typical urban and suburban communities in Tianjin. The major chemical components in PM_2.5, including the metal elements, polycyclic aromatic hydrocarbons (PAHs), and inorganic water-soluble ions, were monitored. A positive matrix factorization (PMF) model was used to apportion the potential sources of PM_2.5 at the two sites in the daytime and nighttime. The results indicated that the PM_2.5 concentration was higher in the suburban area than in the urban area during the daytime in winter. The daytime and nighttime PAHs concentrations at both sites were both generally higher in winter than in summer. The concentrations of some of the metal elements were higher in summer than in winter. Regional differences and day and night differences in the metals and water-soluble ions commonly existed. The PMF analysis indicated that coal combustion and transportation-related sources were the predominant sources in the urban and suburban areas in the daytime in winter, and secondary aerosols were the most important source for the suburban area in the nighttime in winter. There were more pollution sources of PM_2.5 during the daytime in summer, especially in the suburban area. In the nighttime in summer, the pollution sources of PM_2.5 in the urban and suburbs areas were basically the same, but the source apportionment was quite different.

An overview of research and development themes in the measurement and occurrences of polyaromatic hydrocarbons in dusts and particulates

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds consisting of two or more fused aromatic rings and are probably one of the most studied groups of organic chemicals in environmental research. PAHs originate mainly from anthropogenic processes, particularly from incomplete combustion of organic fuels. PAHs are distributed widely in particulate matter. Due to widespread sources and persistent characteristics, PAHs disperse through atmospheric transport and exist almost everywhere. Human beings are exposed to PAH mixtures in gaseous or particulate phases in ambient air. Long-term exposure to high concentrations of PAHs is associated with adverse health problems. This review identifies the main research and development themes in the measurement and occurrences of PAHs in dusts and particulates using a new approach to carrying out a literature review where many peer-review publications have been produced. The review extracts the most important research themes from a literature search using a combination of text mining and a more detailed review of selected papers from within the identified themes.

Levels, characteristics and health risk assessment of VOCs in different functional zones of Hefei

In order to study the characteristics and health risk of VOCs in the ambient air in the typical developing cities in China, the research was conducted in five functional zones in Hefei from September 2016 to January 2017. The average concentrations of total measured VOCs in traffic zone was the largest (85.94 μg m^-3), followed by industrial zone (64.84 μg m^-3), development zone (58.92 μg m^-3), resident zone (57.31 μg m^-3), and background zone (54.94 μg m^-3). Cl-VOCs were most abundant species in chlorinated VOCs (85.06%), which showed much higher level in industrial zone. the mean value of BTEX found in presented study was 65.19 μg m^-3. Based on the specific VOC ratio method (B/T), the observed sites were greatly affected by the traffic emissions. The ratios of T/B, E/B and X/B were 1.15, 1.35 and 0.47, respectively, possibly due to the aging air mass. Carcinogenic risks for benzene, carbon tetrachloride, trichloroethylene, 1, 2-dichloroethane and chloroform were higher than the general acceptable risk level of 1.00 × 10^-6. Potential non-carcinogenic risk assessment showed that hazard quotient (HQ) of 10 VOCs not exceeded unity, but the hazard risk index (HI) at site ED, LY, YH and HD were both higher than 1.

Association between cancer risk and polycyclic aromatic hydrocarbons' exposure in the ambient air of Ahvaz, southwest of Iran

Nowadays, a large number of health endpoints such as disease rates, treatment costs, and death, by air pollutants, have been a serious health problem for humans. One of the most hazardous air pollutants, which is highly dangerous for human health, is polycyclic aromatic hydrocarbons (PAHs). The existence of the emission of industries' pollutants and seasonal variations are the primary agents affecting PAHs' concentration. The purposes of this study were to calculate the cancer risk and measure PAHs' exposure in the ambient air of Ahvaz, southwest of Iran, during 2017. Three distinct areas ((S1) industrial, (S2) high traffic, and (S3) residential) of Ahvaz metropolitan were selected. Omni sampler equipped with polytetrafluoroethylene (PTFE) filters were used for active sampling of PAHs. To detect the level of PAHs, gas chromatography with mass spectrometry (GC/MS) was used. Incremental lifetime cancer risk (ILCR) and lifetime average daily dose (LADD) were used to estimate the health risk caused by PAHs. The results showed that the residential and industrial areas had the lowest and highest level of PAHs. Moreover, the average levels of PAHs in industrial, high traffic, and residential areas were 8.44 ± 3.37, 7.11 ± 2.64, and 5.52 ± 1.63 ng m^-3, respectively. Furthermore, ILCR in autumn and winter was higher than EPA standard, 0.06307 and 0.04718, respectively. In addition, ILCR in different areas was significantly higher than standard. Research findings imply that the levels of exposure to PAHs can increase ILCR and risk of health endpoint. The cancer risk attributed to PAHs should be further investigated from the perspective of the public health in metropolitans.

Health risk assessment on human exposed to heavy metals in the ambient air PM10 in Ahvaz, southwest Iran

Heavy metals (HM) are one of the main components of urban air pollution. Today, megacities and industrial regions in southwest of Iran are frequently suffering from severe haze episodes, which essentially caused by PM₁₀-bound heavy metals. The purpose of this study was to evaluate the health risk assessment on human exposed to heavy metals (Cr, Ni, Pb, and Zn) in the ambient air PM₁₀ in Ahvaz, southwest Iran. In this study, we estimated healthy people from the following scenarios: (S3) residential site; (S2) high-traffic site; (S1) industrial site in Ahvaz metropolitan during autumn and winter. In the current study, high-volume air samplers equipped with quartz fiber filters were used to sampling and measurements of heavy metal concentration. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was utilized for detection of heavy metal concentration (ng m^-3). Also, an estimate of the amount of health risk assessment (hazard index) of Cr, Ni, Pb, and Zn of heavy metal exposure to participants was used. Result of this study showed that the residential and industrial areas had the lowest and the highest level of heavy metal. Based on the result of this study, average levels of heavy metal in industrial, high-traffic, and residential areas in autumn and winter were 31.48, 30.89, and 23.21 μg m^-3 and 42.60, 37.70, and 40.07 μg m^-3, respectively. Based on the result of this study, the highest and the lowest concentration of heavy metal had in the industrial and residential areas. Zn and Pb were the most abundant elements among the studied PM₁₀-bound heavy metals, followed by Cr and Ni. The carcinogenic risks of Cr, Pb, and the integral HQ of metals in PM₁₀ for children and adults via inhalation and dermal exposures exceeded 1 × 10^-4 in three areas. Also, based on the result of this study, the values of hazard index (HI) of HM exposure in different areas were significantly higher than standard. The health risks attributed to HM should be further investigated from the perspective of the public health in metropolitans. The result of this study showed increasing exposure concentrations to heavy metal in the studied scenarios have a significant potential for generating different health endpoints, while environmental health management in ambient air can cause disorders in citizenship and causing more spiritual and material costs.

Particle-Associated Polycyclic Aromatic Hydrocarbons (PAHs) in the Atmosphere of Hefei, China: Levels, Characterizations and Health Risks

Airborne PM2.5 and PM10 samples were collected in summertime (August 2015) and wintertime (December 2015-January 2016) in an industrial complex area in Hefei, China. The average concentrations of PM2.5 and PM10 (90.5 and 114.5 μg/m³, respectively) were higher than the regulated levels of China National Ambient Air Quality Standard (grade I) and the WHO Ambient (outdoor) Air Quality and Health Guideline Value. Seasonal variations in PM2.5/PM10 indicated that the secondary sources of particulate matters, formed by gas-to-particle conversion, were enhanced in summer due to longer time of solar radiation and higher temperature. The total concentrations of PM2.5- and PM10-associated PAHs were 5.89 and 17.70 ng/m³ in summer as well as 63.41 and 78.26 ng/m³ in winter, respectively. Both PM2.5- and PM10-associated PAHs were dominated by 4- to 6-ring PAHs, suggesting that the fossil fuel combustion and vehicle emissions were the primary sources of PAHs in atmospheric particulate matters in Hefei. The total concentration of PAHs had a slightly higher correlation coefficient with PM2.5 (R = 0.499, P < 0.05) than PM10 (R = 0.431, P > 0.05), indicating the higher association tendency of PAHs with PM2.5. The coefficient of divergence analysis showed that the compositions of PAH were quite different between summer and winter. Total BaP equivalent concentration (BaP-TEQ) for particulate-bound PAHs in winter (58.87 ng/m³) was higher than that in summer (5.53 ng/m³). In addition, particulate-bound PAHs in winter had an inhalation cancer risk (ICR) value of 2.8 × 10^-3, which was higher than the safe range (10^-4-10^-6).