Average Polycyclic Aromatic Hydrocarbons Concentrations Research Articles

Characteristics of Black Carbon Particle-Bound Polycyclic Aromatic Hydrocarbons in Two Sites of Nanjing and Shanghai, China

Airborne polycyclic aromatic hydrocarbons (PAHs) are of great concern to human health due to their potential high toxicity. Understanding the characteristics and sources of PAHs, as well as the governing factors, is therefore critical. PAHs and refractory black carbon (rBC) are both from combustion sources. This work, for the first time, investigated exclusively the rBC-bound PAH properties by using a laser-only Aerodyne soot-particle aerosol mass spectrometer (SP-AMS). This technique offers highly time-resolved PAH results that a traditional offline measurement is unable to provide. We analyzed two datasets conducted in urban Shanghai during the fall of 2018 and in suburban Nanjing during the winter of 2017, respectively. Results show that the average concentration of PAHs in Nanjing was much higher than that in Shanghai. Nanjing PAHs contained more low molecular weight components while Shanghai PAHs contained more high molecular weight ones. PAHs in Shanghai presented two peaks in early morning and evening, while Nanjing PAHs had only one significant morning peak, but remained high throughout the nighttime. A multi-linear regression algorithm combined with positive matrix factorization (PMF) analyses on sources of PAHs reveals that the industry emissions contributed the majority of PAHs in Nanjing (~80%), while traffic emissions dominated PAHs in Shanghai (~70%). We further investigated the relationships between PAHs with various factors. PAHs in both sites tended to positively correlate with primary pollutants, including primary organic aerosol (OA) factors, and gaseous pollutants of CO, NO2 and SO2, but negatively correlated with secondary OA factors and O3. This result highlights the enhancement of rBC-bound PAHs level due to primary emissions and their oxidation loss upon atmospheric aging reactions. High concentration of PAHs seemed to frequently appear under low temperature and high relative humidity conditions, especially in Shanghai.

Polycyclic Aromatic Hydrocarbon Gaseous Emissions from Household Cooking Devices: A Kenyan Case Study.

In developing countries, household energy use is highly variable and complex, yet emissions arising from fuel combustion indoors are typically poorly quantified. Polycyclic aromatic hydrocarbons (PAHs) are emitted during the combustion of organic fuels such as charcoal and biomass. In the present study, multichannel polydimethylsiloxane rubber traps were used for gas-phase PAH sampling and extracted using a low-solvent volume plunger-assisted solvent extraction method. Sixteen US Environmental Protection Agency priority PAHs, primarily in the gas phase, were investigated in indoor air of rural and urban residential homes in coastal Kenya (Mombasa and Taita Taveta Counties) using typical combustion devices of each area. Average gaseous PAH concentrations per household were higher in rural (ranging 0.81-6.09 µg m-3 ) compared to urban (ranging 0-2.59 µg m-3 ) homes, although ambient PAH concentrations were higher in urban environments, likely attributable to traffic contributions. The impact of fuel choice and thereby combustion device on PAH emissions was very clear, with the highest concentrations of PAHs quantified from wood-burning emissions from 3-stone stoves (total PAH averages 46.23 ± 3.24 µg m-3 [n = 6]). Average benzo[a]pyrene equivalent total concentrations were evaluated for the priority PAHs and ranged from not detected to 43.31, 88.38, 309.61, and 453.88 ng m-3 for gas, kerosene, jiko, 3-stone, and improved 3-stone stoves, respectively. Environ Toxicol Chem 2020;39:538-547. © 2019 SETAC.

Health risk assessment of polycyclic aromatic hydrocarbons in coastal soils of Koh Samed Island (Thailand) after the oil spill incident in 2013

Health risks of human exposures to 12 Polycyclic aromatic hydrocarbons (PAHs) in coastal soils of Koh Samed Island (KSI), Thailand, were evaluated after the coastal areas were cleaned up of the 2013 oil-spill contamination. The risk assessment quantified both total cancer and non-cancer risks for four groups of receptors using average PAHs concentrations. Two exposure pathways (incidental ingestion and dermal contact) were selected to evaluate the risks, and three methods were used to calculate the total cancer risks to determine an appropriate assessment method. The non-cancer risk was represented by the total Hazard Index (HI). The contributions of each PAH to the total cancer risk and total HI were also investigated. The total cancer risk (3.53×10−10 to 9.12×10−8) and total HI (4.35×10−6 to 2.13×10−3) from this work were relatively lower than the USEPA baselines (10-6 for the cancer risk and 1 for the HI) and were quite low when compared with other works in the literature. Benzo(a)pyrene made the highest contribution to the total cancer risk (61.82%), while benzo[g,h,i]perylene made the highest contribution to the total HI (62.41%). In regard to the contributions of the two exposure routes, dermal contact contributed the most to the total cancer risk, while incidental ingestion contributed the most to the total HI.

High cancer risk from inhalation exposure to PAHs in Fenhe Plain in winter: A particulate size distribution-based study

Fenhe Plain is a typical region polluted combinedly by coal combustion and coking activities with serious air pollution problem, especially in winter. In order to clarify the size distribution and health risk of polycyclic aromatic hydrocarbons (PAHs) in winter of the Fenhe Plain, the respirable aerosol particles (PM10) were collected by cascade impactor, and 17 PAHs were analyzed. The results showed that the average mass concentration of PM10-bound PAHs was 689.19 ng/m3, which was higher than that in many other domestic and overseas cities. The particulate PAHs mainly distributed in the <0.95 μm size range, accounting for more than 60% of the total. Under the combined influence of local emissions, low temperature, low intensity of solar radiation, dry atmosphere and Kelvin effect, naphthalene (Nap) displayed a bimodal distribution, while the rest of the 17 PAHs all followed a nearly unimodal size distribution. Wind and humidity were important factors which could influence the size distribution of PAHs. Coefficient of divergence (CD) analysis showed that PAHs between all of the sizes had a high spatial heterogeneity in source factor contributions, although diagnostic ratio indicated similar sources among them. Health risk assessment found that the lifetime cancer risk of exposure to particulate PAHs was 1693.76 parts per million people. Ultrafine particles (<0.95 μm) predominated the total carcinogenicity of the particulate PAHs, while benzo(a)pyrene (BaP), dibenzo(a,h)anthracene (DahA), benzo(b)fluoranthene (BbF), benzo(a)anthracene (BaA), benzo(k)fluoranthene (BkF) and indeno(1,2,3-cd)pyrene (IcdP) were the major carcinogenic components. Traffic exhausts contributed most to the carcinogenic PAHs, followed by coal combustion and coking. Our study can provide reference for the pollution control and residential health protection in Fenhe Plain, and bring more reasonable parameterizations to the estimation of PAHs outflow from this key region to other international regions.

Occurrence of polycyclic aromatic hydrocarbons (PAHs) in air and soil surrounding a coal-fired thermal power plant in the south-west coast of India.

This investigation focused on the potential sources of polycyclic aromatic hydrocarbons (PAHs) in different matrices and their temporal variations surrounding a coal-fired thermal power plant in India. Samples were collected in different seasons for 1year. Gas chromatography-mass spectroscopy (GC-MS) was used to perform the measurement of 16 priority PAHs. Average PAH concentrations were ranged from 0.71 to 2.99ng/m3 in air and 1.59-22.7ng/g in soil respectively. High levels of PAHs were found in soil compared to air, which indicated deposition in soil. This could be because of the fallout of high-molecular-weight compounds. During the monsoons, PAH concentrations in the air were the lowest compared to the other seasons because of the dilution effect. Phenanthrene, fluoranthene, and pyrenes were dominant in the air, contributing up to 32.5%, 22.7%, and 19.2% of total PAHs, respectively. On the other hand, soils contained fluoranthene (12.3%), pyrene (10.7%), benzo[b]fluoranthene (10%), chrysene (9.82%), and indeno[123-c,d]pyrene (9.64%) compounds. The occurrence of indeno[1,2,3-cd]pyrene (9.14ng/g) indicated that the soil is contaminated from fly ash and diesel emissions from the thermal power plant and vehicular emission. The diagnostic ratios, thematic maps, and principal component analysis revealed that the fly ash, diesel emissions from the thermal power plant, vehicles, and biomass burning were the probable sources of PAHs in the study area. The human health risk assessment studies reveal that the soil samples are more prone to carcinogenicity than air samples. As per our knowledge, this is the first report on the impact of PAHs on air and soil in this region.

Preliminary Assessment of the Distribution of PM2.5-Bound Polycyclic Aromatic Hydrocarbons in Primary School Environments in Kuala Lumpur

Fine particulate matter (aerodynamic diameter ≤2.5 µm) (PM2.5) has become a major concern because it can adsorb chemicals e.g. polycyclic aromatic hydrocarbons (PAHs) onto its surface. Although PAHs are priority pollutants that can cause adverse health effect, there is still limited information concerning indoor exposures to PAHs in Malaysia. This study aimed to characterise the distribution of PAHs bounded to PM2.5 in primary school environments. Indoor and outdoor PM2.5 were collected between May and July 2017 using low volume samplers (LVS) at three public primary schools in the Federal Territory of Kuala Lumpur. PAHs were extracted by ultrasonic extraction with Dichloromethane:n-Hexane (1:1, v/v) as the extraction solvent and analysed using gas chromatography coupled with mass spectrometer (GC-MS). Based on the results, the average total concentration of PAHs (∑PAHs) ranged from 3.8 to 10.1 ng m-3 and 1.6 to 8.0 ng m-3 for outdoors and indoors, respectively. PAHs in PM2.5 samples indicated the potential contribution of combustion at high temperature and indoor sources, and the infiltration of outdoor PAHs were the important sources for outdoor and indoor, respectively. In addition, the diagnostic ratio analysis showed that vehicular emissions were the most predominant sources of PAHs in school environments.

Potential Risk Assessment of Selected Polycyclic Aromatic Hydrocarbons in Vegetables Grown in Polluted and Non-polluted Areas of Sindh, Pakistan

Polycyclic Aromatic Hydrocarbons (PAHs) were determined in vegetables grown in Sindh, Pakistan. The vegetables were collected from both local markets and industrial areas where vegetation was carried out. All three types of vegetables, root vegetables, leafy vegetables and fruit vegetables were selected for analysis. The PAHs were extracted by Soxhlet extraction method and analysed by gas chromatography. The results showed that average concentration of PAHs in vegetables was ranged from 1.62±0.01 µg/kg to 144.52±2.51 µg/kg. From seven PAHs analyzed, the fluorene was found to be present in almost all vegetable samples and was highest in bitter guard that is 144.52±2.51 µg/kg. Like fluorene, naphthalene and anthracene were also present in all the vegetables but their concentration was not very high (6.89±0.03 µg/kg for naphthalene and 2.18±0.01 for anthracene). Higher concentration of PAHs was observed in samples collected from industrial areas due to the fact that industrial smoke could easily be absorbed by the vegetables grown in those areas.

Seasonal variation, air-water exchange, and multivariate source apportionment of polycyclic aromatic hydrocarbons in the coastal area of Dalian, China

The concentrations and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) in air and seawater dissolved samples from the coastal area of Dalian were investigated, as well as their air-water exchanges. The average concentrations of PAHs were 27.5 ± 14.6 ng/m3 and 49.5 ± 20.5 ng/L in the air and water, respectively. Phenanthrene was the dominant congener in both air and water dissolved phase. Seasonality was discovered in the air with the concentrations higher in winter than in summer, but not in the water dissolved phase. Air-water exchange trends also displayed apparent seasonality with 3–4 ring PAHs generally being volatilization or equilibrium in summer but deposition in winter, which highlighted the important influence of temperature on the air-water exchange direction of PAHs. The air-water exchange fluxes of individual PAH congeners ranged from −24331 to 6541 ng/m2/d, and the highest deposition and volatilization fluxes both appeared at the industrial areas, which emphasized the influence of point source emission to the magnitude of air-water diffusion flux of PAHs. Multivariate source apportionment approaches, including principle component analysis, diagnostic ratios, and positive matrix factorization, were conducted, which suggested that PAHs in water originated from multiple sources. Frequent port transport correlated vehicle/ship emission rather than coal combustion may be the primary contributor of PAHs to the coastal air and water.

Measurements of 50 Non-polar Organic Compounds Including Polycyclic Aromatic Hydrocarbons, n-Alkanes and Phthalate Esters in Fine Particulate Matter (PM2.5) in an Industrial Area of Chiba Prefecture, Japan

Quantitative data of 50 non-polar organic compounds constituting PM2.5 were continuously collected and analyzed from June 2016 to October 2017 (approximately 17 months) at Ichihara, one of the largest industrial areas in Japan. Target non-polar organic compounds including 21 species of polycyclic aromatic hydrocarbons (PAHs), 24 species of n-alkanes and 5 species of phthalate esters (PAEs) were simultaneously measured by gas chromatography/mass spectrometry. Basically, the average concentrations of the total PAHs, n-alkanes and PAEs in each season remained nearly level, and seasonal variations were little throughout the study period. These results suggest that the emission sources, which are not influenced by the seasons, are the dominant inputs for the target organic compounds. Diagnostic ratios of PAHs, assessment of n-alkane homologue distributions, carbon preference index, and the contribution of wax n-alkanes from plants were used to estimate source apportionments. These results indicate that anthropogenic sources were the main contributor for most PAHs and n-alkanes throughout the study period. The concentrations of PAEs selected in this study were low because emission amounts of these chemicals were little within the source areas of the sampling site. To our knowledge, this study is the first attempt to simultaneously measure a high number of non-polar organic compounds in PM2.5 collected from the ambient air of Japan, and the resultant data will provide valuable data and information for environmental researchers.

Bioaccumulation and Cycling of Polycyclic Aromatic Hydrocarbons (PAHs) in Typical Mangrove Wetlands of Hainan Island, South China.

Mangrove wetlands are important coastal ecosystems in tropical and subtropical regions, and mangrove sediments and tissues often are the pollutant sinks due to their high organic matter contents. Polycyclic aromatic hydrocarbons (PAHs) in the mangrove sediments and tissues of nine species from three typical mangrove wetlands of Hainan Island were studied. The average concentration of PAHs in all mangrove tissues was 403ngg-1dw, with PAHs concentrations in leaf, branch, root, and fruit of 566, 335, 314, and 353ngg-1dw, respectively. PAHs levels were much higher in leaf than in other mangrove tissues, which may be caused partly by atmospheric deposition of PAHs. The dominant individual PAH compounds in mangrove tissues were phenanthrene (41.3%), fluoranthene (14.7%), and pyrene (11.4%), while in sediments were naphthalene (73.4%), phenanthrene (3.9%), and pyrene (3.6%), respectively. The biota-sediment accumulation factors of PAH congeners in the mangrove wetlands showed different patterns, with the most predominant of phenanthrene. The cycling of PAHs in the mangrove wetlands of Hainan Island also were estimated, and the results showed that the standing accumulation, the annual absorption, the annual net retention, the annual return, and the turnover period in all mangrove tissues of the community were 2228µgm-2, 869µgm-2a-1, 206µgm-2a-1, 663µgm-2a-1, and 3.4a, respectively. These results indicated that mangroves are playing an important role in retaining PAHs.

Discussion of Emissions and Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) from the Retreading Process of Waste Tires

The emissions characteristics of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in ambient air during the waste tire retreading process (open-air storage, mixing, vulcanization, and grinding processes) and in workers' dormitory were analyzed. In addition, the occupational health risk of the workers was evaluated. Results showed that PAHs were detected in all retreading processes and in the workers' dormitory. The highest concentration site was the mixing process, followed by open-air storage and vulcanization process. The lowest concentration point was in the grinding process. The average concentration of PAHs in the workers' dormitory was 11.1 ng·m-3. The PAHs at all sampling points were largely phenanthrene (Phe), fluoranthene (Flu), anthracene (Ant), and pyrene (Pry), which also had a stronger linear correlation with the total PAH concentration. An analysis of the benzene rings showed that three ring and four ring were the majority, while two ring, five ring, and six ring components accounted for less than 10%. Results of the possible influencing factors of the PAHs revealed that the open-air storage and dormitory might be affected by a combustion source, but the mixing, vulcanization, and grinding processes might be affected by rubber oil. The principal component analysis (PCA) and cluster analysis showed that the spatial location of all sites would significantly influence the distribution of PAHs during the tire retreading process. The health risk assessment showed that occupational workers had a lower risk of lifelong cancer, and there was little influence on life expectancy.

Source Apportionment and Risk Assessment of Atmospheric Polycyclic Aromatic Hydrocarbons in Lhasa, Tibet, China

Much attention has been given to the distributions, sources, and health risks of atmospheric polycyclic aromatic hydrocarbons (PAHs) in cities. In this study, a total of 62 suspended particle samples were collected from April 2013 till March 2014 in the city of Lhasa. Positive matrix factorization (PMF) was applied to investigate the source apportionment of 15 priority PAHs, the lifetime carcinogenic risk (LCR) levels of which were assessed. The average annual particle phase PAH concentration was 43.9 ± 60.4 ng m–3. Evident seasonal variations of PAHs were observed, with the highest concentration observed in winter, followed by autumn, spring, and summer. Four- and five-ring PAHs accounted for the predominant proportion (63.3%–84.4%) throughout the year. Correspondingly, gas phase PAHs showed the opposite variations, with the highest and lowest concentrations observed in summer and winter, respectively; also, three-ring PAHs, especially Ace, Acel, and Flu, were the largest contributors. Compositions of particle phase PAHs varied seasonally, with four-ring PAHs contributing more in winter than in summer and five-ring PAHs exhibiting the opposite trend, thereby reflecting the variety of emission sources. PMF analysis showed that biomass combustion (48.4%) and vehicle emissions (27.9%) were the two main sources, followed by coal combustion and the air–surface exchange. These results were consistent with the diagnostic molecular ratios. The benzo(a)pyrene equivalent (BaPeq) concentration of particle phase PAHs ranged from 1.48 to 24.5 ng m–3, which exceeds were higher than the new limit in China (1 ng m–3). The average BaPeq of gas phase PAHs was 6.43 ± 4.15 ng m–3, which was similar to that of particle phase PAHs. The LCR of the total PAHs (9.08 × 10–6) was one time higher than that of the particle phase; however, it was slightly lower than the acceptable level, thereby indicating that atmospheric PAHs in Lhasa pose little or no carcinogenic risk to the local population.

Long-term trends of atmospheric organochlorine pollutants and polycyclic aromatic hydrocarbons over the southeastern Tibetan Plateau

Long-term monitoring in remote regions is essential for revealing pollution trends at the global scale but relevant studies remain limited. In the present study, a six-year continuous monitoring of atmospheric persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) was carried out at Lulang in the southeastern Tibetan Plateau (TP). Average concentrations of hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), polychlorinated biphenyls (PCBs) and PAHs were 13.5, 8.9, 41.7, 1.8pg/m3 and 6.2ng/m3, respectively. Obvious seasonality was found for all the target compounds. HCHs, DDTs and PCBs had their highest concentrations in summer (monsoon season) and lowest in winter, which is consistent with the fluctuation of the Indian monsoon. Meanwhile, HCB and 5–6-ring PAHs showed opposite variations, possibly induced by local sources and the westerly flow in winter. Declining trends were observed for most of the chemicals, except o,p′-DDE, HCB and PCBs. A declining trend in the α/γ-HCH ratio indicated a shift from technical HCHs to lindane. An increasing trend in the o,p′/p,p′-DDT ratio suggested a likely shift from technical DDTs to dicofol. For PAHs, the contribution from high-temperature combustion has increased recently. The half-lives of α-HCH, γ-HCH, o,p′-DDT, p,p′-DDT were 6.1, 108, 77.6 and 14.2years, respectively. The half-lives of γ-HCH, o,p′-DDT and p,p′-DDT were higher than those in the Arctic, indicating these compounds will persist in the TP for a longer period. The temporal trends in atmospheric POPs were possibly induced by emissions in India and likely driven by wind speed in Lulang. This study contributes toward a better understanding of the behavior and transport of POPs in the TP region.

Polycyclic aromatic hydrocarbons in indoor and outdoor air in Turkey: Estimations of sources and exposure

ABSTRACTThe aim of the current study was to measure polycyclic aromatic hydrocarbons (PAHs) in eight indoor (In both kitchen and living room) air sampling locations using a passive sampling method for collection. Passive outdoor air samples were also collected from 3 of the same sampling locations as the indoor air sampling sites. Sampling was conducted in three seasons. The summer season, when windows are generally open, was between 18th July and 01st September, 2014; the autumn and winter seasons, when windows are mostly closed, was between 18th October and 01st December, 2014, and 01st December, 2014, and 18th January, 2015, respectively.Average PAH concentrations in summer were 22 ± 21 ng/m3 and 17 ± 12 ng/m3 in the living room and kitchen, respectively, whereas living room and kitchen average PAH concentrations were 23 ± 16 ng/m3 and 20 ± 9 ng/m3, respectively, in autumn and 23 ± 13 ng/m3 and 23 ± 24 ng/m3, respectively, in winter. Outdoor air PAH concentrations in summer, autumn and winter were 7 ± 0.4 ng/m3, 22 ± 13 ng/m3 and 209 ± 33 ng/m3, respectively. An increase in outdoor PAH concentrations was measured in winter compared to the concentrations in summer and autumn, which paralleled the lower outdoor air temperature. However, PAH concentrations in the indoor environment vary according to the household characteristics and personal habits.

Source identification and ecological impact evaluation of PAHs in urban river sediments: A case study in Taiwan

The Love River and Ho-Jin River, two major urban rivers in Kaohsiung City, Taiwan, are moderately to heavily polluted because different types of improperly treated wastewaters are discharged into the rivers. In this study, sediment and river water samples were collected from two rivers to investigate the river water quality and accumulation of polycyclic aromatic hydrocarbons (PAHs) in sediments. The spatial distribution, composition, and source appointment of PAHs of the sediments were examined. The impacts of PAHs on ecological system were assessed using toxic equivalence quotient (TEQ) of potentially carcinogenic PAHs (TEQcarc) and sediment quality guidelines. The average PAHs concentrations ranged from 2161 ng/g in Love River sediment to 160 ng/g in Ho-Jin River sediment. This could be due to the fact that Love River Basin had much higher population density and pyrolytic activities. High-ring PAHs (4–6 rings) contributed to 59–90% of the total PAHs concentrations. Benzo(a)pyrene (BaP) had the highest toxic equivalence quotient (up to 188 ng TEQ/g). Moreover, the downstream sediments contained higher TEQ of total TPHs than midstream and upstream sediment samples. The PAHs were adsorbed onto the fine particles with high organic content. Results from diagnostic ratio analyses indicate that the PAHs in two urban river sediments might originate from oil/coal combustion, traffic-related emissions, and waste combustion (pyrogenic activities). Future pollution prevention and management should target the various industries, incinerators, and transportation emission in this region to reduce the PAHs pollution.

Spatiotemporal distributions of polycyclic aromatic hydrocarbons close to a typical medical waste incinerator.

Environmental contaminations by polycyclic aromatic hydrocarbons (PAHs) especially from incinerators occur subtly, and PAH contribution from this source is underestimated. However, as environmental PAH concentrations build up, this may be a serious concern around the incinerator vicinity due to the potential consequences of PAHs on ecosystems and human health. Thus, the contribution of selected (12) PAHs from the Obafemi Awolowo University Teaching Hospital medical waste incinerator (or source, HWI_0) was determined by sampling stack gas and ambient air around incinerator vicinity from June 2014 to May 2015. Results showed that the 12 PAH source (HWI_0) concentrations were in the range of NA (for phenanthrene, pyrene, anthracene, benz[e]acephenanthrylene, and indeno[2,1-b]chromene) to 10.9ng/m3 (pyrelene) and generally higher than the receptor points (hospital waste incinerators (HWIs)). The average total PAH concentrations per month at HWI_0 and the receptors-HWI_1, HWI_2, HWI_3, HWI_4 and HWI_5-were 73.0±27.9, 60.4±30.8, 42.5±23.6, 38.7±21.9, 35.0±27.2, and 39.2±22.9ng/m3, respectively. These results and multivariate receptor model analysis indicated high correlations between source PAH contributions and the receptor points. The PAH concentrations in the dry season were higher than the wet season suggesting that hydrological condition affects ambient PAH concentrations. The average PAH concentrations in the HWIs as well as the cumulative exposure concentrations observed throughout the period are of major health concern because PAH concentrations detected are several times higher than both the European Union standard and the WHO guideline level.

Pollution characteristics and health risk assessment of polycyclic aromatic hydrocarbons in atmospheric fine particulates PM&amp;lt;sub&amp;gt;2.5&amp;lt;/sub&amp;gt; in Jinhua City

Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances with teratogenic, carcinogenic and mutagenic properties. They are widely detected in atmospheric fine particulates PM2.5. Measuring the concentrations of PAHs in PM2.5 is helpful to understand their pollution levels, environmental sources and fates, which further provides important information for pollution prevention and ecological risk assessment. As semi-volatile organic chemicals, PAHs could partition between air and atmospheric particulates when they are released into the atmosphere. Most of 16 priority PAHs, especially PAHs with 4–6 aromatic rings, mainly exist in particulates, which are frequently taken as research targets for source analysis. Jinhua city locates in the center of Zhejiang Province, and is an important transportation hub in East China. The city air has been polluted by traffic exhaust and coal combustion. However, the atmospheric PAHs levels, pollution characteristics and risk to human health are still unknown. In this study, 30 PM2.5 samples were collected during Dec. 2013–Jan. 2014 in winter atmosphere in Jinhua City. Then 16 priority PAHs were analyzed by GC-MS/MS. The total average concentration of PAHs is 62.75±27.87 ng m - 3, and benzo( b )fluoranthene (15.13%), pyrene (13.05%), fluoranthene (12.47%) and chrysene (10.62%) have the highest concentrations, accounting for more than 50% percentage of Σ PAHs. The components distribution indicates 4-ring PAHs contribute the largest ratio (43.45%) in PM2.5, followed by 5-ring PAHs (39.78%) and 6-ring PAHs (8.43%). Generally, 4-ring PAHs are characteristic emissions of coal combustion and vehicle exhaust mainly contain 5/6-ring PAHs. T -test shows the contents of 4- and 5/6-ring PAHs have no statistical variance (Sig=0.683), indicating coal combustion and vehicle exhaust have similar contributions to the PAHs in PM2.5. This result was also proved by source apportionment which is carried out by analyzing several feature ratios of specific PAHs. The human health risk from PAHs was further evaluated by lifetime cancer risk (ILCR) assessment models. The ILCR values for inhalation exposure to PAHs were calculated to be 4.29/4.41×10 - 6 for children, 7.98/8.25×10 - 6 for teen-agers, 4.92/5.34×10 - 6 for adults, respectively, indicating a low risk of cancer of PAHs in atmospheric PM2.5 in winter in Jinhua.

Seasonal Trends of Atmospheric PAHs in Five Asian Megacities and Source Detection Using Suitable Biomarkers

The most prevalent pollutant, polycyclic aromatic hydrocarbons (PAHs) is now plenteously distributed in the global atmosphere. We recently quantified 36 polycyclic aromatic hydrocarbons (PAHs) associated with aerosols (particulate matter: PM) in five Asian cities: Tokyo (Japan), Beijing (China), Kolkata (India), Hanoi (Vietnam), and Kuala Lumpur (Malaysia). Average atmospheric PAH concentrations (Σ12 PAHs-ng m^(–3)) increased in the order of Kuala Lumpur (2.99) ≈ Tokyo (3.95) ＜ Hanoi (7.99) ＜＜ Kolkata (63.5) ＜＜ Beijing (142.8). The most abundant PAHs in PM samples in these cities were chrysene, benz[a]anthracene, benzofluoranthenes, benzo[a]pyrene, and benzo[e]pyrene. We used the PAH compositions, especially the relative abundances of alkylated PAHs, and hopanes to determine vehicle exhaust-derived PAHs, and levoglucosan as a tracer for biomass burning, especially from wood combustion. Vehicle exhaust contributed to atmospheric PAHs in all cities, indicated by higher ratios of (C_(30)17α)/total PAHs and MPAHs/PAHs than coal and wood combustion products. Coal combustion contributed also in winter aerosols in Beijing, indicated by higher abundance of β isomers i.e., 17β21β (H)-C30hopane (C_(30)17β) and 17β21β (H)-C_(29)hopane (C_(29)17β) signifying mass use of coal for heating. The ratio of levoglucosan/PAHs was high in Kuala Lumpur and Hanoi, suggesting greater inputs of PAHs from biomass burning there.

Quantitative ecological risk assessment of inhabitants exposed to polycyclic aromatic hydrocarbons in terrestrial soils of King George Island, Antarctica

This study aims to conduct a quantitative ecological risk assessment of human exposure to polycyclic aromatic hydrocarbons (PAHs) in terrestrial soils of King George Island, Antarctica. Generally, the average PAH concentrations detected in King George Terrestrial Soils (KGS) were appreciably lower than those of World Marine Sediments (WMS) and World Terrestrial Soils (WTS), highlighting the fact that Antarctica is one of the most pristine continents in the world. The total concentrations of twelve probably carcinogenic PAHs (ΣPAHs: a sum of Phe, An, Fluo, Pyr, B[a]A, Chry, B[b]F, B[k]F, B[a]P, Ind, D[a,h]A and B[g,h,i]P) were 3.21 ± 1.62 ng g−1, 5749 ± 4576 ng g−1, and 257,496 ± 291,268 ng g−1, for KGS, WMS and WTS, respectively. In spite of the fact that KGS has extremely low ΣPAHs in comparison with others, the percentage contribution of Phe is exceedingly high with the value of 50%. By assuming that incidental ingestion and dermal contact are two major exposure pathways responsible for the adverse human health effects, the cancer and non-cancer risks from environmental exposure to PAHs were carefully evaluated based on the “Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions” memorandum provided by US-EPA. The logarithms of cancer risk levels of PAH contents in KGS varied from −11.1 to −7.18 with an average of −7.96 ± 7.73, which is 1790 times and 80,176 times lower than that of WMS and WTS, respectively. All cancer risk levels of PAH concentrations observed in KGS are significantly (p < 0.001) lower than those of WMS and WTS. Despite the Comandante Ferraz Antarctic Station fire occurred in February 25th, 2012, both the cancer and non-cancer risks of environmental exposure to PAHs were found in “acceptable level”.

Removal of Polycyclic Aromatic Hydrocarbons by Extensive Green Roofs

In this study,four pilot-scale extensive green roof facilities with different substrate compositions were developed. In 8 rainfall events, concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in effluent of these facilities were investigated and compared with effluents of asphalt roofing, the blank control roof and rain water. Average PAHs concentrations in the effluent of these four facilities, asphalt roofing and blank control facilities were 145, 166, 151, 160, 900, 270 ng·L-1, respectively. The PAHs mass concentrations discharged by four simulation facilities were significantly lower than asphalt roofing and blank control roof. From the perspective of the mass loading control, all four simulation facilities could effectively control roof runoff PAHs load with an average load reduction rate of 71.76% compared with the blank control roof. Interception and adsorption by green roof substrates was the main removal way for PAHs. Facilities' PAHs removal efficiency could be improved by increasing the substrate thickness with the same substrate composition. Transforming traditional asphalt roofing into extensive green roof was an effective way to control PAHs emissions from roof runoff.