Particulate Polycyclic Aromatic Hydrocarbons Concentrations Research Articles

Long-term (1993–2018) particulate polycyclic aromatic hydrocarbons (PAHs) concentration trend in the atmosphere of Seoul: Changes in major sources and health effects

This study assessed the long-term concentration trend and profiles of twelve polycyclic aromatic hydrocarbons (PAHs) occurring as airborne particulate matter in Seoul, Republic of Korea (Korea) between 1993 and 2018 to evaluate the human health effect and the effectiveness of air quality management policies. Total PAHs (∑PAHs of 12 compounds), benzo [a]pyrene (BaP), and BaP toxic equivalent (BaPTEQ) concentrations increased from 1993 to 1999 but decreased thereafter. Moreover, the BaP concentration has remained below 1 ng/m3 since 2010–2011. Benzo [b+k]fluoranthene (B [b+k]F) accounted for the largest ∑PAHs fraction (approximately 24%) for the entire period. Based on the PAH profiles, as well as the Principal Component Analysis (PCA) results and diagnostic ratio analysis, vehicular emissions and coal combustion were identified as major sources of the PAHs in Seoul. Additionally, contribution of vehicular emissions increased from 2002 to 2003 to 2018, whereas that of solid fuel combustion decreased in the same period. PAH levels increased 8-fold in winter compared to summer mainly due to increases in local and regional emissions. The implementation of policies to regulate the use of solid fuels and vehicular emissions in Korea effectively reduced Elemental Carbon (EC) and PAH emissions, as demonstrated by CO, EC, and PAHs reductions and a good correlation between EC and PAHs. Moreover, aggressive air quality management policies in China have also contributed to decreasing PAH concentration trend in Seoul. Following the incremental lifetime cancer risk (ILCR) estimations method for 8 different population groups, males in the 0–1 age group was the only group still at potential risk of PAH inhalation in 2018, while other groups have been in the acceptable risk since 2012–2013.

Assessing the potential risks, sources and the relationship between the dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) in the typical semi-enclosed bay, Bohai Bay of China

This study aimed to investigate the spatial and temporal distribution as well as the partitioning behavior of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) during the summer and autumn seasons of 2020. It was found that the average concentration of PAHs in surface seawater was significantly higher in autumn (58.16 ng L−1) than in summer (40.47 ng L−1) due to a large amount of input in autumn and more photodegradation and biodegradation affected by higher temperatures in summer. The spatial distribution indicated that the river had a significant dilution effect on PAHs in summer and became a significant input source in autumn. In addition, a large number of oil and gas development platforms were distributed throughout the Bohai Bay, and the discharge of production and domestic sewage contributed to the PAHs pollution level. As a semi-enclosed bay, the water exchange capacity of Bohai Bay was poor, leading to a greater accumulation of PAHs in the marine environment. The diagnostic ratios and PCA-MLR indicated that petroleum was the most important source of PAHs with a contribution of 45%, followed by fuel combustion (39%) such as coal and oil. Photooxidation in seawater resulted in a reduction of BaP/BeP, indicating that seasonal variations in photooxidation had a significant impact on the composition of PAHs (summer: 1.49, autumn: 2.96). The concentration of particulate PAHs was correlated with the concentration of dissolved PAHs and SPM, and the proportion of 3-rings (43.8%) and 4-rings (49.8%) PAHs was significantly higher on SPM. The distribution coefficients Log Kd and φspm-water showed a trend of increasing and then decreasing as the number of rings increased, with the 4-rings Pyr exhibiting the highest value. According to the ecological risk assessment, the ecological risk of total PAHs was low (RQNCs < 800, RQMECs < 1), but the ecological risk of individual PAHs and the carcinogenicity of high-ring PAHs could not be ignored (＞96.5%). This study is significant for investigating the “sources and sinks” of PAHs in the complex marine environment by analyzing the partitioning behavior of PAHs in different phases.

Estimation of gaseous polycyclic aromatic hydrocarbons (PAHs) and characteristics of atmospheric PAHs at a traffic site in Kanazawa, Japan

Size-fractionated particulate matter (PM2.5 and PM>2.5) was collected at a traffic site in Kanazawa, Japan in a seasonal sampling work in 2020. Nine polycyclic aromatic hydrocarbons (4- to 6-ring PAHs) were determined in fine and coarse particles. The gas/particle partitioning coefficients (Kp) of the PAHs were calculated from the supercooled liquid vapour pressure and octanol-air partitioning coefficient based on the relationships obtained in previous traffic pollution-related studies. Gaseous PAHs were estimated by Kp and the concentrations of PM and particulate PAHs. The concentrations of total PAHs were 32.5, 320.1 and 5646.2 pg/m3 in the PM>2.5, PM2.5 and gas phases, respectively. Significant seasonal trends in PAHs were observed (particle phase: lowest in summer, gas phase: lowest in spring, particle and gas phase: lowest in spring). Compared to 2019, the total PAH concentrations (in particles) decreased in 2020, especially in spring and summer, which might be due to reduced traffic trips during the COVID-19 outbreak. The incremental lifetime cancer risk (ILCR) calculated from the toxic equivalent concentrations relative to benzo[a]pyrene (BaPeq) was lower than the acceptable limit issued by the US Environmental Protection Agency, indicating a low cancer risk in long-term exposure to current PAH levels. It is notable that gaseous PAHs considerably contributed to BaPeq and ILCR (over 50%), which highlighted the significance of gaseous PAH monitoring for public health protection. This low-cost estimation method for gaseous PAHs can be expected to reliably and conveniently obtain PAH concentrations as a surrogate for traditional sampling in the future work.

Characterization of Gaseous and Particulate Phase Polycyclic Aromatic Hydrocarbons Emitted During Preharvest Burning of Sugar Cane in Different Regions of Kwa-Zulu Natal, South Africa.

Biomass burning is a significant anthropogenic source of air pollution, including the preharvest burning of sugar cane. These burn events result in atmospheric emissions, including semivolatile organic compounds, that may have adverse impacts on air quality and human health on a local, regional, and even a global scale. Gaseous and particulate polycyclic aromatic hydrocarbon (PAH) emissions from various sugar cane burn events in the province of Kwa-Zulu Natal in South Africa were simultaneously sampled using a portable denuder sampling technology, consisting of a quartz fiber filter sandwiched between two polydimethylsiloxane multichannel traps. Total gas and particle phase PAH concentrations ranged from 0.05 to 9.85 µg m-3 per individual burn event, and nine PAHs were quantified. Over 85% of all PAHs were found to exist in the gas phase, with smaller two- and three-ring PAHs, primarily naphthalene, 1-methyl naphthalene, and acenaphthylene, being the most dominant and causing the majority of variance between the burn sites. The PAH profiles differed between the different burn events at different sites, emphasizing the significant influence that the crop variety, prevailing weather conditions, and geographical location has on the type and number of pollutants emitted. The potential carcinogenicity of the PAH exposure was estimated based on toxic equivalency factors that showed varying risk potentials per burn event, with the highest value of 5.97 ng m-3 . Environ Toxicol Chem 2023;42:778-792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Gas-PM2.5 partitioning, health risks, and sources of atmospheric PAHs in a northern China city: Impact of domestic heating

The diurnal variation, gas-particle partitioning, health risks, and sources of polycyclic aromatic hydrocarbons (PAHs) were investigated in a northern basin city of China in winter, 2020. The mean concentrations of particulate and gaseous PAHs were 87.90 ng m−3 and 69.65 ng m−3, respectively, and their concentrations were considerably enhanced during the domestic heating period. The relationship between the gas-particle partitioning coefficient of PAHs (KP) and subcooled liquid vapor pressure of PAHs (PL0) indicated organic absorption as the mechanism for this partitioning. However, the dual sorption model confirmed adsorption onto elemental carbon (EC). The health risks indicated by several equivalent parameters showed an important health effect of PAHs, especially of particulate PAHs bound onto PM2.5 during the heating period. Environmentally persistent free radicals (EPFRs) were also studied as an auxiliary parameter to evaluate the health impact of PAHs. According to the diagnostic ratios of PAHs and PMF model results, petroleum volatilization and coal combustion were the dominant sources of particulate PAHs during the non-heating and heating periods, respectively. The source apportionment results can help efficiently control PAHs and their health risks.

Characteristics of Fine Particulate Matter (PM2.5)-Bound n-Alkanes and Polycyclic Aromatic Hydrocarbons (PAHs) in a Hong Kong Suburban Area

PM2.5 samples were collected at Tung Chung (TC), Hong Kong, during four nonconsecutive months in 2011/2012 to determine the concentrations, seasonal variations, and potential sources of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes (n-C15-n-C35). Samples were analyzed using the thermal desorption gas chromatography/mass spectrometry (TD-GC/MS) method. The concentrations of particulate PAHs ranged from 1.26–13.93 ng/m3 with a mean value of 2.57 ng/m3, dominated by 4-ring species. Phenanthrene (Phe) and fluoranthene (Flu) were the two most abundant species, accounting for 13% and 18%, respectively. The dominant sources of PAHs were coal and biomass burning. The inhalation cancer risk value in our study exceeded 1 × 10−6 but was below 1 × 10−4, implying that the inhalation cancer risk of PAHs at the TC site is acceptable. The average concertation of n-alkanes was 103.21 ng/m3 (ranging from 38.58 to 191.44 ng/m3), and C25 was the most abundant species. Both PAHs and n-alkanes showed higher concentrations in autumn and winter whilst these values were lowest in summer. The carbon preference index (CPI) and percent contribution of wax n-alkanes showed that biogenic sources were the major sources. The annual average contributions of higher plant wax to n-alkanes at TC were over 40%.

Occupational exposure to air pollutants emitted from in situ burning of offshore oil spills: a large-scale field study.

In-situ burning (ISB) could be an effective cleanup method during spills. This study aims to study occupational exposure to pollutants emitted from offshore, large-scale ISB-experiments among personnel on vessels involved in ISB. Six experimental ISBs after release of 4.2-6 m3 crude or refined oils were performed. Air measurements on three vessels were taken of particulate matter (PM) of different size fractions, polycyclic aromatic hydrocarbons (PAH) and volatile organic compounds (VOC). One vessel was located upwind (about 80-140 m) from the burning oil while two work boats were positioned 200-400 m downwind. One of the work boats moved back and forth transverse to the smoke plume while the other followed the edge of the smoke plume downwind. During the burn period (28-63 min) the range of mean concentrations of PM2.5 particles in the closest work boat downwind from the burn (0.068-0.616 mg/m3) was considerably higher than in the upwind vessel (0.0198-0.029 mg/m3) and in the work boat moving downwind at the edge of the visible smoke (0.007-0.078 mg/m3). The particles were mainly in the PM<1 fraction. In the work boat closest to the burn the mean concentration of particulate PAH and VOC was 0.046-0.070 ng/m3 and < limit of detection -17.1 ppm, respectively. The mean PM2.5 levels in the closest vessel varied between 4 and 41 times higher than the 24-hour Norwegian Air Quality Criteria for the general population, indicating that the particulate exposure may impose a health risk for personnel up to 400 m downwind from an ISB. Exposure to VOC and PAH among crew on board vessels both upwind and downwind from the burning was low during these conditions. However, it is recommended that crew on vessels close to and downwind of smoke plumes from oil fires should use half-masks with P3 filters.

Phase partitioning effects on seasonal compositions and distributions of terrigenous polycyclic aromatic hydrocarbons along the South China Sea and East China Sea

Polycyclic aromatic hydrocarbons (PAHs) have posed serious risk to marine ecosystems due to their carcinogenic properties, and persistence in the environment and elevated bioaccumulation. It, therefore, becomes essential to examine spatial distribution, composition, and sources of PAHs. In this study, we have examined these PAH variations in the South China Sea (SCS) and East China Sea (ECS), that are experiencing rapid population and economic growth by the surrounding developing countries. It revealed high seasonal variations that significantly differ between dissolved and particulate PAHs concentrations. Spatial variations of PAHs across sites remain relatively insignificant. Persistently high particulate concentrations of the Naphthalene (Nap) were observed, whereas the dissolved concentrations of Fluorene (Flu) and Phenanthrene (Phen) remained prevalent across all the seasons. The result of non-metric multidimensional scaling (NMDS) strongly reflects the weak dispersions of PAHs across the seasons and the contrasting effects of the phase partitioning. Principal component analysis indicates that the primary source of PAH contamination is coal tar or petroleum distillation. However, estimated risk quotient (RQ) values of both the dissolved and particulate PAHs in all the seasons are far below the high-risk levels, while dissolved PAHs displayed relatively higher values. This study signifies the importance of phase petitioning for PAHs monitoring and potential risk assessments.

Profile of atmospheric particulate PAHs near busy roadway in tropical megacity, India

Objective: This study focuses on the profile of ambient particulate polycyclic aromatic hydrocarbons (PAHs), their seasonal distribution, source identification and human health risk assessment due to inhalation exposure of ambient PAHs in Delhi, India. Materials and Methods: Two sampling sites were chosen, one at roadway (MH) and other at urban background (JNU) site in Delhi. Determination of PAHs was carried with the help of HPLC with UV detector. Principal component analysis and Molecular diagnostic ratios were used for the source apportionment of PAHs. Health risks associated with inhalation of particulate PAHs were assessed using benzo(a)pyrene equivalent concentration and incremental lifetime cancer risk (ILCR) approach. Results: The results showed that the average mass concentration of Σ16 PAHs near roadway (67.8 ± 40.2 ng m−3) is significantly higher than urban background site (56 ± 30 ng m−3). Moreover, source apportionment study indicated that major PAH-emission sources in Delhi NCR are traffic and coal combustion. ILCR values at both the sites fall in the range of 10−2–10−4 that corresponds to the priority risk level (10−3) and higher than the acceptable risk level (10−6). conclusions: The high PAHs concentration at MH site was due to it’s nearness to busy traffic area. Thus, the spatial variations in PAHs were influenced by local emission sources. The high PAHs level during the winter season can be due to their higher emissions from local heating sources, shift of gas/particle partitioning toward the particulate phase at low temperature and reduced photochemical degradation of some PAHs in winter. The low level of PAHs in monsoon season can be attributed to their wet scavenging and higher percentage in vapor phase. PCA showed that the emissions from vehicles predominate at MH site; whereas, coal combustion and traffic both are the significant PAHs sources at JNU site. Health risk assessment revealed that the highest exposure risks occur at busy traffic site, thereby indicating a significantly higher health risk to the population of Delhi.

Characteristics of Atmospheric Particle-bound Polycyclic Aromatic Compounds over the Himalayan Middle Hills: Implications for Sources and Health Risk Assessment

This study was conducted in the Central Himalayan middle hills to understand the nature of polycyclic aromatic hydrocarbons (PAHs) embedded in aerosol particles, their sources and human health risk assessments. The level of sum of 15 particle-phase PAHs was between 9 and 335 ng/m3, with an average concentration of 73±66 ng/m3. There were strong seasonal differences in total suspended particles (TSP) and particle-bound PAH concentrations with higher concentrations in winter, followed by pre-monsoon and lowest in monsoon. The main contributor to the suspended particles was 5-ring PAHs (32%), followed by 4-ring (29%), 6-ring (28%), and 3-ring PAHs (11%). Conversely, the gas-phase PAHs showed that 3-ring PAHs contributed utmost to the total particles. The molecular ratios and principal component analysis indicated that both petrogenic and pyrogenic sources, particularly fossil fuel combustion, biomass combustion, and car exhausts, were the major sources of PAHs. The overall average Benzo (a)pyrene equivalent concentration of particulate PAHs was 11.71 ng/m3, which substantially exceeded the WHO guideline (1 ng/m3), and indicated the potential health risks for local residents. The average lifetime inhalation cancer risk (ILCR) estimates associated with carcinogenic PAHs was 8.78×10−6 for adults, suggesting the possible cancer risk and 2.47×10−5 for children, signifying extreme carcinogenic effects of PAHs on children’s health. Therefore, strict measures should be taken to reduce PAHs emissions in the region.

Occurrence and Distribution of Polycyclic Aromatic Hydrocarbons in the Marine Surface Microlayer of an Industrialized Coastal Area in the Eastern Mediterranean

Concentrations of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) were determined seasonally in sea surface microlayer (SML) and sub-surface water (SSW) within the Saronicos Gulf, Greece, close to a highly industrialized coastal zone. For the 16 US EPA priority PAHs, the sum of dissolved PAHs (∑dPAHs) concentrations ranged from 40.4 to 237 ng L−1 in SML, 22.8–180 ng L−1 in SSW0.2, whereas the corresponding concentrations in suspended particulate matter (∑pPAHs) were 30.8 to 177 ng L−1 and 36.8–171 ng L−1, respectively. The enrichment factor (EF) for dissolved ∑dPAHs varied from 0.9 to 2.1 with a mean value of 1.5 (n = 10) being statistically significantly greater than unity, whereas for particulate ∑pPAHs, no enrichment of the SML was reported. Enrichment factors of 5–6 ring PAHs were higher near the industrial zone. The possible sources, fate, and toxicity of PAHs are also discussed.

Seasonal variations of atmospheric polycyclic aromatic hydrocarbons (PAHs) surrounding Chaohu Lake, China: Source, partitioning behavior, and lung cancer risk

The gas-particle partitioning, source, and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons (PAHs) in different seasons were investigated in a megacity of China with coal dominating the energy structure over one year period. The total concentrations of 16 U.S. EPA priority PAHs (Σ16PAHs) were highest in winter (gaseous: 36.6 ± 1.89 ng m−3; PM phase: 16.9 ± 10.2 ng m−3) and lowest in summer (gaseous: 4.78 ± 1.48; PM phase: 2.28 ± 1.26), and followed the sequence of urban site > tourist site > rural site. In addition, rural site had higher particulate PAH concentrations in summer, autumn, and winter than other sites, primarily due to the extensive biomass burning. Low molecular weight (LMW) PAHs (2- and 3-ring PAHs) were the dominating compounds in gaseous phase, which was quite different from the high molecular weight (HMW) PAHs (4- to 6-ring PAHs) predominating in the particulate phase. The fractions of LMW PAHs showed a declining trend with the decrease of particle size for all seasons. The gas-particle partitioning of PAHs was controlled by organic carbon absorption and primarily influenced by the particle sizes. Petrogenic, traffic emission, biomass burning, and coal combustion were the main sources of atmospheric PAHs, which contributed to 33%, 35%, 32%, and 32% in spring, summer, autumn, and winter, respectively. The overall population attributable fraction (PAF) for lung cancer due to inhalation exposure to PAHs was 0.78‰ (interquartile range (IR) = 0.17–2.4‰), corresponding to the excess annual lung cancer incidence rates of 6.6 × 10−8, 1.2 × 10−8, and 2.0 × 10−7 for children, adolescents, and adults, respectively.

The relationship between black carbon and polycyclic aromatic hydrocarbon exposures and mortality in Allegheny County, Pennsylvania

Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are components of fine particulate matter associated with adverse health outcomes. However, limited work has examined the effects of PM constituents on mortality risk. Our multiple regression analysis evaluated the association of estimated neighborhood-level average fine particulate matter (PM2.5), BC, and PAH concentrations for 2013 obtained from local-scale land use regression models with 2007–2011 census tract-level age-adjusted non-accidental, cardiovascular, pulmonary, cancer, and other mortality rates in Allegheny County, PA. Models were further adjusted for census tract-level race, education, and health insurance status. In our adjusted models, estimated pollutant concentrations were not consistently associated with mortality. Only one model’s effect estimate did not include the null value, although the relationship was opposite of our original hypothesis. An interquartile range (0.25 μg/m3) increase in BC concentration was associated with a 5.9% (95% CI − 11.07, − 0.36%) decrease in log-transformed cancer mortality. However, in all mortality categories, education and health insurance covariates had a robust association with outcomes. We did not find a consistent relationship between pollutant exposures and age-adjusted mortality rates in Allegheny County, PA. However, having health insurance and having greater than a high school diploma were associated with lower mortality risk.

Temporal Variations of Polycyclic Aromatic Hydrocarbons in the Seawater at Tsukumo Bay, Noto Peninsula, Japan, during 2014-2018.

Concentrations of phase-partitioning 13 polycyclic aromatic hydrocarbons (PAHs) in seawater were investigated in the Tsukumo Bay, Noto Peninsula, Japan, during 2014–2018, to improve the understanding of the environmental behavior of PAHs in the coastal areas of the Japan Sea. Total PAH (particulate plus dissolved) concentrations in surface seawater were in the range 0.24–2.20 ng L−1 (mean 0.89 ng L−1), an order of magnitude lower than the mean values observed in the Japan Sea in 2008 and 2010. Although the PAH contamination levels during 2014–2018 were significantly lower than those in the East China Sea, the levels increased from 2014 to 2017 and were maintained at the higher level during 2017–2018. The main sources of particulate and dissolved PAHs during 2014–2018 were combustion products, of which the former were more influenced by liquid fossil-fuel combustion and the latter by biomass or coal combustion. The increase in particulate PAH concentrations in October–December during 2014–2018 was due to the impact of PAH-rich airmasses transported from the East Asian landmass in the northwesterly winter monsoon winds. The increase in dissolved PAH levels during July–September in 2014, 2016, 2017, and 2018 indicates that the Tsukumo Bay is possibly impacted by the PAH-rich summer continental shelf water transported by the Coastal Branch of the Tsushima Warm Current, which flows into the Japan Sea from the East China Sea.

Impact of the COVID-19 Outbreak on the Long-range Transport of Particulate PAHs in East Asia

Particulate polycyclic aromatic hydrocarbons (PAHs) were continuously observed at Kanazawa University Wajima Air Monitoring Station (KUWAMS), a background site located in western Japan and downwind of mainland China that is constantly under the influence of polluted air masses originating from China. The observations showed that the concentration of particulate PAHs at KUWAMS sharply dropped to the lowest level (62 pg m–3) of the cold season in the last 5 years after the implementation of COVID-19 control measures in China. Despite the occasional dilution with clean air, the decrease in PAHs at KUWAMS reflected the reduction in emission intensity in China. Moreover, the PAH concentrations at KUWAMS in February, March, and April of 2020 compared with the same period in the previous year decreased by 52.6%, 36.6%, and 36.7%, respectively. These changes were consistent with the decline in SO2 and NO2 in northern China, which intensified during the control of COVID-19 and was slightly moderated after the resumption of work. In addition, there was little change in the composition of PAHs at KUWAMS before and during the COVID-19 outbreak and compared with previous years, which suggests a stable source composition. These findings emphasize the importance of decreased emission intensity in China for reducing long-range transport of PAHs and pollution levels in downwind areas.

Temporal Trend of the Major Contributors for the Particulate Polycyclic Aromatic Hydrocarbons (PAHs) in Seoul

ABSTRACT To evaluate the effectiveness of the air quality management policies in Northeast Asia, especially in China and South Korea, temporal variation in the major contributors of the observed particulate polycyclic aromatic hydrocarbons (PAHs) in Seoul between 2002 and 2013 was estimated via receptor modeling. In addition, analyses of the air parcel movement and the statistics related to energy usage and PAH emissions in the region were conducted to validate the modeling results. Five factors were identified: coal usage for coke ovens, residential coal use, vehicular emission, biomass burning, and other emission sources. It was found that the PAH concentration in the ambient air in Seoul has been affected not only by domestic emissions but also by transported PAHs originating outside Korea, such as emissions from coal use in China and biomass burning in Northeast Asia. In addition, the impact from North Korea was verified for the PAHs emitted from biomass burning. The contribution of coal combustion decreased while that of vehicular sources increased during the study period; the contribution from biomass burning, however, remained consistent. Despite uncertainties in the modeling results, which are discussed in this paper, this study demonstrates that the air quality management policies in China and South Korea have been successful in reducing particulate PAH emissions.

Seasonal characteristics of particulate polycyclic aromatic hydrocarbons (PAHs) in a petrochemical and oil refinery industrial area on the west coast of South Korea

The Daesan industrial complex is one of the largest petrochemical and oil refinery industrial complexes in South Korea, which is believed to be a major source of polycyclic aromatic hydrocarbons (PAHs). Total suspended particle (TSP) samples (n = 84) were seasonally collected at two industrial sites and one residential site, and 19 PAHs were analyzed. Concentrations of individual PAHs ranged from 0.01 to 2.52 ng/m3, and annual mean concentrations of Σ19 PAHs at Sites 1, 2, and 3 were 5.88, 4.52, and 5.08 ng/m3, respectively. The concentrations of Σ19 PAHs in warm seasons (spring and summer) were lower than those in cold seasons (autumn and winter). Annual fractions of low molecular weight (LMW)-PAHs (2–3 rings, 12.1%) and high molecular weight (HMW)-PAHs (4–7 rings, 87.9%) indicated a strong contribution of thermal processes. Significant correlations between Σ19 PAHs and TSP (p < 0.01) at all the sampling sites were observed, implying that increased TSP levels were responsible for elevated levels of PAHs. There were strong seasonal variations in the profiles of PAHs, and they were clearly reflected in the results of the principal component analysis. Diagnostic ratios and backward air trajectories suggested seasonal variations in the contribution of local emissions and long-range transport. The diagnostic ratios suggested that mixed sources were dominant in cold seasons, while coal/biomass burning and non-traffic sources were prevailing in warm seasons. BeP/BaP ratios indicated that local emissions were major sources compared with long-range transport except for summer. Backward air trajectories in winter suggested the influence of long-range transport, but local emissions were more important in this study area.

Contribution of Biomass Burning to Ambient Particulate Polycyclic Aromatic Hydrocarbons at a Regional Background Site in East China

Biomass burning has a significant impact on regional air quality, public health, and climate change. It is an important source of particulate polycyclic aromatic hydrocarbons (PAHs), which make up a major class of toxic air pollutants. To estimate the contribution of biomass burning to ambient particulate PAH concentrations, 15 PAHs and three anhydrosugars (levoglucosan, galactosan, and mannosan) were analyzed in particulate samples collected at a background site in east China from August 2012 to August 2015. Higher concentrations of all species were observed in fall and winter. Indoor biofuel combustion in north China was considered to be the major contributor to the high concentrations of anhydrosugars in fall and winter, because there were few fires detected on a fire count map for this period. A tracer-based approach, using the ratio of PAHs to levoglucosan (PAHs/lev) in fresh biomass burning aerosols, was proposed and used to estimate the contribution of biomass burning to PAHs. The results showed th...

Endocrine disruption and carcinogenesis: Evaluation of neoplasms in endocrine organs of rat in Carbendazim carcinogenic chronic study

This study presents the seasonal size distribution of particulate polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the atmosphere. Particles were sampled from October 2009 to October 2010 on a seasonal basis using a cascade impactor collecting six size fractions at a rural and urban site in the Brno area, Czech Republic. Higher concentrations of PAHs, PCDD/Fs and dl-PCBs were observed in cold seasons at both sites, attributed to the seasonality of the gas-particle partitioning, the increase of emissions and the lower boundary mixing layer in winter. All of the compounds showed a strong accumulation in the fine fraction, with, on average, 71% of ΣPAHs, 73% of ΣPCDD/Fs and 60% of Σdl-PCBs associated with particles <0.95 μm. The human risk assessment via inhalation was addressed and followed the same pattern as for concentrations, with 41 and 7 times higher risk in winter compared to summer at the rural and urban sites, respectively. More than 70% of cancer risks of PAHs, PCDD/Fs and dl-PCBs was associated with particles <0.95 μm. Moreover, an overestimation of the cancer risk via inhalation of up to 50% occurred when the size distribution of related compounds was not considered.

Source apportionment and toxicity of atmospheric polycyclic aromatic hydrocarbons by PMF: Quantifying the influence of coal usage in Taiyuan, China

Atmospheric polycyclic aromatic hydrocarbons (PAHs) were analyzed in the gas phase and total suspended particulate (TSP) from summer 2014 to spring 2015 in Taiyuan, northern China. Taiyuan is an area with some of the highest atmospheric PAH levels in the world, and the total PAHs was highest in winter, followed by autumn, spring and summer. Low air temperature and a southern wind with low speed often led to higher PAH levels in Taiyuan. Although less than a half fraction, the benzo[a]pyrene equivalent concentration (BEQ) of particulate PAHs was almost equal to that of the total PAHs. Four sources, coal combustion, vehicle emissions, coke processing and biomass burning, were determined by positive matrix factorization (PMF), with contributions of 41.36%, 24.74%, 19.71% and 14.18% to the total PAHs in Taiyuan, respectively. Compared with the total PAHs, the particulate PAH solution underestimated the contribution of the coke processing, especially in winter, and overestimated vehicle emissions. The coke processing had a greater contribution to atmospheric PAHs with a southern wind at low speeds in winter in Taiyuan. Ultimately, the coke plants distributed in the Taiyuan-Linfen-Yuncheng basin should receive greater attention for air quality improvement in Taiyuan.