Particle-bound Polycyclic Aromatic Hydrocarbons Research Articles

Pollution characteristics, source apportionment and absorption spectra of size-resolved PAHs in atmospheric particles in a cold megacity of China

Polycyclic aromatic hydrocarbons (PAHs) have the capability for solar radiation absorption related to climate forcing. Herein, pollution characteristics and absorption spectra of size-resolved PAHs in atmospheric particles in a cold megacity were comprehensively investigated. The mean concentrations of Σ18PAHs in all the 11 particle size ranges were 3.95 ± 4.77 ×104pg/m3 and 2.17 ± 1.54 ×103pg/m3 in heating period (HP) and non-heating period (NHP), respectively. Except for most PAHs with 2 and 3 benzene rings in NHP, most other PAHs showed a unimodal distribution pattern with the peak at 0.56-1.0 μm in both periods, which was caused by PAH emission sources. The PAH-related climate forcing was mainly caused by the solar radiation absorptions at ~325 (~330) nm and ~365nm. In general, the absorption intensities were higher in HP than NHP. The absorption intensity in the particle size range of 0.56-1.0 μm was the highest, and benzo[e]pyrene was the dominant contributor. In colder periods in HP, higher PAH concentrations caused more intensive PAHs-related climate forcing. This study provided new insights for pollution characteristics and absorption spectra of size-resolved PAHs in atmospheric particles, which will be useful for better understanding PAH-related climate forcing. Environmental ImplicationsPolycyclic aromatic hydrocarbons (PAHs) are a kind of brown carbon, which have the capability for solar radiation absorption related to climate forcing. Pollution characteristics of size-resolved PAHs can affect the concentration-corrected absorption spectra of particle-bound PAHs. In this study, the pollution characteristics, source apportionment, and absorption spectra of size-resolved PAHs in atmospheric particles in a cold megacity (Harbin City in Northeastern China) were comprehensively investigated. This study provided new insights for pollution characteristics and absorption spectra of size-resolved PAHs in atmospheric particles, which will be useful for better understanding on PAH-related climate forcing.

Spatiotemporal Gradients of PAH Concentrations in Greek Cities and Associated Exposure Impacts.

To study the spatiotemporal variability of particle-bound polycyclic aromatic hydrocarbons (PAHs) and assess their carcinogenic potential in six contrasting urban environments in Greece, a total of 305 filter samples were collected and analyzed. Sampling sites included a variety of urban background, traffic (Athens, Ioannina and Heraklion), rural (Xanthi) and near-port locations (Piraeus and Volos). When considering the sum of 16 U.S. EPA priority PAHs, as well as that of the six EU-proposed members, average concentrations observed across locations during summer varied moderately (0.4-2.2 ng m-3) and independently of the population of each site, with the highest values observed in the areas of Piraeus and Volos that are affected by port and industrial activities. Winter levels were significantly higher and more spatially variable compared to summer, with the seasonal enhancement ranging from 7 times in Piraeus to 98 times in Ioannina, indicating the large impact of PAH emissions from residential wood burning. Regarding benzo(a)pyrene (BaP), an IARC Group 1 carcinogen and the only EU-regulated PAH, the winter/summer ratios were 24-33 in Athens, Volos, Heraklion and Xanthi; 60 in Piraeus; and 480 in Ioannina, which is afflicted by severe wood-burning pollution events. An excellent correlation was observed between organic carbon (OC) and benzo(a)pyrene (BaP) during the cold period at all urban sites (r2 > 0.8) with stable BaP/OC slopes (0.09-0.14 × 10-3), highlighting the potential use of OC as a proxy for the estimation of BaP in winter conditions. The identified spatiotemporal contrasts, which were explored for the first time for PAHs at such a scale in the Eastern Mediterranean, provide important insights into sources and controlling atmospheric conditions and reveal large deviations in exposure risks among cities that raise the issue of environmental injustice on a national level.

Size distribution of airborne particle-bound polycyclic aromatic hydrocarbons during rice straw open burning in Hanoi, Vietnam

This study dealt with size distribution of airborne particle-bound polycyclic aromatic hydrocarbons (PAHs) during rice straw open burning (RSOB) and non-RSOB period in Hanoi. Two sampling campaigns for PAHs associated with airborne particles of six different sizes (PM0.1, PM0.1-0.5, PM0.5-1, PM1.0-2.5, PM2.5-10, PM> 10) were conducted at three sampling sites in Hanoi during 2018–2020. The average concentrations of total particle-bound PAHs were higher during RSOB period (11.7 ± 5.3 ng m−3) than during non-RSOB period (10.1 ± 5.4 ng m−3), and concentrations were significantly higher at the near-RSOB site (11.0 ± 4.9 ng m−3) than at the far-RSOB site (7.1 ± 3.4 ng m−3). Of the various PAHs, the average concentration of benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) bound to PM0.1 and PM1-2.5 exhibited the greatest significant difference in between the near- and the far-RSOB site. The size distributions of total PAHs were unimodal with the maximum concentration in accumulation mode at all sampling locations. The four-ring PAHs shifted to slightly larger particles during the RSOB period (1.34–1.5 μm) compared to the non-RSOB period (0.87 μm) or with the distant site (1 μm). The concentrations of 5- and 6-ring PAHs remained stable in smaller particles, peaking at 0.8 μm. Diagnostic ratios implied biomass burning contributes to PAHs emissions in all sampling sites, while vehicular emission are the significant emission source in the far-RSOB site. This result provides a comprehensive understanding of the size distribution of particle-bound PAHs in the air during RSOB, and useful information for the intergrated air quality management in RSOB regions.

Assessment of air pollution emitted during cooking using biomass and cleaner fuels in the Shiselweni region of Eswatini (Swaziland)

AbstractIn Eswatini, 62.3% of households still rely on solid fuel for cooking, especially wood (61.8%). Smoke emissions during biomass burning remain the primary source of indoor air pollution, comprising pollutants detrimental to health. This study provides a quantitative exposure assessment of fuels used in the Shiselweni region with the objectives of monitoring the carbon monoxide (CO) and carbon dioxide (CO2) concentrations during cooking events and evaluating cancer and noncancer risks due to exposure to particulate-bound polycyclic aromatic hydrocarbons (PAHs) during cooking events among cooking personnel in households that cook indoors by burning biomass. Real-time CO, CO2, and particulate matter (PM) monitoring was performed in seventeen kitchens during cooking events across the Shiselweni region using different cooking methods: biomass in open fires and stoves, liquefied petroleum gas (LPG), and electric stoves. PM2.5, PM10, and CO exceeded indoor exposure guidelines for biomass fuel-related homesteads. Particulate PAH intake concentrations were evaluated, and biomass fuel users exhibited high cancer risks and low embryo survival chances due to particulate PAH exposure. The average total cost of reducing the incremental lifetime cancer risk (ILCR) and hazard quotient (HQ) to acceptable levels was lower when shifting from biomass to LPG stoves than when shifting to electric stoves. Graphical abstract

Toxicity of particles derived from combustion of Ethiopian traditional biomass fuels in human bronchial and macrophage-like cells

The combustion of traditional fuels in low-income countries, including those in sub-Saharan Africa, leads to extensive indoor particle exposure. Yet, the related health consequences in this context are understudied. This study aimed to evaluate the in vitro toxicity of combustion-derived particles relevant for Sub-Saharan household environments. Particles (< 2.5 µm) were collected using a high-volume sampler during combustion of traditional Ethiopian biomass fuels: cow dung, eucalyptus wood and eucalyptus charcoal. Diesel exhaust particles (DEP, NIST 2975) served as reference particles. The highest levels of particle-bound polycyclic aromatic hydrocarbons (PAHs) were found in wood (3219 ng/mg), followed by dung (618 ng/mg), charcoal (136 ng/mg) and DEP (118 ng/mg) (GC–MS). BEAS-2B bronchial epithelial cells and THP-1 derived macrophages were exposed to particle suspensions (1–150 µg/mL) for 24 h. All particles induced concentration-dependent genotoxicity (comet assay) but no pro-inflammatory cytokine release in epithelial cells, whereas dung and wood particles also induced concentration-dependent cytotoxicity (Alamar Blue). Only wood particles induced concentration-dependent cytotoxicity and genotoxicity in macrophage-like cells, while dung particles were unique at increasing secretion of pro-inflammatory cytokines (IL-6, IL-8, TNF-α). In summary, particles derived from combustion of less energy dense fuels like dung and wood had a higher PAH content and were more cytotoxic in epithelial cells. In addition, the least energy dense and cheapest fuel, dung, also induced pro-inflammatory effects in macrophage-like cells. These findings highlight the influence of fuel type on the toxic profile of the emitted particles and warrant further research to understand and mitigate health effects of indoor air pollution.

Traffic and Industrial Contributions of Particle-Bound PAHs during an Air Pollution Event in the Metropolitan Area of Medellin-Colombia: Inhalation Intake Risk during Pregnancy

Traffic and Industrial Contributions of Particle-Bound PAHs during an Air Pollution Event in the Metropolitan Area of Medellin-Colombia: Inhalation Intake Risk during Pregnancy

Enhanced mitigation of inhalable particles and fine particle-bound PAHs from a novel hazardous waste-power plant candidate

Emissions of the inhalable particle (dp < 10 μm, PM10) and their harmful compositions from combustion sources have high potential on health risk with nearly no regulation. This study investigates the particle size distribution (PSD), as well as the removal mechanism of PM10 and fine particle (FP)-bound polycyclic aromatic hydrocarbons (PAHs) from the flue gas of a hazardous waste thermal treatment system. It has ultralow regulated emission and becomes a candidate of power generation module. A series of the advanced scrubbers, cyclonic demister, and baghouse was equipped for multi-pollutant control. The moderate or intense low oxygen dilution (MILD) combustion effectively inhibited the PM2.5 generation by volumetric oxidation. Advanced scrubbers removed PM1, PM2.5, and PM10 by 85.24, 68.68, and 97.60%, respectively, which achieved by local supersaturation, heterogeneous condensation of water vapor, and the growth of fine PM. Moreover, the scrubbers effectively scavenged the course PM10 containing the high-molecular-weight PAH homologs onto the water phase but promoted the condensation and absorption of the lighter homologs onto the fine particle surface (dp ∼5.3 μm). The size window (dp = 0.3–1.0 μm) of the minimum efficiency reporting value of a BH filtration led to the peak of FP-PAH mass and BaP equivalent (BaPeq) toxicity at dp = 0.1–0.4 and 0.1–0.8 μm, respectively. Consequently, the synergy of MILD combustion and the SCB-CYC-BH system effectively inhibited the PM2.5, PM10, PM2.5-PAHs, and FP-PAH levels from a waste thermal treatment process and further mitigated the potential health risk.

A novel exfoliated graphite-based device for passive sampling and detection of polycyclic aromatic hydrocarbons in air

Water scarcity is a major problem in the Sub-Saharan Africa, as such rainwater harvesting is considered as an alternative source of water. However, air pollution may affect the quality of taken rainwater. Specifically, particle-bound polycyclic aromatic hydrocarbons (PAHs) a class of persistent organic pollutants (POPs) known to have toxic effects on human beings and environmental sectors. In this study, a novel electrode material called exfoliated graphite (EG) was synthesized and used as sorbent material in fabrication of passive sampler and electrode device for the monitoring of polycyclic aromatic hydrocarbons (PAHs) in air. The surface morphology, structure, surface functionality of the materials were investigated using, Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) techniques. A sorption kinetic’s evaluation of EG was conducted. It was found that EG has shown an outstanding affinity towards detection of PAHs with maximum partition coefficients. Moreover, EG electrode-based device was developed and utilized for detection of PAHs in air through electrochemical technique. This was conducted by exposing the sampler to PAHs gases for 12 days, thereafter it was transferred to a blank supporting electrolyte and analyzed using differential pulse voltammetry (DPV). The EG-based tubular sampler was calibrated in a laboratory flow-through exposure experiment. Furthermore, the effects of time and pollutants concentration were examined under controlled experimental conditions. Most importantly, extraction of the sampler was performed, followed by determination of PAHs using gas chromatography-mass spectrometer (GC–MS). As the result, uptake of PAHs onto the EG tubular based sampler was observed with linear uptake throughout the exposure time. Interestingly, an increasing of uptake by PAHs was indicated when the concentration of the pollutant was increased. These results imply that EG showed a great potential and preferable candidate for monitoring of PAHs in air.

Effectiveness of a covered oil-free cooking process on the abatement of air pollutants from cooking meats

Cooking events can generate household air pollutants that deteriorate indoor air quality (IAQ), which poses a threat to human health and well-being. In this study, the emission characteristics and emission factors (EFs) of air pollutants of different meats (beef, lamb, chicken, pork, and fish) cooked by a novel oil-free process and common with-oil processes were investigated. Oil-free cooking tends to emit lower total volatile organic compound (TVOC) levels and fewer submicron smoke particles and can reduce the intake of fat and calories. However, TVOC emissions during oil-free cooking were significantly different, and the lamb EFs were nearly 8 times higher than those during with-oil cooking. The particle-bound polycyclic aromatic hydrocarbon (ƩPPAH) and benzo(a)pyrene-equivalent (ƩBaPeq) EFs during with-oil cooking ranged from 76.1 to 140.5 ng/g and 7.7–12.4 ng/g, respectively, while those during oil-free cooking ranged from 41.0 to 176.6 ng/g and 5.4–47.6 ng/g, respectively. The ƩPPAH EFs of chicken, pork, and fish were lower during oil-free cooking than during cooking with oil. Furthermore, the ƩBaPeq EFs of beef, chicken, pork, and fish were lower during oil-free cooking than during cooking with oil. Therefore, it is recommended to use the oil-free method to cook chicken, pork, and fish to reduce ƩPPAH and ƩBaPeq emissions, but not recommended to cook lamb due to the increase of ƩBaPeq emissions. The with-oil uncovered cooking EFs of aldehydes ranged from 3.77 to 22.09 μg/g, and those of oil-free cooking ranged from 4.88 to 19.96 μg/g. The aldehyde EFs were lower during oil-free covered cooking than with-oil uncovered cooking for beef, chicken, and fish. This study provides a better realizing of new cooking approaches for the reduction of cooking-induced emission, but further research on the effects of food composition (moisture and fat) and characteristics is needed.

Molecular distribution, sources and potential health risks of fine particulate-bound polycyclic aromatic hydrocarbons during high pollution episodes in a subtropical urban city

Abundance of fine particulate-bound 16 priority polycyclic aromatic hydrocarbons (PAHs) was investigated to ascertain its sources and potential carcinogenic health risks in Varanasi, India. The city represents a typical urban settlement of South Asia having particulate exposure manyfold higher than standard with reports of pollution induced mortalities and morbidities. Fine particulates (PM2.5) were monitored from October 2019 to May 2020, with 32% of monitoring days accounting ≥100 μgm−3 of PM2.5 concentration, frequently from November to January (99% of monitoring days). The concentration of 16 priority PAHs varied from 24.1 to 44.6 ngm−3 (mean: 33.1 ± 3.2 ngm−3) without much seasonal deviations. Both low (LMW, 56%) and high molecular weight (HMW, 44%) PAHs were abundant, with Fluoranthene (3.9 ± 0.4ngm−3) and Fluorene (3.5 ± 0.3ngm−3) emerged as most dominating PAHs. Concentration of Benzo(a)pyrene (B(a)P, 0.5 ± 0.1ngm−3) was lower than the national standard as it contributed 13% of total PAHs mass. Diagnostic ratios of PAH isomers indicate predominance of pyrogenic sources including emissions from biomass burning, and both from diesel and petrol-driven vehicles. Source apportionment using receptor model revealed similar observation of major PAHs contribution from biomass burning and fuel combustion (54% of source contribution) followed by coal combustion for residential heating and cooking purposes (44%). Potential toxicity of B[a]P equivalence ranged from 0.003 to 1.365 with cumulative toxicity of 2.13ngm−3. Among the PAH species, dibenzo[h]anthracene contributed maximum toxicity followed by B[a]P, together accounting 86% of PAH induced carcinogenicity. Incremental risk of developing cancer through lifetime exposure (ILCR) of PAHs was higher in children (3.3 × 10−4) with 56% contribution from LMW PAHs, primarily through ingestion and dermal contact. Adults in contrast, were more exposed to inhale airborne PAHs with cumulative ILCR of 2.2 × 10−4. However, ILCR to PM2.5 exposure is probably underestimated considering unaccounted metal abundance thus, require source-specific control measures.

Combined effects of temperature and monsoon on seasonal variations of atmospheric polycyclic aromatic hydrocarbons in the coastal Shanghai, China

An intensive sampling program was conducted at two coastal sites of megacity Shanghai - the emerging town Lingang New Area (LGNA), and the petrochemical-industry zone Jinshan Area (JSA) from July 2016–June 2017, to study the occurrence, sources, environmental behavior and fate of atmospheric polycyclic aromatic hydrocarbons (PAHs). Results showed the median concentrations of total atmospheric PAHs were 18 ng m−3 and 12 ng m−3 in JSA and LGNA, respectively, which were lower than those recently detected in northern coastal China, and previously detected in urban/suburban Shanghai. There was strong/opposite temperature dependence for gaseous and particle-bound PAHs, indicating the importance of ongoing local and nearby volatilization; While the gas-particle partitions of individual PAH compound changed dramatically with seasons, with most easily adsorbed on particles during colder months. The potential source contribution function (PSCF) and concentration weight trajectory (CWT) model demonstrated the interactions of terrestrial and marine air mass regulated by the East Asian monsoon. Specifically, PAHs released by wintertime coal heating in northern China and summertime marine shipping in East China Sea, that transported through northwest and southeast monsoon, respectively, and aggravated the pollution of coastal Shanghai, especially for the background site in LGNA. The positive matrix factorization (PMF) source apportionment suggested the dominance of petrogenic sources for gaseous PAHs, coal and biomass combustion sources for particle-bound PAHs, and further demonstrated the seasonal variations of these potential sources. Atmospheric PAHs would deposit to the coastal waters, with gaseous absorption fluxes almost an order of magnitude higher than those of particle-bound deposition.

Wintertime trends of particulate-bound polycyclic aromatic hydrocarbons (PAHs) at north-east site of India: chemical characterization and source identification

Wintertime trends of particulate-bound polycyclic aromatic hydrocarbons (PAHs) at north-east site of India: chemical characterization and source identification

Fine and ultrafine particle emission factors and new diagnostic ratios of PAHs for peat swamp forest fires

Peatland fires are one of the major global sources of atmospheric particles. Emission factors for fine (PM1 and PM2.5) and ultrafine (PM0.1) particles and particle-bound polycyclic aromatic hydrocarbons (PAHs) from plants in the peat swamp forest (PSF), including Melaleuca cajuputi leaves, M. cajuputi branches, M. cajuputi bark, Lepironia articulata (Retz.) Domin, forest leaf litter and peat were measured in a laboratory combustion chamber. From these measurements, new PAH diagnostic ratios for fine and ultrafine particles were proposed for identifying the forest burning source. The new emission factors for PM were PM0.1: 0.03–0.33, PM1: 0.69–2.11 and PM2.5: 1.12–4.18 g/kg; for PM-bound PAHs, the factors were PM0.1: 5.7–166.0, PM1: 31.5–1338.9 and PM2.5: 36.3–3641.1 μg/kg. The predominant PAHs for PSF burning were Pyr, BbF, DBA (in PM0.1), Flu, DBA, BghiPe (in PM1), and BbF, DBA and BghiPe (in PM2.5). We also presented new diagnostic ratios for PSF burning, including BaP/(BaP + Chr): 0.39–0.75, BaP/(BaP + BbF): 0.21–0.47 and BaA/(BaA + Chr): 0.36–0.53. Moreover, the physical and chemical characteristics of ambient fine and ultrafine particles in the Kuan Kreng forest during the 2019 forest fire (FF) and 2021 non-forest fire (NFF) periods were investigated. The mean PM0.1, PM1 and PM2.5 concentrations during the FF period were approximately 3.5–4.4 times as high as those during the 2021 NFF period. New PAH diagnostic ratios of BaP/(BaP + BbF) versus BaP/(BaP + Chr) were able to identify PAH burning sources in PM1 and PM2.5 but were less clear for PM0.1, which was dominated by a single source – M. cajuputi. Chemical mass balance studies identified peat forest burning emissions as the main source of fine and ultrafine particles during the FF period. This study suggests that the new PAH diagnostic ratios can be used to identify the burning source for more precise source apportionment.

Polycyclic aromatic hydrocarbons including dibenzopyrenes in indoor air samples from schools and residences in Germany

Polycyclic aromatic hydrocarbons (PAH) are several hundred organic substances that are formed in the course of incomplete combustion of organic material. Of particular importance are the carcinogenic effects of PAH. Various dibenzopyrenes as well as benzo[c]fluorene (BcFl) seems to have a particular toxicological potency, which have hardly been investigated in indoor air so far.Therefore, the indoor air samples of 27 classrooms and 35 central living spaces of residences in Germany were collected to analyze 56 particle-bound PAH as well as naphthalene (Nap).The PM10 values in schools and residences ranged between 9.1 and 210 μg/m³ (mean: 93.4 μg/m³) and from 3.6 to 52.0 μg/m³ (mean: 12.0 μg/m³), respectively. For the sum of the 16 priority US EPA PAH (except acenaphthylene and naphthalene) means (95th percentiles) in classrooms and residences were 1.20 ng/m³ (2.77 ng/m³) and 0.84 ng/m³ (2.64 ng/m³), respectively. Higher values were observed for naphthalene with mean concentrations of 596 ng/m³ (2,800 ng/m³) in classrooms and 243 ng/m³ (530 ng/m³) in residences.For classrooms and residences mean concentrations of 8.3 pg/m³ and 7.4 pg/m³ for dibenzo[a,l]pyrene (DBalPyr), 16.4 pg/m³ and 11.9 pg/m³ for dibenzo[a,e]pyrene (DBaePyr), 9.2 and 5.7 pg/m³ for dibenzo[a,h]pyrene (DBahPyr), and 6.4 and 4.2 pg/m³ for BcFl were observed, respectively, while DBaiPyr was found in only one sample above LOD.The BaPeq (benzo[a]pyrene equivalents) for the sum of 20 PAH is on average 482 pgTEQ/m³ (schools) and 393 pgTEQ/m³ (residences), which corresponds to an incremental lifetime cancer risk to 42 × 10−6 and 34 × 10−6.Although dibenzopyrenes and BcFl are found only in very low concentrations in indoor air, they have a significant impact on the risk if the assumptions about the toxicological potency of this group turn out to be valid.

Toxicity of fresh and aged anthropogenic smoke particles emitted from different burning conditions

There is substantial evidence that photochemical reactions in the atmosphere cause physico-chemical transformation of combustion smoke, but how this processing modifies potential health effects in exposed populations is not well understood. Here we utilized a new approach to simulate photochemical aging of anthropogenic smoke emissions (a mixture of plastic, plywood, and cardboard smoke) from two different burning conditions (smoldering vs. flaming) and investigated their adverse outcomes associated with mutagenic activity and the relative potencies of different polycyclic aromatic hydrocarbons (PAHs). Aging resulted in increased oxygenated volatile organic compound (VOC) emissions but largely degraded particle-bound PAH components in the smoke. Chemical transformation during aging was more dramatic for flaming versus smoldering smoke. Due to the PAH degradation, mutagenicity of the aged smoke from flaming combustion was much lower (up to 4 times) than that of the fresh smoke on per-particle mass basis. However, on the basis of particle emitted per fuel mass burned, the aged and fresh smoke particles exhibited similar mutagenic activities, which were up to 3 times higher for smoldering versus flaming smoke emissions. Similarly, the PAH toxicity equivalent (PAH-TEQ) of the aged smoldering smoke was 3 times higher than that of the aged flaming smoke particles, suggesting that some PAHs (e.g., indeno[c,d]pyrene and benzo[b]fluoranthene) in the smoldering smoke were more photochemically stable during aging. These findings increase understanding of the evolution of smoke emitted at different burning conditions and the role of photochemical transformations on mutagenicity and PAH-induced toxicity.

Effects of organic carbon/elemental carbon and particle size on inhalation bioaccessibility of particle-bound PAHs

Bioaccessible fractions of particle-bound hydrophobic organic compounds (HOCs) are critical to evaluating human inhalation exposure risk. However, the key factors for controlling the release of HOCs into the lung fluid are not adequately examined. To address this issue, eight particle size fractions (0.056–18 μm) from different particle emission sources (barbecue and smoking) were collected and incubated with an in vitro method for determining inhalation bioaccessibilities of polycyclic aromatic hydrocarbons (PAHs). The bioaccessible fractions of particle-bound PAHs were 35–65% for smoke-type charcoal, 24–62% for smokeless-type charcoal, and 44–96% for cigarette. The size distributions of bioaccessible fractions of 3–4 ring PAHs were symmetric with the patterns of their masses, characterized as a unimodal distribution with both the trough and peak at 0.56–1.0 μm. Analysis from machine learning showed that chemical hydrophobicity appeared to be the most significant factor affecting inhalation bioaccessibility of PAHs, followed by organic carbon and elemental carbon contents. Particle size seemed to have little effect on the bioaccessibility of PAHs. A compositional analysis of human inhalation exposure risk from total concentration, deposition concentration, and bioaccessible deposition concentration in alveolar region showed a shift in the key particle size from 0.56−1.0 μm to 1.0–1.8 μm and an increasing in the contributions of 2–3 ring PAHs to risk for cigarette due to the high bioaccessible fractions. These results suggested the significance of particle deposition efficiency and bioaccessible fractions of HOCs in risk assessment.

128 Exposure to soot, Measured as Black Carbon and PAH, in Swedish Chimney Sweeps

Abstract The overall aim of our research is to study chimney sweeps exposure to soot to be able to give recommendations on how to effectively reduce the exposure. To do this a suitable method to study soot exposure is required. In this study we use a new method to study the personal airborne exposure to soot measured as black carbon (BC). BC is measured with a AethLabs MA200 micro aethalometer with a flow rate of 100 mL/min and sampling time of 1 min. By using a direct-reading instrument we aim to identify variability in exposure levels during the workday, and potential work tasks contributing to elevated exposure to soot. The study includes 20 chimney sweeps performing black sweeping in Sweden and BC is measured for eight workdays for each individual. During these days individuals also fill out a diary of work tasks performed. To assess the value of the BC levels, airborne polycyclic aromatic hydrocarbon (PAH) is also measured with personal sampler for particulate- and gas phase PAH. PAH is measured in parallel with BC during one workday. Preliminary results show variability of BC levels between different individuals as well as different workdays for the same individual. We are also able to link BC levels with work tasks from the diaries. Significantly elevated PAH levels and especially the particle-bound PAHs, including the carcinogenic benzo(a)pyrene, were observed in most samples.

Optimization of the QuEChERS extraction method to determine Polycyclic Aromatic Hydrocarbons (PAHs) in powder aerosol particles collected by cyclone

Conventional methods for collecting and extracting aerosol particles are challenging in accurately characterizing particle-bound polycyclic aromatic hydrocarbons (PAHs) contamination and conducting cellular exposure studies. Therefore, developing direct aerosol sample collection and simple pretreatment analytical methods is necessary. This study describes the optimization of the QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction method for the determination of PAHs in powder-form environmental standard materials (SRM1944) and proves it is also effective for analyzing PAHs in powder aerosol particle samples collected by cyclone. In this study, we used an I-optimal design response surface method combined with a desirability function to investigate the extraction effect of PAHs under different combinations of QuEChERS extraction factors, including extraction solvent, salt, and clean-up reagent. The optimized conditions of the method were determined using the 2-factor interaction (2FI) model combined with boundary conditions, resulting in acetonitrile/dichloromethane (7:1, v/v), Na2SO4/NaCl (1:1, w/w), and primary and secondary amine (PSA) as extraction solvents, extraction salts, and clean-up reagent, respectively. The optimized method showed good recoveries of PAHs reaching 76%–118% and 85%–121% for SRM1944 and standard solution. The results for cyclone-collected ambient powder aerosol particles extracted by the optimized QuEChERS illustrated that this improved procedure has good PAHs extraction efficiency as the traditional Soxhlet method, while reducing hazardous organic solvents usage, experimental cost (per mg sample) by 97% and sample pretreatment time. Overall, this combination of “powder aerosol particle collection and modified QuEChERS extraction” provides new insight on aerosol sample collection, extraction, and in vitro/in vivo exposure studies.

Effects of particle-bound polycyclic aromatic hydrocarbons and plasticisers from different traffic sources on the human alveolar epithelial cell line A549

Road traffic represents a major source of particulate matter (PM), which is considered the most harmful pollutant for humans. This work aimed to evaluate the toxic effects of polycyclic aromatic hydrocarbons (PAHs) and plasticisers extracted from PM emitted by traffic, including exhaust samples, samples collected in a road tunnel and simultaneously in a nearby urban background atmosphere, and samples from the wear of distinct types of brakes. Different biological endpoints were investigated after exposing human alveolar epithelium A549 cells to the organic extracts: viability, cell cycle alterations and levels of intracellular reactive oxygen species (ROS). The particulate extracts from the wear of low steel brake pads induced greater decreases in cell viability. It was observed that cytotoxicity is more dependent on the individual composition of PAHs than on the global concentration. Exhaust samples from heavy-duty Euro V vehicles induced more toxic effects than Euro VI. Among Euro V vehicles, the exhaust of GTL was the most toxic. The composite weekly sample of the urban background atmosphere showed to be extremely toxic, decreasing cell viability to 2.66%, while the daily road tunnel samples caused a decrease of up to 83.6% at most. In the particulate extracts of the urban background atmosphere, retene and naphthalene were found, which were absent or present at trace levels in the tunnel. Irrespective of the sample, although some changes were observed in the A549 cell cycle after 24 h exposure in all the phases, the differences in the mean values were not great enough to exclude the possibility of random variability. When the results from the three phases (G0/G1, S and G2/M) of the cells exposed to all PM extracts were compared to the control, no statistically significant difference was detected. Regardless of the sample type, no significant increases in cellular ROS levels were observed either.

Ecotoxicity Evaluation of Fire-Extinguishing Water from Large-Scale Battery and Battery Electric Vehicle Fire Tests.

Electrified transport has multiple benefits but has also raised some concerns, for example, the flammable formulations used in lithium-ion batteries. Fires in traction batteries can be difficult to extinguish because the battery cells are well protected and hard to reach. To control the fire, firefighters must prolong the application of extinguishing media. In this work, extinguishing water from three vehicles and one battery pack fire test were analyzed for inorganic and organic pollutants, including particle-bound polycyclic aromatic hydrocarbons and soot content. Additionally, the acute toxicity of the collected extinguishing water on three aquatic species was determined. The vehicles used in the fire tests were both conventional petrol-fueled and battery electric. For all of the tests, the analysis of the extinguishing water showed high toxicity toward the tested aquatic species. Several metals and ions were found in concentrations above the corresponding surface water guideline values. Per- and polyfluoroalkyl substances were detected in concentrations ranging between 200 and 1400 ng L-1. Flushing the battery increased the concentration of per- and polyfluoroalkyl substances to 4700 ng L-1. Extinguishing water from the battery electric vehicle and the battery pack contained a higher concentration of nickel, cobalt, lithium, manganese, and fluoride compared with the water samples analyzed from the conventional vehicle.