Screening-Level Emission Factors and Semi-Quantitative Toxic Equivalency of Polycyclic and Nitro-Polycyclic Aromatic Hydrocarbons from Residential Biomass Combustion in Chile
Residential heater replacement programs in Chile have been evaluated primarily through fine particulate matter (PM) reduction metrics, without considering chemical speciation of the organic aerosols. This screening-level study characterized and compared particle-bound polycyclic aromatic hydrocarbon (PAH) and nitro-PAH emission factors from a residential firewood and a wood pellet heater, under controlled combustion conditions, and assessed their potential toxic equivalency (BaP-TEQ). Compound quantification used 1-nitropyrene as an index calibration compound; all results are semi-quantitative estimates with a combined analytical uncertainty of approximately 13–32%. Firewood combustion yielded a PAH-dominated emission profile with a total BaP-TEQ EF of 187.8 ng/kg, driven primarily by benzo[a]pyrene (BaP; individual contribution: 183.9 ng/kg). Wood pellet combustion showed a nitro-PAH-dominated profile under the applied semi-quantitative analytical conditions, with concentrations expressed as 1-nitropyrene-equivalent estimates and several compounds identified tentatively by NIST library matching, yielding a total screening-level BaP-TEQ EF of 972.1 ng/kg, approximately five-fold higher than firewood under the applied TEF framework and driven primarily by 6-nitrochrysene (toxic equivalency factor, TEF = 10). This screening-level estimate should not be interpreted as a direct human health risk between the two heating systems. Mean PM emission factors were 1.05 ± 0.55 g/kg for firewood combustion and 0.69 ± 0.15 g/kg for pellet combustion (approximately 1.5-fold difference). These results are reported descriptively given the screening-level nature of the analysis. The shift in particulate chemical profile from PAH-dominated in the firewood system to nitro-PAH-dominated in the pellet system suggests that wood pellets from pine may not be a sustainable approach to address air quality problems in Chile, since reductions in PM emissions alone may not capture relevant differences in the organic toxicological profile between these combustion systems. These findings provide a regional baseline for the chemical speciation of residential biomass emissions in Chile.
The results showed that no age group is fully protected, highlighting the need to include FA, AA, and acrolein in Brazilian air quality standards, to implement stricter controls on vehicle emissions, and to establish extensive, continuous atmospheric monitoring.
Mateus S. Moreira, Lícia P. S. Cruz· Air quality, atmosphere and...· 0 citations
Nitrogen-containing organic compounds (NOCs) are key characteristic components in particulate matter (PM) from household solid fuel combustion, yet their personal exposure and class-dependent toxicity remain poorly characterized. We compared size-resolved personal exposure to particulate nitrated phenols (NPs) and nitro-PAHs (n-PAHs) among rural users of clean coal (CC), raw coal chunk (RCC), and biomass (BB), and evaluated representative compounds in A549 cells. Biomass users had the highest PM2.5-bound n-PAH exposure (up to 11.5-fold above clean coal), while NPs varied little across fuel groups (≤1.3-fold); CC and RCC users showed comparable PM2.5-bound NPs concentrations (64.0 ± 12.1 vs 57.4 ± 25.8 ng m–3, P = 0.545). n-PAHs exhibited greater cytotoxicity with lower IC50 values, whereas NPs produced stronger NF-κB activation by larger increases in p-IκB-α and COX-2 expression. Physicochemical descriptor analysis and molecular docking suggested that divergent biological responses may be partly attributable to differing hydrophobicity and protein interaction modes: hydrophobic contacts for n-PAHs, polar and hydrogen-bonding interactions for NPs. These results demonstrate clean heating transitions better mitigate n-PAH than NP exposure. NPs and n-PAHs differ substantially in cytotoxicity and NF-κB-mediated inflammation, providing a case study linking real-world personal exposure monitoring to molecular toxicology for health-risk-based prioritization of combustion-derived PM constituents.
Rong Feng, Hong-Mei Xu, Zhen-Xing Shen et al.· Environmental Science &...· 0 citations
This study evaluated the concentrations of polycyclic aromatic hydrocarbons (PAHs) in soil, water, and edible plants within cashew nut processing clusters in Enugu, Nigeria. Following liquid–liquid and solid–liquid extractions, the concentration of sixteen PAHs congeners were determined using gas chromatography coupled with a flame ionization detector (GC‐FID). To predict the potential sources of these PAHs, a diagnostic ratio guide was employed and principal component analysis was performed. Mutagenic equivalent concentration, human health risk assessment, and ecological risk assessment were performed. The identified PAHs had concentration range: 786.31–2589.46 µg/kg in soil, 33.78–5476.37 µg/L in water, and 561.47–3047.84 µg/kg in vegetables. Except for one location, the vegetables had higher levels of low molecular weight PAHs, while high molecular weight PAHs were more prevalent in the water. The results showed that the studied location has a fair amount of PAH pollution, mostly from pyrogenic sources though the source apportionment models predicted multi‐sources. The ecological risk assessment indicated acenaphthene to be the most contributing contaminant while the health risk evaluations indicated that consumers of water and vegetables from this area may have risk for non‐carcinogenic health problems. There were substantial mutagenic equivalent quantities, and BaP metabolites were probably responsible. The study reveals that inefficient burning of biomass and fossil fuels has resulted in significant levels of PAH contamination in the surrounding cashew nut processing clusters, and these activities should be controlled.
Edidiong S. Akwaowo, H. Abugu, J. Ihedioha· CLEAN - Soil, Air, Water· 0 citations
Polycyclic aromatic hydrocarbons (PAHs) in soils of energy chemical industrial plants pose considerable ecological and health risks. However, comprehensive studies between petrochemical and coal chemical plants in arid Northwest China remain limited. In this study, 75 surface soil samples (0-20 cm) were collected from 15 large-scale plants (four petrochemical and 11 coal chemical plants) across the region. Sixteen priority PAHs (∑PAHs) were quantified, and source apportionment was conducted using diagnostic ratios and principal component analysis-multiple linear regression (PCA-MLR). In addition, health risks were evaluated using toxic equivalence factors and incremental lifetime cancer risk (ILCR) models. Results showed a stark contrast in PAHs concentrations, with coal chemical plants averaging 4652.2 ng/g and reaching up to 188,506.0 ng/g at a coal tar processing site, compared to 225.6 ng/g in petrochemical plants. Four-ring PAHs were predominant, accounting for 64.5% and 52.1% of total PAHs in coal chemical and petrochemical soils, respectively, indicative of high-temperature combustion sources. PCA-MLR analysis identified coal combustion as the dominant source at coal chemical sites (96.5%), while petrochemical sites exhibited mixed sources, including oil leakage (49.6%) and vehicular emissions (25.6%). Health risk assessment revealed that ILCR values exceeded the US EPA threshold of 10-6 at seven sampling points in coal chemical plants, with the highest risk observed at site BXT-2 (1.99 × 10-4), primarily driven by dermal and oral exposure to benzo[a]pyrene. These findings highlight the urgent need for stricter control of high-temperature industrial processes and improved management of hazardous waste in energy chemical industrial plants.
Meng-Cheng Wu, Yun-Zhou Tan, Guo-dong Kang et al.· Journal of Environmental Qua...· 0 citations
The inhalation of fine particulate matter (PM) containing polycyclic aromatic hydrocarbons (PAHs) poses significant health and environmental risks due to the potential bioaccessibility of these toxic compounds in the human respiratory system. This study investigates the inhalation bioaccessibility of PAHs associated with fly ash produced from the combustion of petroleum-derived fuels (local diesel, pure diesel, kerosene, asphalt, and crude oil) and waste tyres. Fly ash samples were collected from the different sample materials and analyzed for 16 priority PAHs using gas chromatography-mass spectrometry (GC-MS). The extent to which a substance becomes available for absorption in the body was assessed using artificial lysosomal fluid (ALF) to simulate human lung conditions over exposure periods from 48 hours up to 96 hours. The results revealed that high-molecular-weight PAHs such as benzo [a] pyrene (BaP), fluoranthene, and pyrene were the most bioaccessible, particularly in fly ash from pure diesel and tyre combustion. the degree to which polycyclic aromatic hydrocarbons (PAHs) in fly ash from different petroleum products and waste tyres are available for absorption in the body, varied significantly across fuel types, with waste tyre and diesel fly ash exhibiting the highest values. The findings underscore the importance of considering inhalation bioaccessibility when assessing the health risks of airborne PAHs from combustion sources. This study provides critical insights for air quality management and emphasizes the need for stricter controls on emissions from petroleum product use and waste tyre incineration.
Nwafor Hanachor, Boisa Ndokiari, Konne Lelesi et al.· Journal of Health and Enviro...· 0 citations
The spatial distribution, sources and ecological risk of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) in surface soil from Liuxin area, Xuzhou, China was investigated in this study. Gas chromatography-mass spectrometry analysis revealed ΣPAH concentrations ranging from 115.66 to 373.53 ng ⋅g−1 (mean: 196.26 ng ⋅ g−1), with phenanthrene (Phe) exhibiting the highest mean concentration (51.18 ng ⋅ g−1). Spatial analysis demonstrated a southeast-to-northwest concentration gradient, with maximum PAH levels observed in southeastern zones. PAH composition showed dominance of low-molecular-weight species (2, 3 rings: 46.7%), followed by 5, 6 ring PAHs (28.3%), and 4-ring compounds (24.9%). Source apportionment using molecular diagnostic ratios and positive matrix factorization identified four primary contributors: coal-fired power generation & metallurgical emissions (34%), biomass combustion (31%), diesel fuel combustion/leakage (29%), traffic emissions (6%). Ecological risk assessment employing Dutch soil quality standards revealed localized exceedances in southeastern areas, particularly for fluoranthene (Fla) and Phe. However, toxic equivalency quotients remained low, with incremental lifetime cancer risks below 10−6 for all exposure pathways. These findings indicate that while PAH contamination warrants monitoring, current levels pose negligible carcinogenic risk to the local population.
Jin-Xian He, Chen-Long Ding, Pei-Lin Sun et al.· Environmental Research Commu...· 0 citations
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