PAH Concentrations Research Articles

Experimental and numerical investigation on effect of butanol isomers additions in iso-octane sooting transition chemistry

The effects of four butanol isomers additions on sooting transition process were studied in iso-octane counterflow diffusion flame combining flame luminosity characteristics and gas-phase combustion chemistry. Flame luminosity characteristics was obtained to determine the sooting transition points of all investigated flames with homemade image processing and transition point extraction methods. The results indicated that the delay effect has occurred on sooting transition point in four blended flames with a little difference. Gas-phase combustion chemistry of the different flames in sooting transition process was studied experimentally by an online GC system as well as numerically by kinetic analysis realized with two distinct kinetic mechanisms. In addition, soot formation characteristics have also been qualitatively analyzed with soot model. Experiments and simulations show that, depending on the butanol isomer, the intermediate species production is clearly different. These different species pools play an important role on soot formation pathways as demonstrated by the simulations. Although n-butanol and sec-butanol were weaker in benzene formation, stronger C2H2 production capacity was dominant in PAHs growth. Tert-butanol had the highest C6H6 concentration with a ratio of 7 %−15 % higher than the other isomers due to the strongest IC4H8 production capacity. Therefore, its flame also has the highest PAHs concentration. Both effect mechanisms existed in iso-butanol blended flame.

Random forest insights in prioritizing factors and risk areas of soil polycyclic aromatic hydrocarbons in an urban agglomeration area

Changes in the soil environment due to urbanization pose a challenge to predict the health risks from soil PAHs on a regional scale. The sources and distributions of PAHs in the soil of the Changsha–Zhuzhou–Xiangtan Urban Agglomeration in China were analyzed using positive matrix factorization (PMF), GIS mapping, and the Random Forest (RF) model to estimate the spatiotemporal variations in health risks. The measured concentration of PAHs in the soil ranged from 20.1 to 15,233.1 μg/kg with a mean of 493.2 μg/kg. PMF and diagnostic ratios identified the primary sources of soil PAHs as transportation and coal combustion (59.1 %), soil–air exchange processes (20.5 %), and petroleum products (20.4 %). Transportation and industrial coal combustion contributed to 81.9 % and 81.7 % of the total health risks to children and adults, respectively. Locations of major point sources were identified by PMF and GIS mapping and were distributed at the congestive overpasses in urban areas and industrial enterprises carrying out large-scale coal combustion. The RF model suggested an increase, by 33.2 %, of areas with ILCRs exceeding the risk threshold if the population increases by 50.0 % in 2035. Areas with a PD > 500 p/km2, RD > 2 km/km2, and DNS < 15 km pose a high probability of health risks on local residents. The integrated approach enhanced the reliability of apportioning sources and risk assessment, serving as a reference for early warnings and a basis for soil surveys in urban areas.

Regional and seasonal drivers of metals and PAHs concentrations in road dust and their health implications in the Czech Republic

While car exhaust emissions in the EU are clearly decreasing, the future of non-exhaust emissions looks more pessimistic. The relative importance of the latter is thus expected to increase in terms of air quality and human health. The aim of the study was to assess regional and seasonal differences in the chemical composition of road dust across the Czech Republic and the health impact of its resuspension, with special respect to polycyclic aromatic hydrocarbons and metals. The road dust samples across all regions and seasons were collected. Based on subsequent laboratory and statistical processing, the spatiotemporal distribution of elements and PAHs was evaluated. Next, the contribution of road dust resuspension to air concentrations was estimated and related health impacts were assessed. A significant regional and seasonal variations in PAHs and metals were discovered. Air quality, leading to atmospheric deposition, was the most important factor contributing to these variations. In contrast, road traffic intensity played only a minor role in influencing the concentrations of metals and PAHs in road dust. Exposure to the PM10 fraction of road dust led to an increase in premature mortality, postneonatal infant mortality, and the prevalence, occurrence, and incidence of bronchitis by several percent. It also significantly raises the annual rate of emergency respiratory hospitalizations and the number of days per year using bronchodilators. Exposure to PAHs and heavy metals in road dust causes cancer incidence on the order of a few cases per 10 million people. Air quality protection measures that lead to a decrease in atmospheric deposition rates are required for the effective reduction of health risks associated with particle resuspension by traffic.

Co-pyrolysis of rubber seed oil and industrial hemp stem: Asym2sig deconvolution, thermal behavior, synergistic reaction and kinetic

Evaluation of Kinetic triplets and thermodynamics of the co-pyrolysis of industrial hemp stem (IHS) and rubber seed oil (RSO) contributes to the efficient utilization of agricultural waste. The thermodynamics and kinetics of four pseudo components from mixture (RSO: IHS=1: 1) are investigated using Asym2sig deconvolution. The results show that the Eα of pseudo hemicellulose, pseudo cellulose, pseudo triglyceride and pseudo lignin are 76.019, 193.587, 231.764 and 408.552 kJ/mol. The average differences in Eα and ΔH for the four pseudo-fractions also are 4.439, 4.929, 5.576 and 6.018 kJ/mol. Lower energy barrier favors the reaction. The frequency factor values for four pseudo-components pyrolysis are 1.07 × 108 s−1 for pseudo hemicellulose, 1.78 × 1019 s−1 for pseudo cellulose, 6.04 × 1018 s−1 for pseudo triglyceride, and 6.96 × 1031 s−1 for pseudo lignin. The four pseudo-components have different pyrolysis reaction mechanisms. The synergistic effect calculations show a significant interaction between RSO and IHS. According to thermodynamic analysis, the pyrolysis of the four pseudo components requires the provision of external energy. FT-IR results indicate that RSO can significantly increase the release of C2H2, C2H4, C2H6 and CH4 during the co-pyrolysis of RSO and IHS. The co-pyrolysis of IHS and RSO can increase the content of alkene, alkane and MAHs, which improve the quality of bio-oil significantly. Besides, it can reduce the content of PAHs, which reduces the viscosity of the bio-oil. The results can provide new insights into the synergistic and efficient disposal of triglycerides and lignocellulosic biomass.

Effects of Polycyclic Aromatic Hydrocarbons on Soil Bacterial and Fungal Communities in Soils

Soil organic pollution (such as heavy metals, PAHs, etc.) has caused serious environmental problems, which have resulted in unexpected effects on contaminated soil ecosystems. However, knowledge of the interactions between environmental PAHs and bacterial and fungal communities is still limited. In this study, soil samples from different PAH-contaminated areas including non-contaminated areas (NC), low-contaminated areas (LC), and high-contaminated areas (HC) were selected. Results of toxic equivalent quantity (TEQ) indicated that Benzo[a]pyrene (BaP) and Dibenzo[a,h]anthracene (DBahA) constituted the main TEQs of ∑16PAHs. Incremental lifetime cancer risk (ILCR) assessment revealed that the main pathway of exposure to soil PAHs was dermal contact in adults and children. Furthermore, adults faced a higher total cancer risk (including dermal contact, ingestion, and inhalation) from soil PAHs than children. The microbial community composition analysis demonstrated that soil PAHs could decrease the diversity of bacterial and fungal communities. The relative abundance of Acidobacteriota, Gemmatimonadota, Fimicutes, Bacteroidota, Ascomycota, and Basidiomycota exhibited varying degrees of changes under different concentrations of PAHs. Benzo[a]anthracene (BaA) and Chrysene (Chr) drove the bacterial community composition, while BaP and DBahA drove the fungal community compositions. Co-occurrence network analysis revealed the high contamination levels of PAHs that could change the relationships among different microorganisms and reduce the complexity and stability of fungal and bacterial networks. Overall, these findings provide comprehensive insight into the responses of bacterial and fungal communities to PAHs.

Origin of biomarkers (PAH, n-alkane, hopane, estrane) in different colors of plastic resin pellets and surface sediments from coastal area of the Makuran-Oman Sea

The unique attributes of the study area, situated near the Strait of Hormuz—an extensively utilized oil shipping corridor for Iran and neighboring Arabian nations—encompass oil extraction and exploitation, the establishment of an oil export hub, the advancement of petrochemical industries, as well as tourism and transportation activities. This research represents the first examination of the sources of plastic resin pellet release, addressing both local and non-local contributions. To conduct this study, samples of plastic resin pellet and coastal and intertidal surface sediments were collected from seven stations on the shores of the Oman Sea in Hormozgan province (Sirik, Garook, Ziarat, Karpan, Koohestak, Gohardo, and Kargan) with four replications to determine the origin and spatial distribution pattern of hydrocarbons and the diffusion source of plastic resin pellets (offshore or regional). Plastic resin pellets were separated based on color (white, yellow, brown, and black). Soxhlet was used to extract hydrocarbons, two stages of column chromatography were used to separate compounds, and gas chromatography–mass spectrometry (GC–MS) was used to identify and determine their concentration. The total n-alkanes concentration ranged from 2940 to 18,711 (μg/g) in coastal surface sediments, from 19,721–1678 (μg/g) in intertidal surface sediments, and from 11,481.50 to 55,601.41 (μg/g) in plastic resin pellets. A similar trend was found for the total PAH concentration which ranged from 135.57 to 3890.62 (ng/g) in coastal sediments, from 1820.28 to 6579.55 (ng/g) in intertidal sediments, and from 3714.19 to 66/1920451 (ng/g) in plastic resin pellets. According to the sediment pollution criteria, a high pollution level was assessed in most of the stations. In most of the surface sediments and plastic resin pellets, the presence of unresolved complex mixture (UCM), the carbon preference index (CPI) lower than 1, and the diagnostic ratios of PAH, hopane, and sterane compounds indicated petrogenic origin for hydrocarbons. The results of principal component analysis based on 16 diagnostic ratios of PAH, n-alkane, hopane, and sterane compounds showed that brown and black plastic resin pellets were placed in a different group than the coastal and intertidal sediments and white and yellow plastic resin pellets. Most likely, the diffusion source of brown and black plastic resin pellets is different and through open water.

Spatiotemporal variations of PM2.5 organic molecular markers in five central cities of the Yangtze River Delta, East China in autumn and winter: Implications for regional and local sources of organic aerosols

Information on the spatiotemporal variations in the composition and sources of organic aerosols (OA) is needed to identify regional influences and to establish effective control measures. Here, 23-h PM2.5 samples were collected in five central cities of the Yangtze River Delta in eastern China, including Nanjing, Suzhou, Wuxi, Changzhou, and Zhenjiang, every three days from 2020/09/01 to 2021/02/28. Each sample was analyzed for water-soluble inorganic ions, organic carbon (OC), elemental carbon (EC), and organic molecular markers (OMMs). Generally, the major components of PM2.5, including NH4+, SO42−, NO3−, OC, and EC, exhibited similar temporal patterns across the five cities. In all OMM groups, the concentrations of PAHs, oxygenated PAHs, and secondary products of isoprene showed strong correlations (r = 0.79 ± 0.050–0.93 ± 0.028) and low coefficient of divergence (COD = 0.22 ± 0.024–0.30 ± 0.033) between sampling sites, indicating a homogeneous spatial distribution of industrial emissions and biogenic secondary OA in autumn and winter. Other OMMs showed wider r (e.g., steranes and hopanes, 0.20–0.80) and COD (0.26–0.69) ranges for all site pairs, probably due to the influence of local emissions. Based on the source apportionment results using Positive matrix factorization, the biomass burning factor dominated the contribution to OC and EC in winter and showed strong correlations (r = 0.84 ± 0.063) between the sampling sites, indicating regional transport of emissions from biomass burning and fossil fuel combustion in the heating season. Traffic-related factors had the greatest spatial heterogeneity (r = 0.27 ± 0.19–0.51 ± 0.16) and contributed significantly to OC at their maximum levels.

Changes in exposure to environmental contaminants in the aftermath of Hurricane Maria among pregnant women in northern Puerto Rico

Experiencing a hurricane during pregnancy is associated with increased risk of adverse birth outcomes and poor mental health. Pregnant people from marginalized communities are more susceptible to adverse effects, as they have fewer resources to overcome hardships at a time when shelter and nutrition are essential. When Hurricane Maria (HM) devastated Puerto Rico in September 2017, the archipelago was already burdened with high poverty, health disparities, environmental contamination, and fragile utility infrastructure. We aimed to compare biomarkers of environmental exposures among pregnant participants in the PROTECT cohort before and after HM and to identify hurricane-related sources of exposure. Metals, PAHs, phthalate metabolites, and phenols were measured in urine samples collected from participants at three prenatal visits (2011–2019). Samples were categorized as before, <3 months, 3–6 months, and >6 months after HM. Using linear mixed effects models, we found that in the 6 months after HM, participants had higher Co, Ni, and DEHPTP concentrations, indicating increased exposure, and lower concentrations of PAHs, several metals, and phthalates, suggesting decreased exposure, compared to pre-HM levels. Biomarkers were not associated with potential exposure sources assessed through questionnaire or previously measured tap water contaminants. This study provides insight into how extreme weather events may alter environmental exposures among pregnant people in Puerto Rico. As climate change has increased the frequency and magnitude of such events, additional research is needed to clarify the implications for maternal and child health and to identify sources of related environmental exposures within this vulnerable population.

Variability of PAH Patterns in Upper Forest Soil (Sub)horizons—A Case Study From South‐Central Poland

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are a class of contaminants characterized by their persistent and toxic nature. This study examines the variability in PAH distribution patterns in the upper layers of forest soils, focusing on the influence of different characteristics of individual soil (sub)horizons. A total of 130 samples were collected from five forest areas in south‐central Poland and analyzed for the 16 priority PAHs. Samples were taken from the organic fermentative‐humic (Ofh), humic (A), and humic‐eluvial (AE) (sub)horizons. The highest mean concentrations of total PAHs were found in the subhorizon‐Ofh (Ofh—1547 μg kg−1, A—1103 μg kg−1, AE—109 μg kg−1). The PAH content was significantly correlated with SOM content and pH, but this correlation was only significant in the horizon‐A. The percentage contributions of 3‐, 4‐, 5‐, and 6‐ring compounds to the total PAHs varied among the investigated soil (sub)horizons. The subhorizon‐Ofh had the highest percentage contribution of 6‐ring PAHs, 4‐ and 5‐ring PAHs were most prevalent in the horizon‐A, while 3‐ring compounds in the horizon‐AE. The variability in PAH patterns was also reflected in individual PAH ratios (BaA/BaA+Chr, IcdP/IcdP+BghiP), confirming the different behavior of 4‐, 5‐, and 6‐ring compounds in these (sub)horizons. This suggests that the retention of PAHs in the investigated (sub)horizons is influenced by several factors, including pH, degree of SOM decomposition, and mineral fraction, each to a different extent. Our findings reveal significant knowledge gaps regarding the behavior and accumulation of PAHs in soil (sub)horizons, underscoring the need for further research.

Hygienic assessment of heavy metal and organic compounds pollution in snow cover of a multi-industrial city

Introduction. One of the leading health risk factors is atmospheric air pollution, the state of which can be indirectly assessed by the content of a wide range of pollutants in snow and soil cover. Materials and methods. The study analyzed data on deposits of polycyclic aromatic compounds (PAHs), heavy metals (HMs) and petroleum hydrocarbons (PHs) in the snow of different functional zones of the agglomeration. Physicochemical research methods were used. Results. The content of ΣPAHs was found to range from 412.8 to 2843.7 ng/L. The highest concentrations of ∑PAHs were observed in the residential area in the square (point 10) – 2843.7 ng/L; and on the border of the sanitary protection and residential zones in the area of the Yuzhnaya station (point 3) – 1758.2 ng/L. The share of benzo(a)pyrene (B(a)P) from ∑PAH ranged from 2.9 to 9.7%. PHs levels ranged from 51.0–117.0 μg/L. The difference in the range of fluctuations in values was most evident in the content of individual PAHs: B(a)P (16.13 times), Ant (12.05 times) and B(g,h,i)P (11.56 times ), mercury (17.53 times), zinc (9 times) and manganese (8.58 times); metals: cadmium (1.89 times), copper (1.75 times), and lead (1.47 times). Limitations. Sampling and features of snow cover contamination by atmospheric precipitation in the dynamics of the winter season. Conclusion. Concentrations of PAHs and HM varied in different ranges of values and had a non-uniform spatial distribution over the territory. Direct links were found between the content of B(a)P and other polyarenes in the snow cover.

Does higher ratio of wheat straw addition decrease PAHs degradation in PAHs-contaminated paddy soils and PAHs concentrations in rice?

There are considerable studies focusing on impacts of straw returning on PAHs degradation and bioavailability in PAHs-contaminated upland soils, while similar research in paddy soils is limited. Incubation experiments and pot trials were conducted to study effects of straw returning on PAHs degradation in paddy soils and PAHs accumulation in rice, respectively. There are threshold effects of straw returning on PAHs degradation in PAHs-contaminated paddy soils. The inflection point of PAHs degrading was recorded under 0.8 % wheat straw treatment (conventional (CS) and pretreated wheat straw (PS)), which increased PAHs degradation by 18.13–32.36 %. The lowest PAHs concentrations in rice were recorded under 1 % straw (CS and PS) treatment, which was attributed to the highest PAHs degradation in rhizosphere soils. Compared to CS treatment, PS treatment significantly (p < 0.05) increased PAHs degradation by 7.93–10.28 % and PAHs concentrations in rice by 12.38–45.87 % due to that increasing dissolved organic carbon (DOC) enhanced PAHs concentrations in porewater of rhizosphere soils. Higher diversity enhanced the metabolic pathways and function genes to degrade PAHs by improving bacterial phenotypes and biochemical processes under 1 % wheat straw and PS treatment. The present study firstly demonstrated that the effects of straw returning on PAHs degradation in PAHs-contaminated paddy soils and PAHs concentrations in rice depended on amount and methods of straw returning.

Environmental risks and agronomic benefits of industrial sewage sludge-derived biochar

The main objective of the present work was to assess the ecotoxicological safety of the use of thermochemically treated sewage sludge from the wastewater treatment plant (WWTP) of a distillery plant as a soil additive in agricultural soils based on its physicochemical characteristics and the bioaccumulation of selected elements in the plant tissues of maize (Zea mays). We have carried out physicochemical characterization (pH, EC, Corg, Cinorg, CEC, N, H, ash content, PAHs) of sewage sludge feedstock (SS) and sludge-derived biochar (BC) produced by slow pyrolysis at a temperature of 400 °C. The effect of 1% (w/w) amendment of SS and BC on soil physicochemical properties (pH, EC, Cinorg), germination of ryegrass, soil rhizobacteria and microorganisms, as well as on the accumulation and translocation of selected elements in maize (Zea mays) was studied. The results show that pyrolysis treatment of distillery WWTP sludge at 400 °C increases pH (from 7.3 to 7.7), Corg(from 28.86% to 36.83%), N (from 6.19% to 7.53%), ash content (from 23.59% to 50.99%) and decreases EC (from 2.35 mS/cm to 1.06 mS/cm), CEC (from 118.66 cmol/kg to 55.66 cmol/kg), H (from 6.76% to 1.98%) and Σ18 PAHs content (from 4.03 mg/kg to 3.38 mg/kg). RFA analysis of SS and BC showed that pyrolysis treatment multiplies chromium (Cr) (2.2 times), nickel (Ni) (2.96 times), lead (Pb) (2.13 times), zinc (Zn) (2.79 times), iron (Fe) (1.26 times) in the obtained BC, but based on an ecotoxicological test with earthworms Eisenia fetida, we conclude that pyrolysis treatment reduced the amount of available forms of heavy metals in BC compared to SS. We demonstrated by a pot experiment with a maize that a 1% addition of BC increased soil pH, decreased EC and Cinorg and had no significant effect on heavy metal accumulation in plant tissues. According to the results of the three-level germination test, it also does not affect the germination of cress seeds (Lepidium sativum). There was a significant effect of 1% BC addition on soil microbial community, and we observed a decrease in total microbial biomass and an increase in fungal species variability in the soil. Based on these results, we conclude that BC represents a promising material that can serve as a soil additive and source of nutritionally important elements after optimization of the pyrolysis process.

The effects of photochemical aging and interactions with secondary organic aerosols on cellular toxicity of combustion particles

Fine particulate matter (PM2.5) is associated with numerous adverse health effects, including pulmonary and cardiovascular diseases and premature death. Significant contributors to ambient PM2.5 include combustion particles and secondary organic aerosols (SOA). Combustion particles enter the atmosphere and undergo an aging process that changes their shape and composition, but there is limited study on the health effects of combustion particle aging and interactions with SOA. This study aimed to understand how biological responses to combustion particles would be affected by atmospheric aging and interaction with anthropogenic SOA. Fresh combustion particles underwent photochemical aging in a potential aerosol mass (PAM) oxidation flow reactor and interacted with SOA produced by the oxidation of toluene vapor in the PAM reactor. Photochemical aging and SOA interactions lead to significant changes in the PAH content and oxidative potential of the particle. Photochemical aging and SOA interactions also affected the biological responses, such as the inflammatory response and CYP1A1 induction of the particles in monoculture and coculture cells. These findings highlight the significance of photochemical aging and SOA interactions on the composition and cellular responses of combustion particles.

Ecological and Geochemical Assessment of the State of Soils in the City of Baikalsk According to the Content of Polycyclic Aromatic Hydrocarbons

The pollution of the topsoils of the city of Baikalsk (Irkutsk region) under the influence of industrial emissions and wastes of the Baikal Pulp and Paper Mill (BPPM) was studied. The content of 16 individual PAH structures in samples of urban and background soils taken during the soil geochemical survey in the summer of 2019 was analyzed. Relatively low levels of PAH content were found in the lignin sludge from the BPPM and СHP ash. The concentration of total PAHs in CHP ash reaches 46 mg/ kg with a predominance of low molecular weight compounds (the proportion of naphthalene and its homologues is 24% and 34% of the total PAHs, respectively), among high molecular weight PAHs, 5-nuclear benzo(b)fluoranthene dominates (16%). In lignin sludge, the amount of PAHs is 7.16 mg/kg with the predominance of benzo(b)fluoranthene (83%). In the soils of Baikalsk, the average total content of PAHs (38.4 mg/kg) is 5 times higher than the background content. In urban soils, 4–5-nuclear fluoranthene (61.1%) and benzo(b)fluoranthene (29.4%) prevail. This makes it possible to attribute soil pollution to the fluoranthene type. The soils of the motor transport (total PAH 105 mg/kg) and industrial (59.5 mg/ kg) zones are the most polluted, where the most contrasting PAH anomalies were formed. In descending order of the amount of PAHs, the land use zones of the city form a series: motor transport industrial residential one-storey railway transport residential multi-storey recreational zone. Several local anomalies in the amount of PAHs are distinguished, forming two large pollution halos in the western and eastern parts of the city. The leading factors in the accumulation of high molecular weight PAHs in soils are acid-alkaline conditions and soil organic matter, while the accumulation of low molecular weight polyarenes is mainly controlled by pH. The environmental hazard of pollution of Baikalsk soils with polyarenes is due to benzo(b)fluoranthene, its contribution is 83.5%.

Impact of salinity on PAH and halogenated PAH contamination and risks during the pickling of Chinese pickles

In this study, solid-phase extraction coupled with gas chromatography–triple quadrupole mass spectrometry was used for analyzing PAHs and XPAHs in pickles. The concentrations were 43.0±3.9 μg/kg for PAH24 (including EPA PAH 16 and EU PAH15+1) and 0.52±0.07 μg/kg for XPAH18 (including 11 chlorinated PAHs and 7 brominated PAHs) in commercially available xuecai, and 28.3±8.7 μg/kg for PAH24 and 0.25±0.11 μg/kg for XPAH18 in laboratory-pickled radish. Throughout the pickling process, concentrations of PAHs generally decreased, while XPAHs in xuecai and chlorinated PAHs (ClPAHs) in radish initially increased before declining. The elevated ClPAH levels in fermented radish compared to their unfermented counterparts, along with the newly formed 1-chlorinated pyrene in xuecai, highlighted the generation of ClPAHs during pickling. At lower salinity levels, the greater reduction in concentrations of PAHs corresponds with the largest increase in ClPAHs, suggesting potential chlorination of some PAHs into ClPAHs via microbial activity. Although concentrations of ClPAHs rose after pickling, the toxic equivalent quotients of PAH42 (including PAH24 and XPAH18) in pickles after fermentation were lower than those in both unfermented and fermenting samples, indicating that mature pickles did not increase the overall toxicity risk associated with PAHs and XPAHs.

Evaluating emissions and air quality implications of residential waste incineration

In Europe mainly at winter season the PM levels exceed air quality limits, which correlated with the operation of solid-fired boilers. More and more people are returning to using these devices due to energy shortage caused by the pandemic and regional conflicts. In addition, the phenomena of co-burning fuels and municipal waste in residential boilers in primarily fuel poverty households increases further the amount of pollutants in the atmosphere. This study aims to correlate the quantity and quality of air pollutants with the type of fuel (wood and wastes) burned. Combustion experiments were conducted using oak fuel mixed with three waste groups: (1) plastics (PP, HDPE, PET); (2) textiles (polyester—PES, cotton—COT); and (3) papers (cardboard—CARD, glossy coated paper—GCP, 84C/PAP). The addition of waste to wood fuel altered the morphology of emitted particles. While waste burning doesn't always increase particle quantity, it significantly raises PAH concentrations. A strong relationship exists between waste type, particle morphology, and PAH quality, where with lower molecular weight PAHs linked to tar agglomerates and higher ones to soot agglomerates with inorganic crystals.

Distributions of polycyclic aromatic hydrocarbons in ambient air samples from Hanoi urban areas, Vietnam, and its implications for inhalation exposure.

Sixteen PAHs in ambient air samples collected from residential and roadside areas in the Hanoi metropolitan were investigated. Total PAH concentrations in the ambient air samples ranged from 45.0 to 451ng/m3. Among PAHs, phenanthrene was found at the most abundant and highest levels. The distributions of PAHs in the ambient air collected in the dry season were on average 26% higher than in the wet season. The PAH concentrations in the air samples collected from the traffic areas were significantly higher (about 2.7 times) than those in the residential areas, indicating that these chemicals originated from motor vehicles. According to vertical, the PAH concentrations found in the ambient air samples collected from the ground floor were significantly higher than on the upper level, however, there was not much difference when going higher (from 24m (8th floor) to 111m (37th floor)). The human exposure doses were estimated for two age groups (adults and children) based on the measured PAH concentrations, the inhalation rates, and body weights. The estimated exposure doses to PAHs through inhalation for adults/children were 1.13/2.86 (ng/kg-bw/d) (residential areas) and 3.24/8.18 (ng/kg-bw/d) (traffic areas), respectively. The average lifetime excess cancer risk (ECR) from inhalation exposure to PAHs was 3.0 × 10-4 at the traffic areas and 1.4 × 10-4 at the residential areas. These estimated exposure doses were above the acceptable level of the California Environmental Protection Agency (CalEPA) Office of Environmental Health Hazard Assessment (1*10-6).

Risks and sources of atmospheric particulate-bound polycyclic aromatic hydrocarbons (AP-PAHs) in seven regions of China: A review

Many studies have shown that atmospheric particulate-bound polycyclic aromatic hydrocarbons (AP-PAHs) pose carcinogenic and noncarcinogenic risks to human health. However, few studies have investigated the health risks of AP-PAHs across regional or national cities. Therefore, in this literature review, >6971 individual atmospheric samples from 89 cities in seven regions of China were obtained. The PAH contents in these samples were measured in accordance with national standards (HJ 784, 2016). AP-PAH contents (0.5–1.2 × 103 ng/m3) significantly increased in Chinese cities during 2002–2017. The contamination levels based on toxic equivalent quantities (0.6–1.4 × 102 ng/m3) were lower in the four southern regions than in the three northern regions. The health risks associated with AP-PAH exposure in different age group followed the following order: infants < kindergarten students < primary school students < middle school students < adults. This study revealed that AP-PAHs pose potential ecological risks and have adverse biological effects, and the mean effect range median quotient in 73 cities (82.0% of 89 cities) indicated moderate or high risk. Clustering analysis revealed that the primary sources of AP-PAHs are coal, petroleum, and biomass combustion. These results can be used to achieve AP-PAH pollution control in Chinese cities and worldwide.

Winter indoor air quality in traditional Mongolian yurts, in a Ger district of Ulaanbaatar

In Ulaanbaatar roughly 60 % of the population live in traditional Mongolian yurts in the so-called Ger districts of the city. Winter indoor air quality is a serious concern in these districts as about 98 % of households consume solid fossil fuel (mainly coal). In our study, indoor air quality was assessed based on PAHs analysis and ecotoxicity testing of 24-hour samples collected in 4 yurts. Three of the selected yurts were equipped with conventional while the fourth one with improved stoves. Analysis of PAHs profiles showed the prevalence of higher molecular weight PAHs in all yurts. Concentrations of the 5-ring benzo(b)fluoranthene and 6-ring benzo(g.h.i)perylene were extremely high in one yurt using conventional stove, 8430 µg g−1 and 6320 µg g−1, respectively. Ecotoxicity of the samples was assessed using the kinetic version of the Vibrio fischeri bioluminescence inhibition bioassay. In concordance with PAHs concentrations, ecotoxicity was also the highest in that yurt.

Using DPF to Control Particulate Matter Emissions from Ships to Ensure the Sustainable Development of the Shipping Industry

PM (particulate matter) emissions from ships are the main sources of marine atmosphere pollution. Controlling the emissions of particulate matter from ships is related to the sustainable development of the shipping industry. To reduce PM emissions from marine four-stroke diesel engines, DPFs are effective. Our results show that DPF had more than 90% capturing efficiency for both the number and mass emissions of PM, and the capturing efficiency for the accumulation mode was higher than that of the nuclear mode. DPF can also significantly reduce the chemical components of PM in marine diesel exhaust gas. The removal efficiencies for OC and EC were 89.7–91.6% and 84.8–92.8%, respectively, with each particle size range showing over 80% efficiency. SO42− was the ion with the highest content, followed by NH4+, NO3−, Na+, NO2−, and Cl−, with their reduced proportions remaining consistent with the removal efficiency of particulate matter. DPF can also effectively reduce PAH content and toxicity. The use of DPF can greatly improve the impact of ship emissions on the marine atmospheric environment. The appropriate DPF with the best performance can be selected according to the exhaust parameters and particle size distributions with different characteristics.