PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs (NPAHs) in rural and suburban areas in Shandong and Henan Provinces during the 2016 Chinese New Year's holiday

Near-zero-waste processing of jarosite waste to achieve sustainability: A state-of-the-art review

Jarosite waste is a by-product generated from iron removal process in the jarosite process, which typically contains valuable metals including zinc, nickel, cobalt, silver, indium, and lead. Due to the large amount of jarosite and the less efficient and costly methods of recovering residual metals, it is mainly disposed by landfills. However, leachate generated from the landfills can release high concentrations of heavy metals, which contaminate nearby water resources and pose environmental and health risks. In this review, the environmental and resource properties of jarosite waste were briefly summarized. Then those pyrometallurgical, hydrometallurgical and biological methods were discussed. In this review, considering the polymetallic properties and the low content of valuable metal elements of the jarosite waste, it is indicated that these processes had their own benefits and drawbacks such as overall yield, economic and technical constraints, and the necessity for combined processes to recycle multiple metal ions from jarosite wastes. Finally, this paper provided a critical and systematic review of studies on the novel green recycling technology for metals and material preparation based on the jarosite waste. This review can lay a guidance for the near-zero-waste processing of jarosite waste, with a particular focus on the combination of chemical and biological processes and waste-to-materials.

Relaxation of Spring Festival Firework Regulations Leads to a Deterioration in Air Quality

The relaxation of restrictions on Chinese Spring Festival (SF) firework displays in certain regions has raised concerns due to intensive emissions exacerbating air quality deterioration. To evaluate the impacts of fireworks on air quality, a comparative investigation was conducted in a city between 2022 (restricted fireworks) and 2023 SF (unrestricted), utilizing high time-resolution field observations of particle chemical components and air quality model simulations. We observed two severe PM2.5 pollution episodes primarily triggered by firework emissions and exacerbated by static meteorology (contributing approximately 30%) during 2023 SF, contrasting with its absence in 2022. During firework displays, freshly emitted particles containing more primary inorganics (such as chloride and metals like Al, Mg, and Ba), elemental carbon, and organic compounds (including polycyclic aromatic hydrocarbons) were predominant; subsequently, aged particles with more secondary components became prevalent and continued to worsen air quality. The primary emissions from fireworks constituted 54% of the observed high PM2.5 during the displays, contributing a peak hourly PM2.5 concentration of 188 μg/m3 and representing over 70% of the ambient PM2.5. This study underscores that caution should be exercised when igniting substantial fireworks under stable meteorological conditions, considering both the primary and potential secondary effects.

Characteristics and health risk assessment of indoor and outdoor PM2.5 in a rural village, in Northeast of China: impact of coal and biomass burning

Fine particulate matter (PM2.5) has health effects that may depend on its sources and chemical composition. In this study, characteristics of PM2.5 chemical composition and health risk assessment from Songyuan, China, were investigated during day and night in indoor and outdoor from February 4 to 19, 2021. Relative high concentrations of PM2.5 were obtained in indoor environment than outdoor, with 503.95 ± 209.62 μg/m3 during the day and 357.52 ± 232.81 μg/m3 at night for the indoor environment. Relatively high total carbon, organic carbons, elemental carbons, polycyclic aromatic hydrocarbons (PAHs), and oxygenated polycyclic aromatic hydrocarbons (OPAHs) were obtained in indoor environment. However, the average concentrations of PAHs were higher during night (73.57 ± 43.09 ng/m3) in indoor and OPAHs during day (6.027 ± 2.960 ng/m3) in outdoor. They had different I/O distributions of these compounds during day and night. Indeno(1,2,3-cd) pyrene was the dominant PAHs, and benzanthrone was the dominant OPAHs; this is different with the previous studies. The high indoor/outdoor ratios showed the indoor coal and biomass burning greatly affect the indoor pollutants. Average ILCR health risk assessment for PAHs was all higher than 10-6 for different age gender, suggesting there has potential cancer risk existed for populations living in the rural coal and biomass burning area Songyuan, China.

Distinct seasonal variability of source-dependent health risks from PM2.5-bound PAHs and related derivatives in a megacity, southwest China: Implications for the significance of secondary formation

In contrast to polycyclic aromatic hydrocarbons (PAHs) which have been regularly monitored, the source-dependent health risk of their derivatives in ambient environment has not been well understood, especially regarding seasonal variability. In this study, oxygenated and nitrated PAHs (OPAHs and NPAHs) in PM_2.5 samples from different seasons in urban Chongqing were analyzed and compared with PAHs from a human health perspective. Benzo[a]pyrene equivalent concentrations (BaP_eq) were annually averaged at 6.13 ± 8.97 ng/m³ (n = 118) in the present study, with highest levels in winter followed by spring, autumn, and summer. The BaP_eq values of OPAHs were higher than PAHs in spring and summer with seasonal averaged value up to 3.7 times of that for PAHs, manifesting significant underestimation of the health impact if only PAHs were considered. Incremental lifetime cancer risk (ILCR) model results suggested that the potential cancer risks were accumulated mostly from inhalation exposure during infancy and adulthood. Furthermore, in comparison with PAHs, OPAHs, mainly 6H-Benzo[c,d]pyren-6-one, had significant contribution to cancer risks (annually averaged at 58.3 %). Source-dependent cancer risks based on positive matrix factorization model denoted secondary formed PAH derivatives as a critical contributor to cancer risk, particularly in spring and summer (attributed to about 61 % of ILCR). The enhanced secondary formation of PAH derivatives during spring and summer was partially justified by diagnostic ratios and further analysis revealed that higher temperature, higher O₃ level, and lower relative humidity besides stronger solar intensity during these two seasons as the most likely causes of this seasonal variation. Results in this study emphasizes that more knowledge on the formation and toxicity of OPAHs is imperative, especially in the context of complex PM_2.5-ozone pollution in China.

Particulate nitrated aromatic compounds from corn straw burning: Compositions, optical properties and potential health risks

Nitrated aromatic compounds (NACs) are important components of brown carbon (BrC), and their health and climate effects are of wide concern. Biomass burning is a major contributor to NACs in the atmosphere, yet NACs emitted from biomass burning are poorly constrained. In this study particulate NACs from open burning of corn straws were characterized in terms of their compositions, light absorption and toxic equivalents. 1, 6-dinitropyrene was the most abundant species among the measured nitropolycyclic aromatic hydrocarbons (NPAHs) with a share of 13.4% in total NPAHs, while 4-nitrocatechol was the most abundant nitrophenol (NP) species and accounted for 25.4% of measured NPs. 2-nitropyrene, widely used as a marker of secondary formation of NPAHs, was found to be the second most abundant NPAHs (13.3% of the total NPAHs) in the particulate matter (PM) primarily emitted from corn straw burning, and thus is inappropriate to be an indicator of the secondary formation. The measured primary NACs could only explain a negligible part (0.2%) of the light absorption by BrC. Although the concentrations of 9 toxic NACs were less than one-third of the 16 USEPA priority PAHs, their benzo(a)pyrene toxic equivalency quotients however were approximately 10 times that of the 16 PAHs. This study suggests that in comparison of PAHs from straw burning, NACs should be given greater attention due to their potentially higher toxic effects.

Pollution characteristics and health risk assessment of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons during heating season in Beijing

Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (NPAHs) attract continuous attention due to their outstanding carcinogenicity and mutagenicity. In order to investigate the diurnal variations, sources, formation mechanism, and health risk assessment of them in heating season, particulate matter (PM) were collected in Beijing urban area from December 26, 2017 to January 17, 2018. PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry (GC-MS) . Average daily concentrations of PAHs and NPAHs were (78 ± 54) ng/m³ and (783 ± 684) pg/m³, respectively. The concentrations of them were significantly higher at nighttime than at daytime, and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations. In the heating season, the dominant species of PAHs include benzo[b]fluoranthene, fluoranthene, pyrene, and chrysene, while 9-nitroanthracene, 2+3-nitrofluoranthene, and 2-nitropyrene were dominant species for NPAHs. NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7 µm particle size. Primary emissions such as biomass burning, coal combustion, and traffic emissions were the major sources of PAHs. NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals, as well as biomass burning during daytime. According to the health risk assessment, the total carcinogenic risk was higher in adults than in children. While upon oral ingestion, the carcinogenic risk in children was higher than that of adults, but the risk of adults was higher than children through skin contact and respiratory inhalation.

Effect of photooxidation on size distribution, light absorption, and molecular compositions of smoke particles from rice straw combustion

Organic aerosol (OA) emitted from biomass burning (BB) impacts air quality and global radiation balance. However, the comprehensive characterization of OA remains poorly understood because of the complex evolutionary behavior of OA in atmospheric processes. In this work, smoke particles were generated from rice straw combustion. The effect of OH radicals photooxidation on size distribution, light absorption, and molecular compositions of smoke particles was systematically investigated. The results showed that the median diameters of smoke particles increased by a factor of approximately 1.2 after photooxidation. In the particle compositions, although both non-polar fractions (n-hexane-soluble organic carbon, HSOC) and polar fractions (water-soluble organic carbon, WSOC) underwent photobleaching after aging, the photobleaching properties of HSOC (1.87-2.19) was always higher than that of WSOC (1.52-1.33). Besides, the light-absorbing properties of HSOC were higher than that of WSOC, showing a factor of approximately 1.75 times for mass absorption efficiency at 365 nm (MAE₃₆₅). Consequently, the simple forcing efficiency (SFE) caused by absorption showed that HSOC has higher radiation effects than WSOC. After photooxidation, the concentration of 16 PAHs in HSOC fractions significantly decreased by 15.3%-72.5%. In WSOC fractions, the content of CHO, CHONS, and CHOS compounds decreased slightly, while the content of CHON compounds increased. Meantime, the variations in molecular properties supported the decrease in light absorption of WSOC fractions. These results reveal the aging behavior of smoke particles, then stress the importance of non-polar organic fractions in particles, providing new insights into understanding the atmospheric pollution caused by BB smoke particles.

Assessment of the temporal variability and health risk of atmospheric particle-phase polycyclic aromatic hydrocarbons in a northeastern city in China

In this study, we examined the sources and temporal variability of 16 polycyclic aromatic hydrocarbons (PAHs) found in fine particulate matter (PM_2.5) in a typical industrial city in northern China. We also evaluated the incremental lifetime cancer risk (ILCR) from the inhalation of these PAHs. Atmospheric PM_2.5 samples were collected for 7 consecutive days each month from 2014 to 2019, and the 16 PAHs were measured using multiplex gas chromatography-tandem mass spectrometry. The carcinogenic risk of PAH exposure was assessed using the inhalation unit risk (IUR) and cancer slope factor (CSF) methods. The annual average concentrations of PM_2.5 for each year from 2014 to 2019 were 102.87±55.25, 86.92±60.43, 69.17±37.74, 58.20±59.15, 56.01±34.52, and 52.54±58.15 µg m^-3, and the annual average ΣPAH concentrations were 56.03±81.09, 47.99±79.30, 40.41±57.31, 33.57±51.79, 43.23±74.80, and 25.20±50.91 ng m^-3, respectively. Source identification, using diagnostic ratio analysis, indicated that the major PAH sources were coal/biomass combustion, fuel combustion, and traffic emissions. A health risk assessment showed that the ILCR from PAH inhalation decreased throughout the study period and varied with age. The IUR and CSF methods both showed that the adult ILCR exceeded 1.0×10^-6. These findings demonstrate the importance of addressing the carcinogenic risk of PM_2.5-bound PAHs, particularly in adults.

Temporal profiles, source analysis, and health risk assessments of parent polycyclic aromatic hydrocarbons (PPAHs) and their derivatives (NPAHs, OPAHs, ClPAHs, and BrPAHs) in PM2.5 and PM1.0 from the eastern coastal region of China: Urban coastal area versus coastal background area

The eastern coastal region of China is the area with the highest emission of PAHs in China. Therefore, understanding the sources and health risk of parent polycyclic aromatic hydrocarbons (PPAHs) and their derivatives in eastern coastal cities of China is the main basis for air pollution control. In this study, we measured the concentrations of 18 parent PAHs, 17 nitrated PAHs, 7 oxygenated PAHs, 8 chlorinated PAHs, and 13 brominated PAHs in PM_1.0 and PM_2.5 samples collected at an urban coastal city site and a coastal background site in 2019. We analyzed the temporal distribution, molecular composition, and sources and performed health risk assessments for both winter and summer samples. The average concentration of the PPAHs and their derivatives (all 63 compounds combined) in the PM_1.0 samples accounted for 75.57% of the PAHs concentration in PM_2.5 samples. The average concentration of PM_2.5- and PM_1.0- bound PPAHs in winter was 114.70 times higher than in summer, and their derivatives was 27.51 times. Both the combined concentrations of the 18 PPAHs and the combined concentrations of the 45 derivatives were higher in the coastal city compared to the background site during the winter (1.90 and 1.48 times, respectively), but they were comparable during the summer. The positive matrix factorization analysis indicated that the compounds mainly originated from coal/biomass combustion, industrial sources, vehicle emissions, and secondary formation. In addition, the concentration-weighted trajectories model revealed that the PAHs were mainly emitted locally in Shandong Province and surrounding areas, such as Hebei Province, Henan Province, and Bohai Sea. The compounds 1-NPYR, 2+9-BrPHE, 9,10-Cl2PHE, and 1-ClPYR dominantly contributed to the derivatives of TEQ during the winter due to their high concentrations or the high TEFs of these compounds.

Determination of tipping point in course of PM2.5 organic extracts-induced malignant transformation by dynamic network biomarkers

The dynamic network biomarkers (DNBs) are designed to identify the tipping point and specific molecules in initiation of PM_2.5-induced lung cancers. To discover early-warning signals, we analyzed time-series gene expression datasets over a course of PM_2.5 organic extraction-induced human bronchial epithelial (HBE) cell transformation (0^th~16^th week). A composition index of DNB (CI_DNB) was calculated to determine correlations and fluctuations in molecule clusters at each timepoint. We identified a group of genes with the highest CI_DNB at the 10^th week, implicating a tipping point and corresponding DNBs. Functional experiments revealed that manipulating respective DNB genes at the tipping point led to remarkable changes in malignant phenotypes, including four promoters (GAB2, NCF1, MMP25, LAPTM5) and three suppressors (BATF2, DOK3, DAP3). Notably, co-altered expression of seven core DNB genes resulted in an enhanced activity of malignant transformation compared to effects of single-gene manipulation. Perturbation of pathways (EMT, HMGB1, STAT3, NF-κB, PTEN) appeared in HBE cells at the tipping point. The core DNB genes were involved in regulating lung cancer cell growth and associated with poor survival, indicating their synergistic effects in initiation and development of lung cancers. These findings provided novel insights into the mechanism of dynamic networks attributable to PM_2.5-induced cell transformation.

The PM2.5-bound polycyclic aromatic hydrocarbon behavior in indoor and outdoor environments, part II: Explainable prediction of benzo[a]pyrene levels

Among the polycyclic aromatic hydrocarbons (PAH), benzo[a]pyrene (B[a]P) has been considered more relevant than other species when estimating the potential exposure-related health effects and has been recognized as a marker of carcinogenic potency of air pollutant mixture. The current understanding of the factors which govern non-linear behavior of B[a]P and associated pollutants and environmental processes is insufficient and further research has to rely on the advanced analytical approach which averts the assumptions and avoids simplifications required by linear modeling methods. For the purpose of this study, we employed eXtreme Gradient Boosting (XGBoost), SHapley Additive exPlanations (SHAP) attribution method, and SHAP value fuzzy clustering to investigate the concentrations of inorganic gaseous pollutants, radon, PM_2.5 and particle constituents including trace metals, ions, 16 US EPA priority PM_2.5-bound PAHs and 31 meteorological variables, as key factors which shape indoor and outdoor PM_2.5-bound B[a]P distribution in a university building located in the urban area of Belgrade (Serbia). According to the results, the indoor and outdoor B[a]P levels were shown to be highly correlated and mostly influenced by the concentrations of Chry, B[b]F, CO, B[a]A, I[cd]P, B[k]F, Flt, D[ah]A, Pyr, B[ghi]P, Cr, As, and PM_2.5 in both indoor and outdoor environments. Besides, high B[a]P concentration events were recorded during the periods of low ambient temperature (<12 °C), unstable weather conditions with precipitation and increased soil humidity.

Investigation of Indoor Polycyclic Aromatic Hydrocarbons (PAHs) in Rural Northeast China: Pollution Characteristics, Source Analysis, and Health Assessment

Due to the low winter temperatures in rural areas of Northeast China, biomass fuels are widely used for heating and cooking, resulting in increased concentrations of PAHs in rural indoor areas during the heating period and threatening human health. Therefore, exploring the pollution characteristics, source localization, and risk assessment of indoor PAHs in rural Northeast China is of great significance for improving rural indoor air quality. In this study, PAHs were collected from a residential building in rural Northeast China for one consecutive year (January 2020–December 2020), and their concentrations were determined to explore the distribution patterns and sources of PAHs to further assess the carcinogenic risk of PAHs to humans. The results of the study showed that the average concentration of indoor PAHs in rural areas during the heating period (93.02 ng/m3) was about 1.81 times higher than that of the non-heating period (51.26 ng/m3). The main sources of PAHs were mixed combustion of biomass and coal, motor vehicle emissions, and domestic waste combustion. The level of indoor PAHs pollution has posed a carcinogenic risk to the health of the rural population in the Northeast.

Molecular characterization of organic aerosols in Taiyuan, China: Seasonal variation and source identification

Fine particulate matter (PM_2.5) samples collected in 2018 in Taiyuan, a typical industrial and mining city in North China Plain (NCP), were characterized based on ultrahigh-performance liquid chromatography (UHPLC) coupled with orbitrap mass spectrometry. Potential molecular identifications based on precise molecular weight were conducted to obtain the compositional and source information of organic aerosols (OAs) in this city. Evident variation trends were observed during the sampling period in the composition, degree of oxidation and saturation of the obtained molecules. The proportion of CHOS- and CHO+ were increased from winter to summer and then decreased, conversely the proportion of CHN+ was decreased from winter to summer and then increased. By reclassifying the molecules, OA molecules were observed to be more saturated and oxidized in summer. It was caused by the high abundance of organosulfates (OSs) in summer, and aromatic amines/N-heterocycle aromatic hydrocarbons (PANHs) in winter. Molecular identification indicated that the OSs were basically originated from biogenic source isoprene or monoterpene, while the aromatic amines and PANHs were related to anthropogenic emissions of fossil fuel combustion, like other cities in the NCP area. The prevailing northwesterlies in winter may bring coal-burning pollutants from other cities, while the high abundance of organosulfates in summer may be related to the PM_2.5 transportation from Shijiazhuang. This study firstly demonstrates the molecular composition characteristics, potential sources, and geographical origins of PM_2.5 in Taiyuan, which gives a comprehensive understanding of PM_2.5 in a typical industrial and mining city.

Particle-bound PAHs induced glucose metabolism disorders through HIF-1 pathway

Vehicle exhaust, as one of the most important compositions of air pollution, induced various adverse health effects, especially diabetes, on human beings. Even though monitoring and epidemiological data indicates that particle-bound polycyclic aromatic hydrocarbons (PAHs) is an inducing factor of diabetes, the specific causative mechanisms are still unclear. In the current study, the concentration of particulate matters (PMs, including PM_1.0, PM_2.5 and PM_10.0) and PAHs was investigated at rush hour of weekday in three urban underground parking garages (UPGs). To evaluate the impacts of particle-bound PAHs on human beings, analysis of non-target metabolomics and unmetabolized PAHs were conducted for UPG and non-UPG worker urine samples. The results showed that the highest concentrations of PMs and total PAHs were found at the UPG entrance. The concentrations of unmetabolized 5-6 rings PAHs in the UPG worker urine were significantly higher than that in non-UPG worker urine samples, which induced glucose metabolism disorders through hypoxia-inducible factor 1 (HIF-1) signaling pathway. This could be a reason for particle-bound PAHs induced-diabetes on road workers, drivers and garage staff. These findings can serve as a step towards air pollution management and the pathological mechanism analysis of environmental factor induced-diseases.

Assessment of pollution by the combustion residue and smoke of boron blended flash powder

Possible environmental effects of flash powder mixture combustion containing aluminium and boron along with other ingredients like potassium nitrate and sulphur are reported. Once the firecrackers are lighted, they burst out particulate matter and harmful gases with scintillating effect. These particulate matters and the harmful gases together make the environment fogged and get deposited on all surfaces. Recent research suggests replacing aluminium with boron to implement safety during manufacturing and to enhance performance. But the effects of the combustion residue have to be checked and compared before implementation. Hence, in this work, the possible effects of the firework mixtures particularly flash powder mixtures containing aluminium are monitored and compared with the effects of boron blended flash powder mixtures. Based on the smoke settling test, plant growth test and soil test, it is concluded that up to 12.5% of boron can be added in flash powder mixture to prevent pollution of the environment. The threshold quantity of residue without affecting the soil quality for 100 % usage of boron was found as 10 g of residue in 2 kg of soil.

A review on analysis methods, source identification, and cancer risk evaluation of atmospheric polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) have gained attention because of their environmental persistence and effects on ecosystems, animals, and human health. They are mutagenic, carcinogenic, and teratogenic. The review provides background knowledge about their sources, metabolism, temporal variations, and size distribution in atmospheric particulate matter. The review article briefly discusses the analytical methods suitable for the extraction, characterization, and quantification of nonpolar and polar PAHs, addressing the challenges. Herein, we discussed the molecular diagnostic ratios (DRs), stable carbon isotopic analysis (SCIA), and receptor models, with much emphasis on the positive matrix factorization (PMF) model, for apportioning PAH sources. Among which, DRs and PCA identified as the most widely employed method, but their accuracy for PAH source identification has received global criticism. Therefore, the review recommends compound-specific isotopic analysis (CSIA) and PMF as the best alternative methods to provide detailed qualitative and quantitative source analysis. The compound-specific isotopic signatures are not affected by environmental degradation and are considered promising for apportioning PAH sources. However, isotopic fractions of co-eluted compounds like polar PAHs and aliphatic hydrocarbons make the PAHs isotopic fractions interpretation difficult. The interference of unresolved complex mixtures is a limitation to the application of CSIA for PAH source apportionment. Hence, for CSIA to further support PAH source apportionment, fast and cost-effective purification techniques with no isotopic fractionation effects are highly desirable. The present review explains the concept of stable carbon isotopic analysis (SCIA) relevant to PAH source analysis, identifying the techniques suitable for sample extract purification. We demonstrate how the source apportioned PAHs can be applied in assessing the health risk of PAHs using the incremental lifetime cancer risk (ILCR) model, and in doing so, we identify the key factors that could undermine the accuracy of the ILCR and research gaps that need further investigation.

The effect of air pollution on immunological, antioxidative and hematological parameters, and body condition of Eurasian tree sparrows

Air pollution constitutes potential threats to wildlife and human health; therefore, it must be monitored accurately. However, little attention has been given to understanding the toxicological effects induced by air pollution and the suitability of bird species as bioindicators. The Eurasian tree sparrow (Passer montanus), a human commensal species, was used as a study model to examine toxic metal accumulation, retention of particulate matter (PM), immunological and antioxidant capacities, and hematological parameters in birds inhabiting those areas with relatively higher (Shijiazhuang city) or lower (Chengde city) levels of PM_2.5 and PM₁₀ in China. Our results showed that Shijiazhuang birds had significantly more particle retention in the lungs and toxic metal (including aluminum, arsenic, cadmium, iron, manganese, and lead) accumulation in the feathers relative to Chengde birds. They also had lower superoxide dismutase, albumin, immunoglobulin M concentrations in the lung lavage fluid, and total antioxidant capacity (T-AOC) in the lungs and hearts. Furthermore, although they had higher proportions of microcytes, hypochromia, and polychromatic erythrocytes in the peripheral blood (a symptom of anemia), both populations exhibited comparable body conditions, white cell counts, heterophil and lymphocyte ratios, and plasma T-AOC and corticosterone levels. Therefore, our results not only confirmed that Shijiazhuang birds experienced a greater burden from environmental PM and toxic metals but also identified a suite of adverse effects of environmental pollution on immunological, antioxidative, and hematological parameters in multiple tissues. These findings contribute to our understanding of the physiological health consequences induced by PM exposure in wild animals. They suggest that free-living birds inhabiting urban areas could be used as bioindicators for evaluating the adverse effects induced by environmental pollution.

Impacts of Independence Day fireworks on pollution levels of atmospheric polycyclic aromatic hydrocarbons (PAHs) in the U.S

Fireworks on Independence Day have been identified as a nationwide but short-term source of particulate matter in the U.S. No study has specifically examined their impacts on ambient polycyclic aromatic hydrocarbons (PAHs). Based on data between 1990 and 2019 in the Air Quality System, we identified 76 unique events that had PAH measurements on both July 4th days and control days (within 15 days before and after July 4th). We compared concentrations and diagnostic ratios of 16 priority PAHs between event and control days using Wilcoxon signed-rank tests and multivariable regressions. A local PAH monitoring campaign was conducted at eight sites in Memphis, Tennessee, to obtain a close observation of PAH changes. The national geometric mean (GM) concentrations of summed 16 PAHs (ΣPAHs) were similar between event and control days (48.1 ng/m³ vs. 52.8 ng/m³, p = 0.98). About a quarter of events had elevated PAH concentrations compared with control days. Higher diagnostic ratios were found on event days, suggesting more contributions from fireworks sources. PAHs on July 4th were unlikely to cause acute or chronic health effects. While the local monitoring showed a 15% increase of ΣPAHs on July 4th, the difference was not significant (p = 0.62). Elevated PAH concentrations occurred at sites near fireworks sources and without major traffics, but did not occur at those in remote areas or near major interstate highways. In conclusion, this study finds that Independence Day fireworks have negligible impacts on atmospheric PAHs at the national level, and are unlikely to pose significant health risks. The firework effect is localized within a limited geographic scale, suggesting potential needs for local monitoring and control programs.

Atmospheric concentration, source identification, and health risk assessment of persistent organic pollutants (POPs) in two countries: Peru and Turkey

It is known that some persistent organic pollutants (POPs) are used worldwide, and these pollutants are dangerous for human health. However, there are still countries where measurements of these pollutants have not been adequately measured. Although many studies have been published for determining the concentrations of POPs in Turkey, there are limited studies in Latin American countries like Peru. For this reason, it is essential both to conduct a study in Peru and to compare the study with another country. This study is aimed at determining the atmospheric POPs such as polycyclic aromatic hydrocarbon (PAH), organochlorine pesticide (OCP), and polychlorinated biphenyl (PCB) concentrations using passive air samplers in Yurimaguas (Peru) and Bursa (Turkey). Molecular diagnosis ratios and ring distribution methods were used to determine the sources of PAHs. According to these methods, coal and biomass combustions were among the primary sources of PAHs in Peru, while petrogenic and petroleum were the primary sources of PAHs in Turkey. Then, α-HCH/γ-HCH and β-/(α+γ)-HCH ratios were used to determine the sources of OCPs. According to the α-HCH/γ-HCH ratios, the primary sources of OCPs in both countries were lindane. Similarly, according to β-/(α+γ)-HCH ratios, the HCHs have been historically used in Peru while they were recently utilized in Turkey. Finally, homologous group distributions were used to determine the sources of PCBs. Similar distributions of homologous groups were observed in the sampling sites in both countries. Also, the homologous group distributions obtained have been determined that industrial activities could be effective in the sampling areas in both countries. When the cancer risks that could occur via inhalation were evaluated, no significant cancer risk has been determined in both countries.

Polycyclic aromatic hydrocarbons in leaves of Cinnamomum camphora along the urban-rural gradient of a megacity: Distribution varies in concentration and potential toxicity

Rapid urbanization and industrialization have precipitated the significant urban-rural gradient involving various aspects of human-related activities especially in megacities. Anthropogenic activities are the main source of polycyclic aromatic hydrocarbon (PAH) contamination, and the rising awareness concerning PAH potential toxicity to human health promotes a further understanding of its spatial distribution pattern in cities. Whether the distribution of PAH concentration and potential toxicity respond to the urban-rural gradient still requires investigation. This study applied a grid sampling method to investigate PAH concentration using Cinnamomum camphora leaves as bioindicators which were obtained from 84 sampling sites in a megacity, Shanghai. The potential toxicity of PAHs in leaves was calculated by toxicity factor equivalent method. Results revealed the patterns of PAH distribution in the city varied in concentration and potential toxicity: the total concentration of PAHs in leaves decreased along the urban-rural gradient, while the potential toxicity peaked at junction areas. The trend of PAH concentration along the distance from urban center corresponded to that of population density. The spatial distribution of potential toxicity did not correspond with the gradient but was influenced by high benzo(a)pyrene concentration originated from the industry districts nearby. Higher potential toxicity of PAHs was observed at the urban-suburban-rural junction areas of megacities, advocating health-risk attention and appropriate plan for land use of these transition areas in cities.

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and nitrated-PAHs (NPAHs) emitted by gasoline vehicles: Characterization and health risk assessment

Seventeen polycyclic aromatic hydrocarbons (PAHs) and eight nitrated PAHs (NPAHs) in PM_2.5 and conventional gaseous pollutants exhausted from 54 in-use gasoline vehicles encompassing different emission standards (China 1 to China 5) were tested on the chassis and engine dynamometric test bench. With the increase of emission standards, a decrease in the emissions of PM_2.5-bound PAHs and NPAHs was detected. The emission factors (EFs) of total PAHs and NPAHs in PM_2.5 emitted by the vehicles with a mileage of >100,000 km were greater than that emitted by the vehicles with driving mileage of <100,000 km under all the five emission standards. The EFs of PM_2.5-bound PAHs and NPAHs emitted from port fuel injection engines were larger than that from gasoline direct injection engines. The emissions of PM_2.5-bound PAHs and NPAHs were less correlated with the exhaust of CO, while the hydrocarbon (HC) emissions were strongly correlated with the PM_2.5-bound PAHs emissions. The emissions of NPAHs and NOx had an inverse correlation. The toxic (TEQs) of total PAHs and NPAHs in China 3, China 4 and China 5 were significantly reduced compared to China 1 and China 2, which may be related to exhaust technology improvements. Although the EFs of NPAHs were significantly lower than those of PAHs, the TEQs of NPAHs were higher, which indicates that the toxic effect of NPAHs emitted by gasoline vehicles were stronger than PAHs.

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and their derivatives (nitrated-PAHs and oxygenated-PAHs) in a road tunnel located in Qingdao, China: Characteristics, sources and emission factors

Daytime and nighttime PM_2.5 samples were collected at a road tunnel located in Qingdao, China. The mass concentrations and chemical compositions of polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (NPAHs) and oxygenated-PAHs (OPAHs) were analysed to determine the variation characteristics and sources. The concentrations in exit were obviously higher than those of entrance in the tunnel. Fluoranthene (FLT) and Pyrene (PYR) were the most abundant PAHs, 2 + 3-nitrofluoranthene (2 + 3N-FLA), 1-nitropyrene (1N-PYR) and 2-nitropyrene (2N-PYR) were the dominant NPAHs, and 9-fluorenone (9-FO) and 9,10-anthraquinone (9,10-ANQ) were the most abundant OPAHs. The high rings (4-6 rings) PAHs accounted for over 90% of the total PM_2.5-bound PAH concentrations, most of which were considered as motor vehicle emissions. Based on the diagnostics ratios and PCA results, the most important sources of PAHs and NPAHs were estimated as gasoline and diesel vehicles emissions in the tunnel. In addition, non-exhausts (such as road dust, brake line, asphalt and tires wear) also had some contributions to PAHs and NPAHs. The average emission factors were 60.98, 9.02 and 8.47 μg veh^-1 km^-1 for total PM_2.5-bound PAHs, NPAHs and OPAHs, respectively. The emission factors of high rings (4-6 rings) PAHs were greater than those with low rings (2-3 rings). 1N-PYR had the highest emission factor in all measured NPAHs, while the emission factors for the two highest OPAHs were 9-FO and 9,10-ANQ in this tunnel.

Remediation of 1-Nitropyrene in Soil: A Comparative Study with Pyrene

Nitrated polycyclic aromatic hydrocarbons (nPAHs) are ubiquitous environmental pollutants, which exhibits higher toxicity than their corresponding parent PAHs (pPAHs). Recent studies demonstrated that the nPAHs could represent major soil pollution, however the remediation of nPAHs has been rarely reported. In this study, biological, physical, and chemical methods have been applied to remove 1-nitropyrene, the model nPAH, in contaminated soil. A comparative study with pyrene has also been investigated and evaluated. The results suggest that the physical method with activated carbon is an efficient and economical approach, removing 88.1% and 78.0% of 1-nitropyrene and pyrene respectively, within one day. The zero-valent ion has a similar removal performance on 1-nitropyrene (83.1%), converting 1-nitropyrene to 1-aminopyrene in soil via chemical reduction and decreasing the mutagenicity and carcinogenicity of 1-nitropyrene. Biological remediation that employs scallion as a plant model can reduce 55.0% of 1-nitropyrene in soil (from 39.6 to 17.8 μg/kg), while 77.9% of pyrene can be removed by plant. This indicates that nPAHs might be more persistent than corresponding pPAHs in soil. It is anticipated that this study could draw public awareness of nitro-derivatives of pPAHs and provide remediation technologies of carcinogenic nPAHs in soil.

PAH levels in a furniture-manufacturing city atmosphere

In this study, in order to determine atmospheric PAH concentrations in Inegol/Turkey, ambient air samples were collected from two different sites representing industrial and uncontrolled furniture manufacturers regions. Sampling campaign took place between December 2017 and November 2018. Air samples were collected using high volume air samplers (HVAS) and PAH concentrations were determined in both gas and particulate phases. The mean of the atmospheric PAH concentrations obtained in the gas phase in the furniture workshops (FW) and industrial district (ID) regions were 697.82 ± 637 ng/m³ and 772.92 ± 864.23 ng/m³, respectively. The concentrations in the particulate phase in the regions were 413.52 ± 430.23 ng/m³ and 342.40 ± 527.48 ng/m³, respectively. The average total (gas + particlulate phases) concentration of ∑₁₆PAH determined in the site of FW was 1111.34 ± 1045.24 ng/m³ while that was 772.92 ± 864.23 ng/m³ in ID. These values are over the ambient levels reported for urban sites wherein big industries exist around the world. Additionally, the average of particle phase percentage was 30% because of nearby combustion sources. The determination of possible sources of PAHs in the regions was performed using principal component analysis (PCA). PCA results showed that the main sources of pollutants of the regions are intertwined (combustion, traffic, industries). However, the most effective source is thought to be uncontrolled combustion of furniture wastes as fuel for residential heating. Health risks for the citizens were calculated for both regions and were found not to be at high-class risk.