Exploration and comparison of the relationship between PAHs and ROS in PM2.5 emitted from multiple anthropogenic sources in the Guanzhong Plain, China.

Anthropogenic emissions have emerged as an important source of urban atmospheric PM2.5, exacerbating air pollution and the associated health implications. This study analyses PM2.5, originating from major anthropogenic sources (industries, motor vehicles, and solid-fuel combustion for domestic applications) in the Guanzhong Plain in China, along with the parent- (p-), alkylated- (a-), and oxygenated- (o-) polycyclic aromatic hydrocarbons (PAHs) and reactive oxygen species (ROS) levels in PM2.5. Industrial emissions are mainly characterised by high abundances of benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), and benz[a]fluoranthene (BaF). The 4-ring p-PAHs, such as fluoranthene (FLA), pyrene (PYR), benzo[a]anthracene (BaA), and chrysene (CHR) proportions and the diagnostic ratios of indeno[1,2,3-cd]pyrene (IcdP)/[IcdP + benzo[ghi]perylene (BghiP)] and 1-acenaphthenone (1ACO)/[1ACO + 9-fluorenone (9FO)] in motor vehicle emission PM2.5 were higher than the other sources. Household solid fuel combustion features high proportions of methylnaphthalene (M-NAP), i.e., 2 M-NAP and 1 M-NAP and 3-ring p-PAHs. Acenaphthylene (ACY), acenaphthene (ACE), anthracene (ANT), 1,4-chrysenequinone (1,4CHRQ), and reactive oxygen species (ROS) were positively correlated among the three anthropogenic sources. Moreover, the correlations between other PAHs and ROS varied significantly among the three sources. As mixed and compound organic pollutants, 2- and 3-ring p-PAHs were more positively correlated with the ROS activity of household solid fuel combustion sources compared with industrial and motor vehicle sources. Based on the relative contribution of these three sources to PAHs in PM2.5, we estimated the cancer risks of males and females in the Guanzhong area to be 2.95 × 10-6 and 2.87 × 10-6, respectively, exceeding the safety threshold of 1 × 10-6. This study provides a basic dataset for conducting a refined source apportionment of PM2.5 and a scientific basis for further understanding the relationship between PM2.5, PAHs, and ROS in northern China.

Insight into personal exposure characteristics and health effects of PM2.5 and PM0.25-bound PAHs and their derivatives with different heating ways in the Fenwei Plain, China.

Personal exposure (PE) to polycyclic aromatic hydrocarbons (PAHs) and their derivatives in particulate matter with two aerodynamic sizes of 2.5 and 0.25 µm (PM2.5 and PM0.25) from rural housewives was studied in the Fenwei Plain, China. A total of 15 households were divided into five different groups based on the type of solid fuel and heating device used, including biomass briquette-furnace (BBF), biomass-elevated Kang (BEK), outdoor lump coal-boiler (OLC), indoor briquette coal-stove (IBC), and electricity (ELE). The PE concentrations of the PAHs and biomarkers in urine collected from the participants were determined. The results showed that the PE concentrations of total quantified PAHs in the biomass group (i.e., BBF and BEK) were 2.2 and 2.0 times higher than those in the coal groups (i.e., OLC and IBC) in PM2.5 and PM0.25, respectively. The housewives who used biomass as fuel suffered from higher potential health impacts than the coal fuel users. The incremental lifetime cancer risk for the PAHs in PM2.5 in the BBF and BEK groups exceeded the international safety threshold. Furthermore, the PE concentrations of oxygenated PAH (o-PAHs) in PM2.5 and PM0.25 in the biomass groups and the nitrated PAHs (n-PAHs) in PM0.25 in the coal groups showed strong correlations with the biomarkers. The results of this study proved the associations between exposure to the different classes of PAHs and health hazards. The findings could also serve as a guideline in establishing efficient measures for using solid fuels for cooking and household warming in northern China.

Chemical composition and potential health risks of tire and road wear microplastics from light-duty vehicles in an urban tunnel in China.

Tire and road wear microplastics (TRWMPs) are one of the main non-exhaust pollutants of motor vehicles, which cause serious environmental and health issues. Here, TRWMPs in PM2.5 samples were collected in a tunnel in urban Xi'an, northwest China, during four periods [I: 7:30-10:30, II: 11:00-14:00, III: 16:30-19:30, IV: 20:00-23:00 local standard time (LST)] in summer of 2019. The chemical components of rubbers, benzothiazoles, phthalates, and amines in TRWMPs were quantified, with a total concentration of 6522 ± 1455 ng m-3 (mean ± standard deviation). Phthalates were predominant in TRWMPs, accounting for 64.8% on average, followed by rubbers (33.2%) and benzothiazoles (1.19%). The diurnal variations of TRWMPs showed the highest concentration in Period III (evening rush hour) and the lowest concentration in Period I (morning rush hour), which were not exactly consistent with the variation of the number of light-duty vehicles passed through the tunnel. The result implied that the number of vehicles might not be the most important contributor to TRWMPs concentration, whereas meteorological variables (i.e., precipitation, and relative humidity), vehicle speed, vehicle class, and road cleaning also affected their abundances. The non-carcinogenic risk of TRWMPs in this study was within the international safety threshold, but their carcinogenic risk exceeded the threshold by 2.7-4.6 times, mostly dominated by bis(2-ethylhexyl)phthalate (DEHP). This study provides a new basis for the source apportionment of urban PM2.5 in China. The high concentrations and high potential cancer risks of TRWMPs represent the requirement for more efficient measures to control light-duty vehicle emissions.

Environmental and health impacts of household energy conversion on PAHs and their derivatives in PM2.5 in typical areas of northern China.

Heavy use of solid fuels in rural households of northern China emits huge amounts of fine particulate matter (i.e., PM2.5) that pose notable indoor air pollution and severe inhalation health risks. In this study, the environmental and health benefits of clean energy substitution were accessed by monitoring indoor and personal exposure to polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and pulmonary function and biological parameters. After substitutions of traditional lump coal and biomass fuels by clean coal, indoor concentrations of parent PAHs (p-PAHs), alkylated PAHs (a-PAHs), oxygenated PAHs (o-PAHs), and nitro PAHs (n-PAHs) reduced by 71 %, 32 %, 70 %, and 76 %, while personal exposure concentrations decreased by 82 %, 87 %, 93 %, and 86 %, respectively. However, the proportion of low molecular weight PAHs increases, especially for 2-ring a-PAHs and 3-ring n-PAHs. Domestic solid fuel burning induces greater damage to the small airway than the large airway. Pulmonary function parameter reductions in the clean coal group are much less than those in the other two fuel groups. Salivary interleukin-6 (IL-6) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) significantly correlated with PAH species, among which p-PAHs and PAHs derivatives strongly with IL-6 and 8-OHdG, respectively. The correlation between PAHs and biomarkers in urine is insignificant. In addition, the use of clean coal can reduce the cancer risk for the four classes of PAHs by 60 %-97 %, mainly owing to the lower contributions from p-PAHs and o-PAHs. The result of the study provides scientific support for clean energy retrofit and an understanding of health benefits from solid fuel substitutions.

Associations of personal exposure to domestic heating and cooking fuel emissions and epidemiological effects on rural residents in the Fenwei Plain, China.

Solid fuel combustion for domestic heating in northern China in the wintertime is of great environmental and health concern. This study assesses personal exposure to particulate matter with different aerodynamic diameters and multiple gaseous pollutants from 123 rural residents in Yuncheng, the Fenwei Plain. The subjects are divided into groups based on the unique energy source applied, including biomass, coal, and electricity/no heating activities. The health effects of the exposures are expressed with four urinary biomarkers. The personal exposure levels to three different aerodynamic particle sizes (i.e., PM10, PM2.5, and PM1) of the electricity/no heating group are 5.1 % -12 % lower than those of the coal group. In addition, the exposure levels are 25 %-40 % lower for carbon monoxide (CO) and 10.8 %-20.3 % lower for ozone (O3) in the electricity/no heating group than the other two fuel groups. C-reactive protein (CRP) in the urine of the participants in biomass and coal groups is significantly higher than that in the electricity/no heating group, consistent with the observations on other biomarkers. Increases in 8-hydroxy-2 deoxyguanosine (8-OHdG), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) are observed for the exposures to higher concentrations of air pollutants. For instance, PMs and nitrogen dioxide (NO2) show significant impacts on positive correlations with 8-OHdG and IL-8, while O3 positively correlates with CRP. PM1 exhibits higher effects on the biomarkers than the gaseous pollutants, especially on VEGF and IL-8. The study indicates that excessive use of traditional domestic solid fuels could pose severe health effects on rural residents. The promotion of using clean energy is urgently needed in the rural areas of northern China.

Chemical characterization of PM2.5 in heavy polluted industrial zones in the Guanzhong Plain, northwest China: Determination of fingerprint source profiles.

Industrial emission has been proved to be an important source of atmospheric PM2.5, which causes serious air pollution and health impacts. The air quality of the industrial zones, which are the intermediate stationary areas between the direct emissions and diffusion to the atmosphere, is always overlooked. In this study, the PM2.5 filter samples were collected in the six representative types of industrial zones in four cities of the Guanzhong Plain in 2020. The chemical characteristics of fine particulate matter (PM2.5) in the zones were investigated. The mass concentrations of 13 elements and 39 polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were quantified. Cement and concrete (CC) and brick production (BP) exhibited a similar chemical composition profile characterized by high proportions of calcium (Ca), aluminum (Al), benzo[k]fluoranthene (BkF), 1-nitronaphthalene (1N-NAP), and 3-nitrofluoranthene (3N-FLA). Glassware and ceramics (GC) showed a distinguishable profile with a relatively low ratio of copper/cadmium (Cu/Cd) and lead (Pb)/Cd. The profile for metal forging (MF) was abundant in vanadium (V), Pb, indeno[1,2,3-cd]pyrene (IcdP) and also recognized by particular diagnostic ratios of nitrated-PAHs (n-PAHs). The highest proportions of several metals such as chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), zinc (Zn), Cd, and fluoranthene (FLA) were found in the thermoelectric industry (TI) due to a large amount of coal consumption in the manufacture processing. Chemical production (CP) was the only industrial type using natural gas as the main fuel in this study, which shows the distinguishing feature of relatively high proportions of low molecular weight parent-PAHs (p-PAHs) and 2-ring oxygenated-PAHs (o-PAHs). This study not only attains the detailed chemical fingerprints, but also the potential tracers and ratios, which are of great significance for refining source apportionment and relieving PM2.5 pollution contributed by the industrial sources.

Variations of Personal Exposure to Particulate Nitrated Phenols from Heating Energy Renovation in China: The First Assessment on Associated Toxicological Impacts with Particle Size Distributions.

The clean heating renovation has been executed for improving particulate matter (PM) pollution in northern China since 2017. This study determined particle size distributions of nitrated phenols (NPs) in personal exposure samples and their associations with biomarkers in saliva and urine from homemakers in rural households of the Fenwei Plain, China. Remarkable reductions of 28.6-66.3% and 52.2-82.4% on PMs and total quantified NPs, respectively, were found with the substitutions of raw coal chunk and biomass by advanced clean coal. 4-Nitroguaiacol (4NG) showed the largest reductions of 81.2% among individual NP. In addition, the clean coal efficiently reduced interleukin-6 (IL-6) and 8-hydrox-2'-deoxyguanosine (8-OHdG) in the urine and saliva by 12-72%. Furthermore, significant positive correlations between urinary 8-OHdG with most of NPs in all particle sizes, urinary IL-6 with 4NG for particles with Dp > 2.5 µm and Dp = 0.25-1.0 µm and salivary IL-6 with 4-nitrocatechol and 4-methyl-5-nitrocatechol for particles with Dp > 2.5 µm, Dp = 0.5-1.0 µm, and Dp < 0.25 µm were observed but not for salivary 8-OHdG or PMs. The results provide scientific support for the clean energy reformation and demonstrate the strong particle size dependence between NPs and biomarkers.