Characteristics and health risk assessment of indoor and outdoor PM_2.5 in a rural village, in Northeast of China: impact of coal and biomass burning

Fine particulate matter (PM_2.5) has health effects that may depend on its sources and chemical composition. In this study, characteristics of PM_2.5 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 PM_2.5 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.