Comparative study of PM10/PM2.5-bound PAHs in downtown Beijing, China: Concentrations, sources, and health risks

Exposure to the PM ₁₀/PM _2.5-bound polycyclic aromatic hydrocarbons (PAHs) is a severe problem in heavily polluted cities in China. Designing effective air pollution management policies requires knowledge of the sources and health risks of PM ₁₀/PM _2.5-bound PAHs. This study investigates the comparative differences of meteorological influences on PM ₁₀/PM _2.5-bound PAHs distributions, as well as their potential sources and health risks. The aim of this study is to provide a science-based rationale for particle-bound PAHs pollution control. Both PM ₁₀ and PM _2.5 samples were collected in the center of Beijing, China in winter and summer from 2013 to 2015. The meteorological conditions were monitored simultaneously. An analysis of the correlation between meteorological variables and PAHs concentrations indicates that average temperature, rainfall, and solar radiation had the most significant influences on the PAHs concentrations. A Principal component analysis combined with a diagnostic ratio tool is applied to the source apportionment of particle-bound PAHs, which indicates that diesel, gasoline, and coal combustion contribute most to PAHs pollution. The high emissions of the PM ₁₀/PM _2.5-bound PAHs result in a 3.72 × 10 ⁻³/3.31 × 10 ⁻³ and 5.79 × 10 ⁻⁵/4.39 × 10 ⁻⁵ excess lung cancer risk in winter and summer, respectively. PM _2.5 contains more PAHs than the coarser fraction (PM _2.5-10), and accounts for 89% (winter) and 76% (summer) of the health risk caused by PM ₁₀. Given the higher risks caused by PM _2.5 than the PM _2.5-10 portion, PM _2.5 should be treated as the prioritized-control pollutant. Moreover, actively reducing the combustion of fossil fuels and a strategy of changing residents’ exposure characteristics are proposed for the mitigation of particle-bound PAHs pollution and control of health risks.