Source analysis and health risk assessment of polycyclic aromatic hydrocarbons in atmospheric PM2.5 in a district of Taizhou City from 2019 to 2021

Background Polycyclic aromatic hydrocarbons (PAHs), one of the main components of fine particulate matter (PM2.5), have a certain impact on ambient air quality, and long-term exposure to PAHs may pose potential health risks to human beings. Objective To identify the distribution characteristics and sources of PAHs in atmospheric PM2.5 in a district of Taizhou City from 2019 to 2021, and to evaluate the health risks of PAHs to the population in the area through the inhalation pathway. Methods From 2019 to 2021, air PM2.5 sampling was carried out at a state-controlled surveillance point in a district of Taizhou City for 7 consecutive days on the 10th-16th of each month, the sampling time was 24 h·d−1, and the sampling flow rate was 100 L·min−1. PM2.5 mass concentration was calculated by gravimetric method. A total of 16 PAHs were determined by ultrasonic extraction-liquid chromatography. Kruskal-Wallis H test was used to compare the distribution charac teristics of PAHs concentrations by years and seasons, characteristic ratio and principal component analysis (PCA) was used to analyze their sources, and a lifetime carcinogenic risk (ILCR) model was used to assess the health risk of PAHs. Results From 2019 to 2021, the annual average concentrations [M (P25, P75)] of ∑PAHs in atmospheric PM2.5 in the selected district of Taizhou City were 6.52 (2.46, 10.59), 8.52 (4.56, 12.29), and 3.72 (1.51, 7.11) ng·m−3, respectively, and the annual benzo[a]pyrene (BaP) excess rates (national limit: 1 ng·m−3) were 27.38% (23/84), 47.62% (40/84), and 19.04% (16/84), respectively, both presenting 2020> 2019 > 2021 (P