Fourteen nitro-PAHs and five oxy-PAHs associated with PM2.5 and PM1.0 were analyzed by GC-MS/MS at Mount Tai, China. 85% of the nitro-PAHs and 65% of oxy-PAHs were found in PM1.0. The combined concentration of nitro-PAHs in PM2.5 was highest in air masses associated with biomass burning (270.50pg/m3) compared with measurements from heavily polluted days (93.21pg/m3) and clean days (81.22pg/m3). A similar trend was also reflected in measurements of PM1.0. 9-FO, 9,10-ANQ, and 1-NALD were the most abundant oxy-PAHs in both PM2.5 and PM1.0 at Mount Tai. The concentration of 2+3N-FLA was markedly increased compared with other species on heavily polluted days and biomass burning days, and 9N-ANT was more concentrated in measurements from days with biomass burning emissions. Secondary generation of nitro-PAHs was also more active during periods with biomass burning. The main formation pathway of nitro-PAHs during the sampling campaign was through reactions with OH radicals, but NO3 radicals also played a significant role at night. The incremental lifetime cancer risk (ILCR) was highest during periods with biomass burning, indicating that biomass burning has a significant impact on human health. By analyzing the results of back trajectory clustering under different meteorological conditions, we determined that a large area of straw burning in the North China Plain (NCP) was the dominant source of nitro and oxy-PAHs at Mount Tai during the measurement campaign.
Keywords: Air masses transport; Biomass burning; Nitro-PAHs; Oxy-PAHs; PM(2.5) and PM(1.0).
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