Condensable and filterable particulate matter emission of coal fired boilers and characteristics of PM_2.5-bound polycyclic aromatic hydrocarbons in the vicinity

In this research, we simultaneously studied the characteristics of particulate matter-bound PAHs from two industrial coal fire boilers, one highway tunnel, and PAHs from the ambient air of each source. In the stack gas, condensable particulate matter (CPM) was 10–30 times higher than filterable particulate matter (FPM_2.5). The content of PAHs in each mg of PM_2.5 at emission stack (479 ± 284 ng BaPeq/mg) was reduced by 1.7 times at the industrial vicinity (282 ± 264 ng BaPeq/mg). Inside the tunnel, the PAH content was (138 ± 23.8 ng BaPeq/mg). Such value was reduced with the reduction of human activities from urban (40.8 ± 22.3 ng BaPeq/mg) to rural (34.4 ± 23.9 ng BaPeq/mg) and background areas (3.03 ± 1.94 ng BaPeq/mg). Indeno[1,2,3-cd]pyrene and Benzo[g,h,i]perylene were found to be the major contributor of PAHs from the industrial emission (25–30%) and traffic source (60%). Source apportionment in ambient PAHs found fossil fuel burning (for both industry and traffic purposes), incineration, and biomass burning was major contributors of PAHs in the ambient air in Taiwan. Excessive cancer risk in the vicinity of industrial areas and central regions of Taiwan was higher than the EPA standard threshold of 10⁻⁴.