Isotopic signatures and source apportionment of Pb in ambient PM2.5

Particulate lead (Pb) is a primary air pollutant that affects society because of its health impacts. This study investigates the source sectors of Pb associated with ambient fine particulate matter (PM2.5) over central-western Taiwan (CWT) with new constraints on the Pb-isotopic composition. We demonstrate that the contribution of coal-fired facilities is overwhelming, which is estimated to reach 35 +/- 16% in the summertime and is enhanced to 57 +/- 24% during the winter monsoon seasons. Moreover, fossil-fuel vehicles remain a major source of atmospheric Pb, which accounts for 12 +/- 5%, despite the current absence of a leaded gasoline supply. Significant seasonal and geographical variations in the Pb-isotopic composition are revealed, which suggest that the impact of East Asian (EA) pollution outflows is important in north CWT and drastically declines toward the south. We estimate the average contribution of EA outflows as accounting for 35 +/- 15% (3.6 +/- 1.5 ng/m(3)) of the atmospheric Pb loading in CWT during the winter monsoon seasons.

Automated summary

This study investigates the sources of particulate lead in central-western Taiwan and finds that coal-fired facilities are the main contributor, accounting for about 35% in summer and increasing to 57% during the winter monsoon seasons. Despite the absence of leaded gasoline supply, fossil-fuel vehicles remain a significant source, accounting for about 12%. The study also reveals seasonal and geographical variations in the lead isotopic composition, indicating the importance of East Asian pollution outflows in the northern part of Taiwan.