Articles | Volume 18, issue 7
Research article
11 Apr 2018
Research article |  | 11 Apr 2018

Seasonal variation and chemical characterization of PM2.5 in northwestern Philippines

Gerry Bagtasa, Mylene G. Cayetano, and Chung-Shin Yuan

Abstract. The seasonal and chemical characteristics of fine particulate matter (PM2.5) were investigated in Burgos, Ilocos Norte, located at the northwestern edge of the Philippines. Each 24 h sample of fine aerosol was collected for four seasons. Fine particulate in the region shows strong seasonal variation in both concentration and composition. Highest mass concentration was seen during the boreal spring season with a mean mass concentration of 21.6 ± 6.6 µg m−3, and lowest was in fall with a mean concentration of 8.4 ± 2.3 µg m−3. Three-day wind back trajectory analysis of air mass reveals the influence of the northwestern Pacific monsoon regimes on PM2.5 concentration. During southwest monsoon, sea salt was the dominant component of fine aerosols carried by moist air from the South China Sea. During northeast monsoon, on the other hand, both wind and receptor model analysis showed that higher particulate concentration was due to the long-range transport (LRT) of anthropogenic emissions from northern East Asia. Overall, sea salt and soil comprise 33 % of total PM2.5 concentration, while local biomass burning makes up 33 %. LRT of industrial emission, solid waste burning and secondary sulfate from East Asia have a mean contribution of 34 % to the total fine particulate for the whole sampling period.

Short summary
Monsoon seasons are known to affect weather and climate in the Philippines. These shifting winds also cause the movement of pollutants in Asia. In this study, we found that during the northeast monsoon, pollution emissions from northern East Asia reach the northern part of the Philippines. On average, these transported pollutants make up a third of observed pollutants in the region.
Final-revised paper