Characteristics, sources, and health risks of ambient nanoparticles (PM<inf>0.1</inf>) bound metal in Bangkok, Thailand

Abstract

The objective of this study was to characterize ambient nanoparticles (PM0.1)-bound metals in Bangkok, Thailand and assess the health risks of these materials to human. A year-long sampling campaign was conducted between November 2014 and October 2015. The PM0.1 mass concentration ranged from 10 to 27 μg/m3, and the average PM0.1 mass concentration was 15 ± 2 μg/m3. The total concentration of the thirteen elements was 345 ± 31 ng/m3, with Fe, K, Na, Al, Cu, Mg, and Zn (>10 ng/m3) being the dominant species. The highest total element concentration occurred in the cold dry season followed by the hot dry and wet seasons. A principal component analysis (PCA) indicated that the primary sources of PM0.1 were derived from road traffic, the industrial sector, and biomass burning. The high concentrations of metals found in the cold dry season suggest that PM0.1-bound metal derived from road traffic and biomass burning from neighboring areas were transported to Bangkok. High level of K indicates that biomass burning was a major source during cold dry season. Total cancer risk from all the carcinogenic elements was 5.84 × 10−6 in adults, which does not exceed the upper limit of the acceptable risk assessment range. The findings of this study provide further clarification of the emission source profile and the pattern of PM0.1 particles and should be of value for emission control and mitigation of PM emission in an urban area.