Site-specific variation in mass concentration and chemical 2 components in ambient nanoparticles (PM0.1) in North 3 Sumatra Province-Indonesia

In this study, as the first step in mitigating contamination by PM0.1, particles with diameters less than 0.1 μm, the current air pollution situation in Indonesia was investigated with respect to particulate matter (PM), especially regarding the status and characteristics of PM0.1. Air sampling in different size ranges down to PM0.1 was conducted at roadsides, at a school adjacent to a road, an industrial area and an area near a volcano in North Sumatera Province. Analyses were conducted for carbonous components (OC, EC, TC, WSOC and WISOC), and ions including oxalate in the PM0.1 fraction. We identified PM2.5 and PM10 mass concentrations in the area of the city that exceeded WHO guidelines. From the chemical components in the PM0.1 fraction, we found that WISOC, NO3− and soot-EC were the most common components, suggesting that local traffic is a contributor and another group consisting of K+, SO42− and WSOC suggesting the occurrence of biomass burning related to local industrial and rural sources.