Atmospheric Occurrence and Concentrations of PAHs and Heavy Metals in Pohang

Abstract

This study was carried out to investigate seasonal and spatial variations of particulate hazardous air pollutants (HAPs), such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, by sampling total suspended particles (TSP) in the atmosphere of a steel industrial city. TSP samples were collected using high-volume air samplers at two sites (residential and industrial areas) in Pohang and one control site in Gyeongsan in four seasons from February to October 2012. The PAHs and heavy metals were determined by GC-MS and ICP-AES, respectively. The average concentrations of PAHs in the industrial area were about twice that in the residential area, while the PAH levels of the residential area in Pohang were similar to those in Gyeongsan. Seasonal variation in the PAH concentrations was distinct, with the highest observed in winter and the lowest in summer. The average concentration of BaP in winter was 0.80 ng/m3, which is about 4 times of the summer average (0.19 ng/m3). However, the mass ratio of PAH concentration (ng/m3) divided by TSP concentration (μg/m3) revealed different spatial and seasonal variations from those of the mass to air concentrations (ng/m3). This implies that although TSP and PAH concentrations varied seasonally and spatially, the content of PAHs in the airborne dust in Pohang area may not change significantly. The impact of industrial activities on the atmospheric heavy metals also appeared to be significant, as the concentrations of most heavy metals in the industrial site were substantially higher than the residential and control sites. Therefore, in order to reduce the concentrations of particulate HAPs, including PAHs and heavy metals, in Pohang City, where several steel industrial complexes are located, it is necessary to intensively control the emission sources in the industrial complexes and heavy-duty diesel vehicle emissions