Monitoring of particulate hazardous air pollutants and affecting factors in the largest industrial area in South Korea: The Sihwa-Banwol complex

Ambient air monitoring of particulate hazardous air pollutants was performed from 2005 to 2007 in the Sihwa-Banwol industrial complexes, which is the largest industrial area in Korea. The occurrence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals, their spatial and seasonal distributions, and the factors affecting the variations in concentrations were investigated. The annual average concentration of benzo[a]pyrene was 1.27 ng/m3, with a maximum of 10.41 ng/m3. The PAH levels between the industrial and residential sites did not differ significantly, although heavy metals strongly related to industrial activities showed a clear variation between the two groups. Thus, industrial activities were not the only sources of PAHs; they also included automobile emissions and residential heating fuels. Coal-fired power plants outside the city and transboundary contributions from China and North Korea also affected the PAH levels in the area. Although ambient levels of heavy metals had no specific seasonal pattern, PAH levels showed distinct seasonal variations, with the highest level in winter. Factors affecting the PAH concentrations were vehicle exhaust, domestic heating, industrial activities, incineration within the area, and fuel combustion outside the area. The Sihwa-Banwol industrial complexes can be regarded as a hot-spot of PAH pollution in the Seoul metropolitan area.