The trend of the PM10 concentrations in the Seoul Metropolitan Area (SMA) is reviewed and
relative contributions of major contributors (paved road emissions and long-range transport
from outside the SMA) are discussed. It was shown that the PM10 concentrations in the SMA
have generally decreased except Incheon between 1999 and 2005. Further, it was identified that
the difference of the PM10 mass concentration between the roadside stations and urban
ambient stations has decreased between 2004 and 2008. Based on the emission estimates, it was
suggested that the reduction of resuspension of aerosols on the road is the major reason for that.
Based on the modeling results, it was identified that outside effects be about 30% of the ambient
PM10 concentration in the SMA. Further research and policy issues to identify major sources of
PM10 in the SMA are discussed.