Long-term Trends of the Concentrations of Mass and Chemical Composition in PM2.5 over Seoul

The literature data of the mass concentrations of TSP, PM10, and PM2.5, and chemical composition of PM2.5 (sulfate, nitrate, ammonium, OC, and EC) from 1985 and 2013 at Seoul were collected and the temporal trends were discussed in relation with the policy directions. Generally, the mass concentrations of TSP, PM10, and PM2.5 at Seoul have showed decreasing trends. However, it is not clear what might be the major reason(s) for the trends. The concentrations of ionic component in PM2.5 showed different trends, sulfate being reduced during the 1990s but no trend during the 2000s. The concentrations of nitrate and ammonium were increasing during the 2000s. The concentrations of OC show no apparent trend while that of EC decreased. Further policy directions are suggested based on the temporal trends of the chemical composition in PM2.5 .