Major factors affecting the ambient particulate nitrate level at Gosan, Korea

Major factors that determine the ambient particulate nitrate concentration at Gosan, Jeju Island, Korea are identified based on the inorganic ionic and elemental data in TSP and PM2.5 measured between March 1998 and February 2003. It was found that the nitrate in TSP was highly correlated with crustal species such as nss-Ca2+ and nss-Mg2+, while nitrate in PM2.5 was highly correlated with anthropogenic species such as NH4+. In the high nitrate cases in TSP, the concentrations of crustal species and NH4+ were high and the air parcels moved mostly from Mongolia. In the high nitrate cases in PM2.5, the concentration of NH4+ was high and the air parcels moves mostly from southern China. It was found that the air parcels were mainly from the Pacific Ocean for the low nitrate cases. Still there was significant number of the low nitrate cases with air parcels from Mongolia for both TSP and PM2.5. In these cases, the concentrations of crustal species were low for TSP and those of NH4+ were low for PM2.5. Therefore, the most important factors that determined the level of nitrate were the concentration of crustal species for TSP and the concentration of NH4+ for PM2.5 irrespective of air parcel movement.