Characteristics Of Water-soluble Ionic Species In Fine (pm2.5) And Coarse Participate Matter (pm_(10-2.5)) In Kaohsiung, Southern Taiwan

摘要

Eleven ionic species and fine and coarse particle mass concentrations of fine (PM_(2.5)) and coarse (PM_(10-2.5)) par-ticulate matter were investigated in Kaohsiung,southern Taiwan.The PM_(2.5) and PM_(10-2.5) particulate concentrations were 49-64 and 34-37 μg·m~(-3),respectively.Fifty-five to 64% of the particulate matter less than 10 μm in aerodynamic diameter (PM_(10)) mass was attributed to the PM_(2.5).PM_(2.5) concentrations at Daliao (a rural and industrial complex area) were higher than at Tzuoying (an urban and industrial complex area).Ionic species contributed 45-53% and 42-45% of PM2.5 and PM10,respectively.Potassium ions (K~+),sulfate (SO_4~(2-)),and ammonium (NH_4~+) were predominant in PM_(2.5),whereas sodium,calcium,and magnesium ions were foremost in PM_(10-2.5).Nitrate (NO_3~-) existed in both the PM_(2.5) and PM_(10-2.5). Chloride (Cl~-),NO_3~-,and NH_4~+ concentrations were higher at night than during the day,and they were easily transferred into the gas phase by photochemical reactions and temperature-induced volatilization.The NH_4~+/SO_4~(2-) ratios were 2.6 and 2.5 at Daliao and Tzuoying,respectively,which indicated that both sampling sites were rich in NH_4~+.Therefore,ammonium nitrate would be present in the area.