Sulfate aerosol and its acidity near Mae Moh Power Plant Lampang province

Abstract

A study of sulfate aerosol was conducted at Ban Tha Si and Ban Sob Pat located in the vicinity of Mae Moh Power Plant, Lampang Province during January 8-23, 1996. The measurements were taken twice per day (09.00 – 17.00 and 17.00 – 09.00). Fine (DP50 < 2.5 µm) aerosols were collected using Annular Denuder System and were analyzed for SO42- , H+ and NH3. SO42- were found average about 284.35 and 589.67 neq/m3 for daytime and nighttime, respectively. H+ concentrations were higher when SO42- concentrations increase. An average daytime SO2 value was higher than those in nighttime period. Aerosol acidity was evaluated in terms of the H+/SO42- equivalent ratio. 92.7% of acid aerosol were found in the partially neutralized acid phase (NH4) 3H (SO4)2 according to the high level of ammonia gas. The occurring damge could be caused by its deposition into the environment. The SO42 formation reaction was expected to be nonphotochemical processes with metal catalysts. The heavy metals (Fe and Mn) from the airborne particulate in the site areas were feasible. The high concentration of SO42- were detected which also indicated the high potential of SO2 transformation in the vicinity of Mae Moh Power Plant.