Diurnal variation of chemical characteristics of PM10, PM2.5, PM1.0 and gaseous pollutants in the urban of Taiwan in Autumn

Abstract

The characteristics of particulate matter and gaseous pollutants differ depending on the human activities and natural emissions that occurred during that time. In this study, we characterized the chemical species of PM1 0 , PM2 . 5 , PM1 . 0 , and gaseous pollutants, and explore the relationships between chemical species of PM and gaseous pollutants during daytime and nighttime. The samples were collected in the urban of Tainan City, Taiwan, in the daytime and nighttime during Mid-Autumn Festival in autimn. The chemical characteristics of PM including organic matter and gaseous pollutants were investigated. The concentrations of HCl and SO2 were higher in the daytime due to industrial activities in the daytime. Meanwhile, HNO2 was higher in the nighttime compared with HNO3 was higher in the daytime due to the photochemical reaction that HNO2 transformed to HNO3 in the daytime. On the other hand, the average NH3 concentration in the daytime was 1 9 . 9 % lower than that of night NH3 due to atmospheric chemistry. All particle sizes were high concentration during MAF and higher in the daytime due to more human activities than in the nighttime. Oxalate, SO4 2-, and levoglucosan were dominant in organic matters in all particle sizes and high concentration during MAF. The night/day ratio in all particle sizes of oxalate and SO4 2- ranges to, 0.932-0.960 and 0.945-0.971, respectively due to industrial activities, transportation, and photochemical reaction. The night/day ratio in all particle sizes of levoglucosan ranges to 0.920-0.979 indicating that more biomass burning in the daytime and no impact of barbecue and burning of wood in the nighttime during MAF.