TY - JOUR
T1 - Influence of ozone and humidity on the formation of sulfate and nitrate in airborne fine particles
AU - Chang, Li P.
AU - Yao, Yung C.
AU - Liao, Che F.
AU - Chiang, Sheng W.
AU - Tsai, Jiun H.
N1 - Funding Information:
The authors gratefully acknowledge the National Science Council and the Environmental Protection Administration, Taiwan, Republic of China for supporting the study (NSC-93-2621-Z-006-004, NSC.94-2211-E-006-087 and NSC.95-2221-E-006-287). We would like to thank Professor Lin, J. J. and Chen, C.Y. for their assistance in sample analysis.
PY - 2009/1
Y1 - 2009/1
N2 - Ambient concentrations of HNO3 and SO2, and particulate NO3- and SO42 - were simultaneously measured in daytime and nighttime in southern Taiwan, to investigate the conversion effect of these inorganic species into airborne particulate. During the episode days, the average particulate nitrate mass of accumulation mode (0.18-1.8 m) measured over daytime and nighttime were about 3.9 and 7.6 times higher than those measured during non-episode days, respectively. The mean value of gaseous nitric acid was always higher during episode daytime than that during non-episode daytime. In addition, the SO42 - mass of accumulation mode during episode days was about 2.6 and 2.0 times higher than those during the daytime and nighttime of the non-episode days, respectively. Both of (1) the extent of SO2 oxidation to sulfate and NO2 oxidation to nitrate and (2) conversion ratios for sulfur (Fs) and nitrogen (Fn) were defined and calculated using field measurements. The nighttime Fn and Fs during the episode days were about 4 and 1.6 times higher, respectively, than those during the non-episode days. Furthermore, the Fs and Fn increased with the increase of relative humidity during both of the episode daytime and nighttime. A positive correlation coefficient that the Fn and Fs increases with increasing ozone concentration was found during the non-episode daytime. These results might be attributed to high NO2, SO2 and ozone concentrations in a humid atmosphere, and also the fact that the gas-to-particle conversion plays an important role during episode days.
AB - Ambient concentrations of HNO3 and SO2, and particulate NO3- and SO42 - were simultaneously measured in daytime and nighttime in southern Taiwan, to investigate the conversion effect of these inorganic species into airborne particulate. During the episode days, the average particulate nitrate mass of accumulation mode (0.18-1.8 m) measured over daytime and nighttime were about 3.9 and 7.6 times higher than those measured during non-episode days, respectively. The mean value of gaseous nitric acid was always higher during episode daytime than that during non-episode daytime. In addition, the SO42 - mass of accumulation mode during episode days was about 2.6 and 2.0 times higher than those during the daytime and nighttime of the non-episode days, respectively. Both of (1) the extent of SO2 oxidation to sulfate and NO2 oxidation to nitrate and (2) conversion ratios for sulfur (Fs) and nitrogen (Fn) were defined and calculated using field measurements. The nighttime Fn and Fs during the episode days were about 4 and 1.6 times higher, respectively, than those during the non-episode days. Furthermore, the Fs and Fn increased with the increase of relative humidity during both of the episode daytime and nighttime. A positive correlation coefficient that the Fn and Fs increases with increasing ozone concentration was found during the non-episode daytime. These results might be attributed to high NO2, SO2 and ozone concentrations in a humid atmosphere, and also the fact that the gas-to-particle conversion plays an important role during episode days.
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U2 - 10.1080/10934520902928370
DO - 10.1080/10934520902928370
M3 - Article
C2 - 19731834
AN - SCOPUS:70349582317
SN - 1093-4529
VL - 44
SP - 767
EP - 777
JO - Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
JF - Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
IS - 8
ER -