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Concentrations and Formation Rates of Ambient Nitrous Acid in Taichung City, Taiwan.
- Source :
- Environmental Engineering Science; Oct2008, Vol. 25 Issue 8, p1149-1158, 10p, 6 Charts, 3 Graphs, 1 Map
- Publication Year :
- 2008
-
Abstract
- This paper investigates the concentrations and formation rates of ambient nitrous acid (HNO<subscript>2</subscript>) in the urban atmosphere. Simultaneous measurements of HNO<subscript>2</subscript> and aerosol particles were carried out from July 2005 to January 2006 by using an annular denuder system (ADS). In addition, the formation rates of NO<subscript>x</subscript> to HNO<subscript>2</subscript> were assessed by evaluating potential reactions. The HNO<subscript>2</subscript> concentrations ranged from 0.1 to 15.3 μg m<superscript>−3</superscript> with a mean value of 2.9 μg m<superscript>−3</superscript>. The lower levels of HNO<subscript>2</subscript> found in the 10–14 and 14–18-h sampling intervals were due to photolytic reactions. Moreover, heterogeneous reactions of NO<subscript>2</subscript> and H<subscript>2</subscript>O on the aerosol surface contributed to the numerous production pathways of HNO<subscript>2</subscript> during nighttime, which was verified by experimental observations and theoretical evaluations. The formation rates of HNO<subscript>2</subscript> ranged from 0.5–2.6 % h<superscript>−1</superscript>, while the highest values were found at nighttime. Finally, the factors affecting the formation rate were investigated using sensitivity analysis. The results showed that HNO<subscript>2</subscript> was significantly dependent on NO concentration during daytime, whereas NO<subscript>2</subscript> was the major factor influencing the formation of HNO<subscript>2</subscript> during nighttime. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10928758
- Volume :
- 25
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Environmental Engineering Science
- Publication Type :
- Academic Journal
- Accession number :
- 34651965
- Full Text :
- https://doi.org/10.1089/ees.2007.0124