Effect of Precipitation on Air Pollutant Concentration in Seoul, Korea

• Published in: Asian journal of atmospheric environment (Online) Vol. 8; no. 4; pp. 202 - 211
• Main Authors: Kim, Suhyang, Hong, Ki-Ho, Jun, Hwandon, Park, Young-Jae, Park, Moojong, Sunwoo, Young
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.12.2014; Springer; 한국대기환경학회
• Subjects: air pollution; inter-event time definition; no2; pm10; precipitation; 대기과학; NO; Air pollution; Precipitation; PM; Inter-event time definition
• ISSN: 2287-1160; 1976-6912; 2287-1160
• DOI: 10.5572/ajae.2014.8.4.202

In this study, long-term rainfall data with irregular spatial distribution in Seoul, Korea, were separated into individual precipitation events by the inter-event time definition of 6 hours. Precipitation washout of PM 10 and NO 2 concentrations in the air considering various complex factors were analyzed quantitatively. Concentrations of PM 10 and NO 2 in the atmosphere were lower under condition of rainfall compared to that of non-precipitation, and a noticeable difference in average PM 10 concentrations was observed. The reduction of concentrations of PM 10 and NO 2 by rainfall monitored at road-side air monitoring sites was also lower than that of urban air monitoring sites due to continuous pollutant emissions by transportation sources. Meanwhile, a relatively smaller reduction of average PM 10 concentration in the atmosphere was observed under conditions of light rainfall below 1 mm, presumably because the impact of pollutant emission was higher than that of precipitation scavenging effect, whereas an obvious reduction of pollutants was shown under conditions of rainfall greater than 1 mm. A log-shaped regression equation was most suitable for the expression of pollutant reduction by precipitation amount. In urban areas, a lower correlation between precipitation and reduction of NO 2 concentration was also observed due to the mobile emission effect.