Effect of precipitation on air pollutant concentration in Seoul, Korea

The washout removal efficiencies of precipitation on PM₁₀ and NO₂ concentration in Seoul, Korea, were quantitatively estimated. Precipitation data of Seoul monitored by the Korean Meteorological Administration from 1999 to 2008 were used. The correlation between average concentration decrease and amount of rainfall was quite high for PM₁₀, but, naturally, there was an inherent numerical error because of using averages. By contrast, NO₂ had no obvious correlation at both the urban air monitoring site and the road side monitoring site. The estimated annual reduction effect by precipitation at the Seosomun urban air monitoring site for PM₁₀ was 0.88 μg/cu m. Average reduction effects for NO₂ at urban and roadside air monitoring sites were 0.20 and 0.22 ppb, respectively. The reduction effect by precipitation at the urban site in 2008 was highest (0.44 ppb) and 2005 showed an effect as little as 0.01 ppb. This is an abstract of a paper presented at the 103rd Air and Waste Management Association Annual Conference and Exhibition (Calgary, Alberta, Canada 6/22-25/2010).