Journal of the Korean Geographical Society ISSN:1225-6633(Print) 대한지리학회지

Frequent occurrences of high PM10(particulate matter ≤10μm) concentrations have become a serious environmental concern in Korea due to their direct threat to public health, but the impacts of rainfall factors on PM10 concentrations are not well known. This study analyzed 15-year long PM10 data over Busan Metropolitan City(BMC) to quantify the washout effect of precipitation on PM10 concentrations in the city. Two different washout ratios, the aggregated washout ratio(AWR) and the immediate washout ratio(IWR), were suggested as a washout indicator. Seasonal mean washout ratios were highest in spring followed by summer, fall, and winter for both washout ratios. However, monthly analyses showed that rainfall variables, such as its amount, frequency, intensity, and the number of consecutive rainy days, did not have consistent correlations with the washout ratios. The cumulative impact of consecutive rainy days, typically ranging from 1 to 4 days, on the PM10 washout effect was also inconsistent. Study results indicated that the cumulative rainfall during a rainy period and the length of a rainy period had only a limited correlation with IWR on the monthly basis.