Analysis of impacts on urban air quality by restricting the operation of passenger vehicles during Asian Game events in Busan, Korea

This study is an analysis of the impacts on urban air quality of restricting the operation of passenger vehicles during the 24th Asian Games (AG). Passenger vehicles in Busan were not allowed to operate on the alternative days during the AG period. This restricted operation of passenger vehicles was enforced to improve an urban air quality in Busan during the AG period. The average usage rate of passenger vehicles under an alternate (or restricted) operation was 95.4% and thus the average traffic flow rate (vehicle operation speed) increased approximately 28.1% as compared to normal periods. We analyzed the ambient concentrations of criteria air pollutants measured at 13 air-monitoring stations in Busan (Pusan), Korea, for the three periods of “before (13–28 September 2002)”, “during (29 September–14 October 2002)” and “after (15–30 October 2002)” the AG. The 1-h, 24-h and 16-day averages or median concentrations of each classified term were compared to those of other terms. The median concentrations, based on 24-h average data of each day, of PM10, CO, NO2, and SO2 in the ambient during the alternate operation period of 16 days substantially increased as compared to the terms before or after. However, the median concentration of O3 during the AG period was slightly less than that of the term before. The ambient O3 concentrations during daytime (12:00–19:00) under alternate operation substantially increased as compared to the terms before or after. However, the ambient O3 concentrations during nighttime (22:00–07:00) under alternate operation decreased when compared to the terms before or after. For the alternate operation period of passenger vehicles, the average concentrations of PM10, NO2, SO2, and daytime O3 measured at the air-monitoring stations near the stadiums were much higher than those of the other areas excluding the stadium areas. However, average CO concentrations at the other areas were higher than those nearby the stadiums during the alternate operation period.