关键词: NO_x, 北京, 减排, 空气质量, APEC

Abstract:

A comprehensive analysis of the variations of air quality and meteorological conditions was conducted for two major events(IAAF World Championships and September 3 Military Parade ceremony) in Beijing during the period from 20 August 2015 to 3 September 2015 when intense control measures were taken. Average concentrations of NO, NO₂, and PM_2.5 were 2.0, 22.7, and 17.8 μg·m³, respectively, during the two major events, and significantly decreased by 58.3%, 52.1%, and 73.2%, respectively, compared to those during the same period in 2014. The air quality in that period is called as "Parade Blue". After implementation of emission control measures, peak concentrations of NO were reduced by about 43% at traffic stations and by about 45% at urban environmental stations, and NO₂ concentrations for both early peak hours and nighttime accumulated slower than usual. Furthermore, the regional high NO₂ concentration center and a gradient PM_2.5 distribution pattern in Beijing both disappeared during the events. Due to the weak northern wind, the NO₂ concentration peak in early morning disappeared, which was different from the situation during the APEC meeting in 2014. However, the NO₂ peak in early morning was significantly higher than that at night during the two major events. Reductions in emissions and ambient pollutant concentrations during the two major events were both slightly larger than those during the APEC meeting.

Key words: NO_x, Beijing, pollution control measures, air quality, APEC