摘要
The mass concentration and major chemical components of fine particulate matter were measured before,during and after Beijing＇s massive parade commemorating 70th anniversary of the Chinese Victory in World War II on September 3,2015.Regional emission inventory,positive matrix factorization（PMF）,observations from space and backward air mass trajectories were jointly applied to identify the major pollution sources and their temporal and spatial variations.The contributions of emissions variations and the meteorological conditions related to the＂parade blue＂phenomenon in Beijing and its surrounding areas were investigated in detail.The main cause of the decreased PM（2.5）mass concentration was attributed to the absolute reduction in emissions of primary air pollutants.The chemical composition of PM（2.5）varied significantly before,during and after the parade.Fugitive dust particles were well controlled,the secondary formation of PM（2.5）was reduced along with the controlled gaseous precursors＇emissions from vehicles and industrial sources during the temporary intensified control period.During the parade period,the SO2and NO2column concentrations in Beijing and the surrounding areas decreased sharply,indicating that the coordinated reduction in primary emissions from the surrounding areas of Beijing played an important role in lowering the ambient concentration of SO2and NO2and accordingly lowered PM（2.5）and improved the regional air quality.A comparison of the temperature,humidity,and wind speed and direction during the same periods in 2014 and 2015 showed that the meteorological conditions positively influenced the achievement of＂parade blue＂.
The mass concentration and major chemical components of fine particulate matter were measured before,during and after Beijing＇s massive parade commemorating 70th anniversary of the Chinese Victory in World War II on September 3,2015.Regional emission inventory,positive matrix factorization（PMF）,observations from space and backward air mass trajectories were jointly applied to identify the major pollution sources and their temporal and spatial variations.The contributions of emissions variations and the meteorological conditions related to the＂parade blue＂phenomenon in Beijing and its surrounding areas were investigated in detail.The main cause of the decreased PM（2.5）mass concentration was attributed to the absolute reduction in emissions of primary air pollutants.The chemical composition of PM（2.5）varied significantly before,during and after the parade.Fugitive dust particles were well controlled,the secondary formation of PM（2.5）was reduced along with the controlled gaseous precursors＇emissions from vehicles and industrial sources during the temporary intensified control period.During the parade period,the SO2and NO2column concentrations in Beijing and the surrounding areas decreased sharply,indicating that the coordinated reduction in primary emissions from the surrounding areas of Beijing played an important role in lowering the ambient concentration of SO2and NO2and accordingly lowered PM（2.5）and improved the regional air quality.A comparison of the temperature,humidity,and wind speed and direction during the same periods in 2014 and 2015 showed that the meteorological conditions positively influenced the achievement of＂parade blue＂.
基金
funded by the National Natural Science Foundation of China (Nos. 21377012, 21177012, 40975061)
the National Science and Technology Support Programme of the Ministry of Science and Technology of China (Nos.2014BAC23B02, 2014BAC06B05)
the Special Programme on Public Welfare of the Ministry of Environmental Protection (No. 201409022)
