基于多源观测资料的海峡西岸城市春季颗粒物污染研究

以海西区沿海城市为研究对象,重点分析了厦门地区2017年春季大气颗粒物污染过程中边界层要素演变及颗粒物水平和垂直分布特征,并利用地面观测数据、气溶胶激光雷达、卫星遥感分析等多源观测资料,探讨了3月1—2日颗粒物污染过程.研究表明,海西区颗粒物污染过程中,暖区条件下静稳小风和高温高湿条件有利于局地细颗粒物的吸湿增长,细颗粒物占比较高,而在受冷锋南下影响下东北大风和高湿条件下,粗颗粒占比较高;海西区沿海各城市的细颗粒污染趋势基本一致,而粗颗粒污染峰值在沿海城市由北向南依次出现,表现出显著的向南传输的特征;海西区细颗粒污染主要集中在近地面层,受人为源排放累积影响,粗颗粒则是由外源输入,并沉降至近地面附近;冷空气南下过程中,在由锋前暖区的静稳条件向冷锋过境转变时,气溶胶污染由局地累积向区域传输转变,颗粒物尺度也从细颗粒物转变为粗颗粒物.海西区空气总体较为清洁,在污染相对较小条件下,颗粒物污染是通过多来源、多尺度的污染物造成的,是受细颗粒局地源产生和输送及外源粗颗粒物的输入和沉降共同影响的.

Study on spring particle matter pollution in coastal cities over West Bank of Taiwan Strait based on multi-source observations

In this study focusing on the particular matter (PM) pollution in spring 2017 over the West Bank of Taiwan Strait (WBTS), especially in Xiamen, we analyzed the horizontal and vertical distribution characterize of PM and other elements in boundary layer by using surface meteorological and environmental data, aerosol radar, aerosol models and satellite remote sensing data. The results indicated that fine particle showed relatively high proportion caused by weakly wind and relatively high temperature in warm period, which was advantaged for local hygroscopic growth, whereas the coarse pollution appeared under strong northern wind in period of cold front that moving southward during aerosol pollution in WBTS. The fine particle pollution showed same trend of variations over coastal cities in WBTS, but the coarse particle peak over cities of WBTS appeared in turns from north to south, indicated a long distance transport of PM over East China. Analyze vertical varying of extinction coefficient and depolarization by using aerosol radar data, the fine particle pollution was accumulated in lower boundary layer produced from local anthropogenic emission. External coarse particle was transported into WBTS from the Yangtze River Delta or the North China Plain before subsided to ground. In summary, the transformation processes from fine particle pollution to coarse particle pollution or from local accumulation to regional transport were due to the change of weather situation of the cold front and the warm period before cold front. As the WBTS''s air quality was well over East China, PM pollution formatted by multi-source and multi-scale pollutants in this area that were influenced by both local accumulation and regional transport.