Abstract: A 3-D Eulerian regional air quality model, CAMx, is used to simulate the temporal variation and spatial distribution of PM10 in Beijing during summertime. The results show the prominent temporal and spatial variation characters of PM10. PM10 diurnal variation shows peaks around midnight and in the morning, an increasing trend around noon in urban areas because of the secondary aerosol production from photochemical reactions, a lowest concentration in early evening. The spatial distribution of PM10 has close relation to the source emission and is affected by the secondary aerosol production from photochemical reactions around noon. The secondary aerosol is an important portion of PM10. The secondary aerosol plays a main role on the concentration variation of sulfate and nitrate, while the concentration level and variation of organic carbon aerosol and PM10 is determined mainly by the primary aerosol.

Key words: PM10, numerical simulation, secondary aerosol

摘要： 利用三维区域空气质量模式CAMx，对北京地区夏季PM10浓度的时间变化规律和空间分布特征进行了数值模拟研究。结果表明，北京市城近郊区夏季的PM10具有明显的时空变化规律。一般在半夜前后和早晨常表现出较高的浓度；中午前后由于大气化学转化对二次气溶胶的生成贡献，在城市地区也会表现出一定的高浓度值；傍晚前后往往是一天中浓度最低的时段。PM10的空间分布与源排放关系密切，中午前后的空间分布会体现出光化学反应对其二次生成作用的影响。二次气溶胶在PM10中占有相当的份额，对于PM10中硫酸盐和硝酸盐的浓度变化，其中的二次组分起主要决定作用，而有机碳气溶胶以及PM10的浓度水平和变化规律则主要受一次成分的影响。

关键词: PM10, 数值模拟, 二次气溶胶