南通市区大气气溶胶物理特性分析

Physical Characteristics of Atmospheric Aerosol in the Downtown Area of Nantong

使用GRIMM180对2017年12月—2018年11月南通市区四季0.25~32μm粒径段大气气溶胶数浓度进行连续观测,对其变化特征进行了分析。春、夏、秋、冬四季数浓度分别为396个/cm^(3)、281个/cm^(3)、265个/cm^(3)、519个/cm^(3)。春季PM_(1-32)的气溶胶日变化呈单峰分布,峰值位于11∶00;夏季PM 0.25-1及PM 2.5-32的气溶胶日变化呈单峰分布,峰值位于12∶00,与太阳辐射有关;秋季PM_(0.25-32)和冬季PM_(0.25-2.5)的气溶胶日变化呈双峰分布,峰值位于8∶00—10∶00和18∶00—19∶00,受早晚高峰影响。气溶胶四季数浓度谱峰值均为0.29μm,数浓度主要由1μm以下的细粒子贡献,粗粒子贡献很少,>1μm的粒子数浓度维持在较低水平。随着小颗粒物数浓度的增加,空气质量状况的下降更为突出,尤其是0.5~1μm的颗粒物。

In this study,GRIMM180 was used to continuously observe the atmospheric aerosol number concentration in the section 0.25~32 micron particle size in the downtown area of Nantong city and analyze its variation characteristics from December of 2017 to November of 2018.The number concentrations of spring,summer,autumn and winter were 396/cm^(3),281/cm^(3),265/cm^(3) and 519/cm^(3),respectively.In spring,the daily changes of PM_(1-32)demonstrated a single peak distribution,and the peak occurred at 11∶00am.In summer,the daily changes of PM 0.25-1 and PM 2.5-32 showed a single peak distribution,and the peak was at the time of 12∶00am,which is closely related to solar radiation.The daily changes of PM_(0.25-32)both in autumn and winter demonstrated both peaks,the peak happened between 8∶00~10∶00am and 18∶00~19∶00pm,which were affected by morning and evening peaks.The peak values of the four seasons number-concentration spectrum of aerosols were 0.29 micron,and the number-concentration was mainly contributed by fine particles under 1 micron,while the contribution of coarse particles was very little.The concentrations of particles greater than 1 micron remained relatively low.As the concentration of small particles increased,the decline of air quality became more prominent,especially those between 0.5 and 1 micron.