利用自行研制的大气细粒子谱分析仪、振荡天平、大气能见度仪和气象参数仪,对2008年北京奥运期间的主场馆区域大气质量状况进行了连续在线测量。奥运期间粒子日平均数浓度变化表明,核模态粒子(5-20 nm)主要受气相成核过程的影响,数浓度变化曲线呈单峰值结构;爱根核模态(20-100 nm)受人为源及核模态粒子贡献影响较大,数浓度曲线呈典型的三峰值结构;积聚模态(100 nm-1 μm)数浓度日变化不大,但受降水等天气因素影响较大。结合地面能见度数据,对降雨、灰霾和晴好天气状态下大气细粒子谱变化特征进行分析,结果表明,降雨对颗粒物的清除作用与颗粒物粒径大小密切相关,而灰霾天气下大气能见度的降低主要受积聚模态粒子散射消光的影响。同时,利用细粒子数浓度计算得到粒径小于10 μm的颗粒(PM10)质量浓度,计算值与振荡天平实测值具有较好的一致性,相关系数达86.1%。

The atmospheric qualities of Olympic national stadium were measured by using the fine particulate meter (FPM),tapered element oscillating microbalance (TEOM,with a PM10 cutting head),visibility sensor and meteorological analyzer during Beijing 2008 Olympic games from 8 to 24 August,2008. The variation trend of diurnal average of particle number concentration showed that the nucleation mode (5-20 nm) was closely related to the nucleation process,and the concentration curve was unimodal. Atiken mode (20-100 nm),with curve of three peak values,was stronger influenced by human activities and growing process of nucleation mode. Accumulation mode,with a tiny trend for its diurnal average particle number concentration,was strongly affected by the weather conditions such as rain. The visibility,the particle number size distribution in rainy,haze and sunny weather conditions were also summarized. The conclusion that scavenging action of rain to the particles had close relation with particle size,and lower visibility in haze day was caused by the scattering excitation of accumulated mode particulate. Mass concentration of PM10 was calculated using the data of particle number concentration,and it showed a good coincidence with PM10 directly measured by TEOM. The correlation coefficient could achieve 86.1%.