杭州市灰霾与非灰霾日不同粒径大气颗粒物来源解析

在2011年典型灰霾和非灰霾天气下,采集了杭州市不同粒径的大气颗粒物样品,测定并分析各粒径段颗粒物的质量浓度及其化学成分；同时采集并分析了主要污染源排放的颗粒物样品,通过CMB(化学质量平衡)模型进行源解析. 结果表明:灰霾天气下,二次粒子是杭州市各粒径段颗粒物的首要贡献源,其对≤1.1、>1.1~3.3、>3.3~5.8和>5.8~10μm粒径段的颗粒物贡献率分别为60.4%、62.2%、54.8%和46.5%. 在一次排放源中,机动车尾气是≤1.1和>1.1~3.3μm粒径段颗粒物的重要来源,贡献率分别为13.8%和12.2%；城市扬尘是>3.3~5.8μm粒径段颗粒物的重要来源,贡献率达到16.0%;而建筑施工尘是>5.8~10μm粒径段颗粒物的重要来源,贡献率为14.2%. 非灰霾天气下,随着颗粒物粒径的增加,二次粒子的贡献率显著下降,对≤1.1μm粒径段颗粒物的贡献率为42.7%,而对>5.8~10μm粒径段颗粒物的贡献率仅为15.5%；机动车是各粒径段颗粒物的重要贡献源,贡献率均在20%以上；煤烟尘是≤3.3μm细粒径段颗粒物的重要贡献源类,贡献率为22.0%；城市扬尘是>3.3~5.8μm粒径段颗粒物的重要来源,贡献率为18.3%；建筑施工尘依然是>5.8~10μm粒径段颗粒物的重要来源,贡献率为21.4%. 

Source Apportionment of Particulate Matters in Different Size Bins during Hazy and Non-Hazy Episodes in Hangzhou City

During hazy and non-hazy episodes in 2011, the size-segregated particulate matters were sampled in four sites using Anderson particulate cascade impactor in Hangzhou City urban area. The mass concentrations of PM in different size bins and their chemical species had been analyzed. The receptor and source profiles had been constructed, and the size-segregated source apportionment of PM had been done by using the chemical mass balance (CMB) receptor model. Modeled results revealed that there was a significant difference of source contributions between hazy and non-hazy days. In hazy days, the main source of PM mass concentrations were secondary particles, contributing by 60.4%, 62.2%, 54.8% and 46.5% respectively to PM in different size bins (≤1.1, >1.1-3.3, >3.3-5.8and >5.8-10μm). Among the main pollution sources, vehicle emission was an important contribution source to the fine PM less than 1.1μm and between >1.1-3.3μm, contributing 13.8% and 12.2% respectively. Re-suspended dust and cement dust were important sources to PM in >3.3-5.8and >5.8-10μm size bins respectively, contributing 16.0% and 14.2%, respectively. In non-hazy days, with the increase of the particulate size, the contribution of secondary particles decreased sharply, contributing to the fine PM (≤1.1μm) of 42.7% and to coarse PM (>5.8-10μm) of only 15.5%. Vehicle emission was the major source, contributing over 20% to the measured PM mass in each size bin. Coal combustion dust was also an important source to fine PM (≤3.3μm) with 22.0% contribution rate, while re-suspended dust was the important source to intermediate size particles (>3.3-5.8μm) and cement dust was the important source to coarse PM in >5.8-10μm size bin.