基于SPAMS的太原市典型生活区停暖前后PM2.5来源及组成

为分析太原市采暖期和非采暖期PM_2.5的特征，利用单颗粒气溶胶质谱仪（SPAMS）分析太原市典型生活区采暖期（2016年3月11-18日）和非采暖期（2016年4月1-7日）PM_2.5的来源及组成.结果表明:① 采暖期（停暖前）颗粒物有机碳、硫酸盐和多环芳烃等信号强度大于非采暖期（停暖后），而元素碳、硝酸盐、铵盐等反之.② 为了尽可能排除气象因素的影响，选取风向（东南风）、风级（二级）相同时段的颗粒物进行分析，停暖前后颗粒物主要化学组分为有机碳、混合碳和元素碳，采暖前有机碳占比（达51.9%）最高，非采暖期元素碳占比（32.6%）最高.采暖期有机碳、高分子有机物和左旋葡聚糖占比明显高于非采暖期，元素碳、矿物质和重金属反之.③ 停暖前后首要的两类污染源为燃煤和机动车尾气，二者贡献率之和分别高达70.1%和67.4%，可见本地主要受这两类源的影响.燃煤在采暖期为首要污染源，并且贡献比例高于非采暖期，而机动车尾气在非采暖期为首要污染源，且比例明显高于采暖期.研究显示，采暖和非采暖期虽然首要污染源有所差异，但在污染过程中，机动车尾气源的贡献比例均高于优良时段，说明无论是采暖期还是非采暖期，除燃煤排放的影响外，机动车尾气的影响也需得到重视，建议加强机动车燃油品质的升级，使用清洁煤，并在重污染时段采取相应的管控措施. 

Sources and Components of PM2.5 in Ambient Air of a Typical Living Quarter in Taiyuan City before and after Stopping Heating based on Single Particle Aerosol Mass Spectrometry

A single particle aerosol mass spectrometer (SPAMS) was used to analyze the sources and chemical characteristics of PM_2.5 in a typical living quarter of Taiyuan City during heating (March 11^th-18^th, 2016) and non-heating (April 1^st-7^th, 2016) periods. The results showed that:(1) Intensities of organic carbon (OC), sulfate and polycyclic aromatic hydrocarbons (PAHs) during the heating period were higher than during the non-heating period, while intensities of elemental carbon (EC), nitrate and ammonium were opposite. (2) Particles under the same wind scale during the same period were chosen to exclude the effects of meteorological factors. The results showed that OC, internally mixed organic and elemental carbon (ECOC) and EC were the main components during the two periods, and OC was dominant during the heating period (51.9%), while EC was dominant during the non-heating period (32.6%). Proportions of OC, high molecular weight organic matter (HOC) and levoglucosan (LEV) during the heating period were higher than those during the non-heating period, while proportions of EC, mineral dust and heavy metal (HM) showed an opposite trend. (3) The two main pollution sources during the heating period and the non-heating period were both coal combustion and vehicle exhaust, the sum of which contributed 70.1% and 67.4% to the total particles during the heating and non-heating periods, respectively. Coal combustion was the primary source during the heating period, while vehicle exhaust was the primary source during the non-heating period. The results showed that although the primary sources during heating and non-heating periods differed a lot, the proportion of vehicle exhaust increased significantly during both periods, indicating that vehicle emissions should be treated more carefully during both periods. Corresponding measures should be implemented, such as petrol quality upgrading, using clean coal and other controlling strategies, during heavy pollution periods.