| 机动车源大气颗粒物粒径分布及碳组分特征 |
| 摘要点击 2555 全文点击 989 投稿时间：2018-07-10 修订日期：2018-07-20 |
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| 中文关键词 大气颗粒物 机动车 粒径 碳组分 热光碳分析 |
| 英文关键词 atmospheric particulate matter motor vehicles size carbon component thermal/optical carbon |
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| 中文摘要 |
| 颗粒物的粒径分布特性与碳质组分的表征已成为大气颗粒物源解析的重要方法.利用微孔均匀沉积式碰撞采样器与有机碳/元素碳分析仪，研究采集自不同区域的机动车源大气颗粒物粒径分布特性及其碳组分含量特征.结果表明，随着粒径级增大，发动机原排颗粒物质量浓度逐渐降低.实验室排空大气颗粒物在0.32~0.56 μm粒径级浓度较高；地下停车场大气颗粒物在1.0~1.8 μm粒径级浓度较高.柴油机原排颗粒物OC1、OC2和OC3所占比例较多，EC2为元素碳的主要部分.机动车源扩散区域大气颗粒物OC3和OC4含量所占比例较多，地下停车场大气颗粒物EC1占元素碳绝大部分.柴油机原排颗粒物的OC/EC比值较小，在0.92~2.50之间.实验室排空与地下停车场大气颗粒物的OC/EC比值分别在1.40~2.53与2.36~4.82之间.此外，地下停车场大气颗粒物的OC/EC比值均大于2.0，最高可达4.82，可以判定地下停车场有较多的二次颗粒物生成.上述特性可为机动车源大气颗粒物的辨识提供参考依据. |
| 英文摘要 |
| Characterization of the size distribution and carbon components in particulates has become important for identifying the particulates in the atmosphere. The size distribution and carbon components of atmospheric particulate matter from motor vehicles in different regions were analyzed by using Micro-orifice uniform deposition impactors (MOUDI) and the organic carbon/elemental carbon (OC/EC) analyzer. With increasing particle size, the mass concentration of raw diesel/gasoline decreases. The highest mass concentration of particles collected near the chimney of an engine laboratory was observed for particle sizes ranging from 0.32-0.56 μm, while particles with sizes from 1.0-1.8 μm in the basement garage showed the most mass fractions. The OC1, OC2, and OC3 were the major parts of the OC contents in raw diesel particles. The EC2 was the main part of EC. The atmospheric particles collected in typical regions contained more OC3 and OC4. EC1 was the main part of EC in particles collected from the basement garage. The OC/EC ratios of raw diesel particles ranged from 0.92 to 2.50. The OC/EC ratios of particles collected near the chimney of an engine laboratory ranged from 1.40 to 2.53 and that of particles collected in the basement garage ranged from 2.36 to 4.82. Moreover, the OC/EC ratios in particles collected in the basement garage normally exceeded 2.0 and reached 4.82 at the largest size, which implies that many secondary particles were generated in the basement garage. The above-mentioned characteristics provide references that are beneficial for the identification of particulates in the atmosphere originating from motor vehicles. |
