基于稳定化学组分高分辨率粒径谱的大气颗粒物来源解析方法研究

The traditional source apportionment approaches of particulate matter, such as CMB and PMF, are difficult to verify in reality and not timely. In view of these problems, this research devoted to establish a new PM source apportionment approach based on the high size-resolved profile of stable chemical species that can be obtained by the development of sampling techniques. The detailed work includes: 1) screening the stable chemical species which have the source identification function and keep stability of characteristics such as morphology, particle size distribution, 2) establishing the stable chemical species profile with high particle size resolution of particulate matter sources and environmental receptors, respectively, 3) setting up source apportionment approach based on the stable chemical composition particle size distribution, and comparing the result with traditional receptor model in order to validate each other..Since a large number of chemical species (nearly 30 kinds of chemical composition） should all be analyzed in traditional model of PM source apportionment but not in this work, so the analysis error can be effectively controlled and the analysis time can shorten, the interference for analyze results caused by uncertainty of many kinds of chemical composition analysis method could be reduced. Besides, the research scope of traditional source chemical profile will be expanded due to the particle size-resolved information which is an important physical characteristic of particulate matter is added. The comparing of source apportionment results obtained by this technique and the traditional model could provide the possibility to verify the rationality of the source apportion results from the physical meaning. Another important application of this technique is to provide a rapidly source apportionment result in the heavy pollution process.

本研究针对传统大气颗粒物源解析模型中存在的解析结果难以验证及时效性不强等问题，结合采样技术的最新发展，通过对源和受体进行同步分粒径多级采样和传统单一粒径采样，筛选识别在源与受体间的传输过程中保持形态、粒径分布等特征稳定的化学组分，建立污染源与环境受体颗粒物中稳定化学组分的高分辨率粒径谱，将粒径分布特征这一重要信息纳入源解析技术体系，建立基于稳定化学组分粒径分布特征的大气颗粒物来源解析方法，并与单一粒径采样的传统源解析结果进行比较验证。此方法无需分析大量化学物种，可缩短分析时间，降低多种化学成分分析方法的不确定性对解析结果的干扰。将粒径信息纳入源解析技术体系，可扩充传统源成分谱内涵，解析结果可作为传统源解析结果的有效验证，为从物理意义上验证源解析结果的合理性提供了可能；在重污染过程应急等对解析结果时效性要求比较高的情景下，基于粒径特征的解析方法可作为一种较为快速的方法提供及时的解析结果。

利用静电低压多级冲击式采样器（ELPI，芬兰Delka）对典型燃煤电厂、供热厂、扬尘、机动车尾气尘、钢铁厂、生物质燃烧源和散煤燃烧源样品进行了分级采集，此外，利用ELPI连续采集不少于一周的环境受体颗粒物样品，共获得分粒径的源和受体颗粒物样品602个，对采集的源和受体颗粒物样品进行实验室平衡、称重以及化学组分的化学分析，获取有效数据8000余个。对各化学组分的多粒径源谱进行分析，发现Ca/Fe/V/Zn/Cu等化学组分在污染源间的粒径分布具有明显差异。进一步对组分在污染源间粒径分布差异性进行评估发现Cu的差异性最显著，构建出Cu的污染源粒径谱。基于Cu在污染源间的粒径分布特征，建立了基于Cu的粒径分布信息的化学质量平衡模型（Size-resolved chemical mass balance model, SR-CMB），继而成功解析出污染源对颗粒物浓度的贡献。通过将其与基于中流量采样器采集的PM10的传统CMB模型解析结果进行对比，发现两者解析结果可比，且对二次颗粒物的估算一致。模拟实验结果显示，源贡献的波动主要由添加的噪声引起，SR-CMB解析结果稳定。.本研究将特定化学组分粒径信息纳入受体模型，为传统受体模型解析结果的验证提供了新的角度和依据；由于可依据单一化学组分Cu的粒径分布信息开展解析运算，可大幅减少颗粒物全组分化学分析的需求，避免了前处理环节缩短分析过程，同时也降低了多种化学分析方法的不确定性对解析结果的干扰，可为时效性要求较高的重污染过程的来源解析提供及时有效的解决思路。