摘要
[目的]研究山西省太原市秋冬季生物质燃烧和采暖燃煤对大气细颗粒物(PM2.5)质量浓度及化学成分的影响.[方法]使用武汉天虹公司TH-150C中流量大气PM2.5采样器于2014年10月4日至11月23日在山西大学环境科学研究所楼顶采集大气PM2.5样品,测定其重金属、水溶性无机离子和有机碳(OC)、元素碳(EC)含量,记录采样期间气温、相对湿度、风速、大气PM2.5日均浓度值,并查阅同期太原市周围卫星火点图.[结果]卫星火点图显示,2014年10月下旬太原市周边火点明显多于11月,与之相联系,采样点大气PM2.5质量浓度呈现10月高、11月前2周低、之后快速上升的趋势,与该趋势变化相一致的是PM2.5中的无机水溶离子SO24-、NO3-、NH4+、K+、重金属元素Zn、Pb、As以及含碳颗粒OC、EC,而F-、Cl-和重金属Cd、Ni却呈现缓慢累积的变化规律,Na+、Mg2+、Ca2+浓度变化幅度较小,说明PM2.5的来源复杂,影响因素较多;与采暖前相比,采暖后NO3-和SO24-质量浓度比以及OC/EC均下降,表明采暖燃煤可使大气中SO2和EC的排放迅速增加.[结论]太原市大气PM2.5质量浓度及化学成分受多种因素的影响,除气象因素和燃煤外,生物质燃烧是重要的贡献源,城市周边生物质大量燃烧甚至可以超过采暖燃煤对大气PM2.5浓度的影响.
Abstract
[Objective] The aim was to study the influences of biomass and coal burning in autumn and winter on the mass concentrations and components of ambient fine particulate matter over Taiyuan,Shanxi Province.[Method] The PM2.5 samples were collected every day on a fivestory building at Shanxi University using a medium-volume PM2.5 impactor from Oct.4,2014 to Nov.23,2014.The heavy metals,water-soluble inorganic ions,and organic carbon (OC) and elemental carbon (EC) in all PM2.5 samples were detected,respectively.The air temperature,relative humidity,wind speed during sarnphng were recorded and the daily concentration of atmospheric PM2.5 and satellite fire point figure surrounding the sampling site were obtained from corresponding websites.[Result] The fire points near the city in late Oct.were much more than those in Nov..Correspondingly,the concentration of atmospheric PM2.5 was high in Oct.and low in first two weeks of Nov.,and then was increased rapidly.Most of components in PM2.5 such as inorganic soluble ions SO24-,NO3-,NH4+,K +,heavy metal elements Zn,Pb,As,and carbonaceous particles OC and EC were consistent with the change trend of PM2.5 concentration,but the contents of F-,Cl-,Cd,Ni,Cu which were increased slowly from Oct.to Nov.and Na+,Mg2+ and Ca2+ which were relatively constant during sampling,had a different trend.It was illustrated the complex sources of PM2.5 and multiple affecting factors.Both the ratio of NO3-and SO24-concentration and the value of OC/EC were decreased in November in comparison with the results before heating,indicating coal burning contributed a lot to the rapid increase of airbome SO2 and EC.[Conclusion] The variations of the PM2.5 concentration and chemical compositions in Taiyuan City are attributed to many factors.In addition to meteorological factors and coal combustion,anthropogenous biomass burning plays an important role in PM2.5 pollution,even having more influence than coal burning to a large extent.
国家科技期刊平台
NSTL
维普
万方数据