基于高分辨率MARGA分析太原市春季PM_(2.5)化学组成特征

Analysis of the chemical composition characteristics of PM_(2.5) in spring in Taiyuan based on high resolution MARGA

为研究太原市城区春季PM_(2.5)的化学组成特征,于2020年3月对PM_(2.5)及其化学组分(水溶性离子和碳组分)、气态污染物(SO_(2)和NO_(2))进行在线监测,结合气象条件,分析了优良天和污染天PM_(2.5)的化学组成特征。结果表明,太原市城区PM_(2.5)总水溶性离子质量浓度范围是2.14μg/m^(3)~122.53μg/m^(3),平均值22.96μg/m^(3),在PM_(2.5)中占比53.81%,其中,SNA含量最高,在PM_(2.5)中占比55.99%和TWSIIs的78.82%,OC和EC分别占16.83%和1.95%,说明SNA和碳组分是PM_(2.5)的主要组成;相关性分析表明,二次离子主要存在形式是(NH4)_(2)SO_(4)和NH_(4)NO_(3),OC/EC比值大部分均在2.5~10.5之间,说明燃煤源是含碳气溶胶的主要来源;SNA和OC/EC浓度与相对湿度均呈现显著正相关,与气压均呈现显著负相关。

In order to study the characteristics of the chemical composition of PM_(2.5) in spring in Taiyuan and the influences of regional transportation, PM_(2.5) and its chemical components(watersoluble ions and carbon components), gaseous pollutants(SO_(2), NO_(2)) were monitored by online instruments in March 2020, combined with meteorological conditions, the chemical composition characteristics of PM_(2.5) were analyzed in fine weather and polluted weather. The results show that the total water-soluble ion concentration of PM_(2.5) in the urban area of Taiyuan city is 2.14 μg/m^(3)~122.53 μg/m^(3), with an average value of 22.96 μg/m^(3), accounting for 53.81% of PM_(2.5). The highest content is SNA, accounting for 55.99% of ρ(PM_(2.5)) and 78.82% of TWSIIs, among the carbon components, OC and EC accounted for 16.83% and 1.95% of ρ(PM_(2.5)) respectively, indicating that SNA and carbon components are the main components of PM_(2.5). Correlation analysis shows that the main form of secondary ions is(NH4)_(2)SO_(4) and NH_(4)NO_(3). Most of the OC/EC ratios are between 2.5 and 10.5, indicating that coal-burning sources are the most important source of carbon-containing aerosols. SNA and OC/EC concentrations are related to relative humidity showed a significant positive correlation, and both showed a significant negative correlation with average air pressure.