宿州市冬季PM_(2.5)中水溶性离子化学特征分析

Chemical Characteristics of Water-Soluble Ions of PM_(2.5) in Winter in Suzhou

利用宿州市2022年12月1日至2023年2月28日PM_(2.5)及其水溶性离子连续观测数据分析了宿州市冬季PM_(2.5)中水溶性离子化学特征。结果表明:宿州市冬季PM_(2.5)污染较重,且各个监测点位浓度水平差异较小。NO_(3)^(-)、NH_(4)^(+)和SO_(4)~2是PM_(2.5)中总水溶性离子主要的组成部分,三者之和占比达到86.0%。NH_(4)^(+)易与NO_(3)^(-)和SO_(4)^(2-)结合形成NH_(4)NO_(3)、(NH_(4))_(2)SO_(4)或者NH_(4)HSO_(4)。Ca^(2+)和Mg^(2+)相关性较高,说明宿州市PM_(2.5)可能受扬尘影响;Cl^(-)与K^(+)(生物质燃烧的指示离子)的相关性较好,说明宿州市PM_(2.5)受到生物质燃烧的影响。宿州市大气中存在明显的二次转化过程;NO_(3)^(-)/SO_(4)^(2-)比值显示移动源对宿州市PM_(2.5)的贡献较高。OC和EC是PM_(2.5)中主要组成部分且来源相同。

The chemical characteristics of water-soluble ions in PM_(2.5) in winter in Suzhou were analyzed based on the continuous observation data of PM_(2.5) and its water-soluble ions from December 1,2022 to February 28,2023.The results showed that the pollution of PM_(2.5) in Suzhou was serious in winter,and the concentration of PM_(2.5) in different monitoring sites had little difference.NO_3~-,NH_4~+ and SO_4~(2-) were the main components of total water-soluble ions in PM_(2.5),and the sum of them accounted for 86.0%.NH_4~+,NO_3~-and SO_4~(2-) mainly existed in the form of NH_4NO_3,(NH_4)_2SO_(4) or NH_4HSO_4.The high correlation between Ca~(2+) and Mg~(2+) indicated that PM_(2.5) in Suzhou might be affected by airborne dust,and the correlation between Cl~-and K~+,the indicator ion of biomass combustion was good,indicating that PM_(2.5) in Hong Kong was affected by biomass combustion.There was an obvious secondary transformation process in the Suzhou atmosphere,and the NO_3~-/SO_4~(2-) ratio showed that the contribution of mobile sources to PM_(2.5) in Suzhou was higher.OC and EC were the major components of PM_(2.5) and come from the same source.