成都城区冬季一次灰霾期间PM_1化学成分特征

Study on Chemical Composition Characteristics of PM_1 during a Haze Period in Winter of Chengdu Urban Area

为了研究成都城区冬季典型灰霾天气条件下PM_1的主要化学成分和污染特征,于2016年1月1日至7日发生灰霾天气期间对大气中PM_1进行采样测定,首先考察了灰霾天气期间的PM_1质量浓度变化,然后分析了PM_1化学成分中Al、As、Ca、Fe、K、Mg、Mo、Se、Zn、Ti、Li等11种无机元素和Cl^-、NO^(3-)、SO_4^(2-)、NH^(4+)、K^+、Ca^(2+)等6种无机离子以及OC、EC等碳组分的变化情况。结果表明:灰霾期间PM_1平均质量浓度高达109.74μg/m3,是相对非污染天气的1.84倍;Ca、Fe元素平均浓度高,变化趋势大;SO_4^(2-)、NO^(3-)、SO_4^(2-)等二次水溶性无机离子在离子浓度总和中占比高达87.43%,其中NO^(3-)/SO_4^(2-)的值为0.75;OC为TC中的主要成分,OC/EC的平均值为3.5,SOC对OC的贡献率为46%。以上结果说明典型灰霾天气条件下成都城区PM_1中无机元素、水溶性无机离子和TC浓度显著增加;建筑扬尘、土壤风沙尘是主要污染源,固定源的贡献大于移动源;灰霾发生期间PM_1中二次气溶胶生成量明显升高。

In order to analyze the mass concentration change tendency of main chemical composition and pollution characters of PM1 in Chengdu urban area under the typical winter haze weather,we have acquired samples of PM1（Particulate Matter） in the atmosphere from January 1 st,2016 to 7 th,which is in a period time of haze weather. Firstly,observe the change tendency of the mass concentration of PM1,and then analyze the change tendency of 11 inorganic elements,which are Al、As、Ca、Fe、K、Mg、Mo、Se、Zn、Ti、Li,and 6 inorganic ions,which are Cl^-、NO^（3-）、SO4^（2-）、NH^（4＋）、K^＋、Ca^（2＋）,and the change tendency of OC,EC. The result show that the average concentration of PM1 is up to 109.74 μg/m3 during haze,which is 1.84 times compared with non polluted weather. Moreover,the average concentration of Ca and Fe are high along with great change tendency. Secondary water-soluble inorganic ions（SO4^（2-）、NO^（3-）、NH^（4＋）） in the total ion concentration accounted as high as 87.43 %,of which the value of NO^（3-）/SO4^（2-） is 0.75. OC（Organic Carbon） is the main component of TC（Total Carbon）. What is more,the average value of OC/EC（Elemental Carbon） is 3.5,and the contribution rate of SOC（Secondary organic carbon） to OC is 46 %. The results above illustrate that haze weather and winter weather condition cause the concentration of PM1,inorganic elements,water-soluble inorganic ions and TC increased significantly in Chengdu urban area. The principle pollution sources are construction dust and soil sand dust,and the fixed pollution sources contributed more than mobile pollution sources. There is a obvious increase on secondary aerosol generating quantity.