荆门市PM_(2.5)中碳组分污染特征及二次有机碳评估

Carbon Composite Pollution Characteristics and Second Organic Carbon Evaluation of PM_(2.5) in Jingmen City

为研究荆门市PM_(2.5)中碳组分不同季节污染特征及二次有机碳生成,于2021年6月至2022年5月进行了为期1年的细颗粒物碳组分采样监测。利用OCEC分析仪对其质量浓度进行了分析,并利用最小相关系数法(MRS)对二次有机碳(SOC)进行了评估,结果显示:荆门市PM_(2.5)中TC均值为10.9μg/m^(3),占PM 2.5的14.2%,其中OC均值为8.8μg/m^(3),EC均值为2.1μg/m^(3);不同季节碳组分污染特征显示冬季OC、EC浓度水平最高,春夏季最低,而占比特征正好相反,说明相比冬季,春夏季碳组分对PM_(2.5)贡献较大;相关性及比值分析显示春季OC和EC相关性较好,夏季的相关性最差,OC/EC均值为4.5,符合机动车尾气及燃煤复合污染特征,各季节均存在不同程度的二次有机污染过程;SOC评估结果显示SOC对OC贡献春季>夏季>冬季>秋季。

In order to study the characteristics of different seasons of carbon components in Jingmen City PM_(2.5) and the production of secondary organic carbon,it carried out one year of fine particulate carbon component sampling monitoring from June 2021 to May 2022.The OCEC analyzer analyzed its quality concentration and used the minimum correlation coefficient(MRS)to evaluate the secondary organic carbon(SOC).It accounts for 14.2% of PM_(2.5),of which the average value of OC is 8.8μg/m^(3),and the average value of the EC is 2.1μg/m^(3);the pollution characteristics of carbon components in different seasons show the highest level of OC and EC in winter,the lowest in spring and summer.The characteristics of the proportion are the opposite,indicating that compared with winter,the carbon components in spring and summer have contributed greater contributions to PM_(2.5);correlation and ratio analysis shows that the correlation between Spring OC and EC is better.The average value of EC is 4.5,which is in line with the characteristics of motor vehicle exhaust gas and coal-fired composite pollution.There are different degrees of organic pollution processes of different degrees of organic pollution in each season;the SOC evaluation results show that SOC contributes to OC in spring>winter>autumn.