邢台市冬季一次重污染过程PM_(2.5)污染特征分析

Analysis of PM_(2.5) pollution characteristics of a winter heavy pollution process in Xingtai City

为了解邢台市秋冬季重污染过程的污染特征,于2018年11月10—16日,在邢台市一中、内丘以及沙河3个点位采集PM_(2.5)样品,分析PM_(2.5)浓度及其化学组分。结果表明:重污染过程期间邢台市PM_(2.5)平均浓度为176.2μg/m^(3),超过GB 3095—2012《环境空气质量标准》二级标准限值1.4倍;水溶性离子以NO_(3)^(−)、SO_(4)^(2−)和NH_(4)^(+)为主,平均浓度分别为(32.3±13.4)、(16.4±9.0)和(15.0±6.8)μg/m^(3),分别占PM_(2.5)的18.3%、9.3%和8.5%,3种离子浓度在污染加重时较污染初期分别升高了0.8、2.3和1.2倍;OC平均浓度为(12.9±5.8)μg/m^(3),占PM_(2.5)的7.4%,EC平均浓度为(4.6±1.4)μg/m^(3),占PM_(2.5)的2.7%。邢台市该次重污染过程以二次污染为主导,主要受到燃煤及机动车排放影响较大。

In order to understand the pollution characteristics of heavy pollution process in Xingtai City in autumn and winter,PM_(2.5) samples were collected at three points in the city,including No.1 Middle School,Neiqiu and Shahe,during the pollution process on November 10-16,2018,to analyze the changes of PM_(2.5) concentration and chemical composition.The results showed that during the heavy pollution process,the average PM_(2.5) concentration of Xingtai City was 176.2μg/m^(3),which exceeded the secondary standard limit of Ambient Air Quality Standards(GB 3095-2012)by 1.4 times.The water-soluble ions were mainly NO_(3)^(−),SO_(4)^(2−)and NH_(4)^(+),with the average concentrations of(32.3±13.4),(16.4±9.0)and(15.0±6.8)μg/m^(3),which accounted for 18.3%,9.3%and 8.5%of PM_(2.5),respectively.The concentration of the three ions increased by 0.8,2.3 and 1.2 times when the pollution was aggravated compared with the initial stage of the pollution.The average concentration of OC was(12.9±5.8)μg/m^(3),accounting for 7.4%of PM_(2.5),and the average concentration of EC was(4.6±1.4)μg/m^(3),accounting for 2.7%of PM_(2.5).This pollution process in Xingtai City was dominated by secondary pollution,which was mainly affected by coal combustion and motor vehicle emissions.