摘要
基于西安市霾污染时段(2022年12月29日-2023年1月13日)在线连续观测数据,分析了两个污染过程(污染过程Ⅰ:2022年12月29日-2023年1月6日;污染过程Ⅱ:2023年1月7日-1月13日)VOCs特征及日变化;利用特征比值法和正交矩阵因子分解法(PMF)解析了霾污染期间VOCs来源;通过气溶胶生成系数法(FAC)估算了二次有机气溶胶(SOA)生成潜势。结果表明:污染过程Ⅰ和Ⅱ的体积分数分别为(113.10±29.46)×10^(-9)、(95.23±21.40)×10^(-9),含氧有机物和烷烃二者占比70%以上。与清洁天相比,芳香烃的增幅最大,含氧有机物增长值最大,炔烃类减少,说明气团老化严重,积累效应明显。过程Ⅱ烷烃下降,反映了启动重污染天气预警减排效果明显。日变化呈夜高昼低,9时左右有个小高峰特征;特征比值法分析得出VOCs中的苯和甲苯来源于溶剂使用源,PMF模型源解析结果显示VOCs主要来机动车排放源(20.54%)、外部传输源(19.02%)、餐饮源(13.99%)、工业溶剂源(10.72%)、工业过程源(35.72%);通过估算SOA生成潜势,得出芳香烃中的苯系物(BTEX)和萘为SOA污染的主要物质。
The characteristics,aging degree and diurnal variation of VOCs in two haze pollution processes(pollution process I:from December 29,2022 to January 6,2023;Pollution Process II:from January 7,2023 to January 13,2023)were analyzed,based on the continuous on-line observation data of haze pollution period at the Xi'an Super Station(December 29,2022-January 13,2023).The sources of VOCs during haze pollution episode were analyzed by characteristic ratio method and orthogonal matrix factorization(PMF).The formation potential of secondary organic aerosols(SOA)was estimated by the method of aerosol formation coefficient(FAC).Result showed that the volume concentration of VOCs were(113.10±29.46)×10^(-9),and(95.23±21.40)×10^(-9) in heavy pollution process I and II.The proportion of organic compounds and alkanes was more than 70%.Compared to the situation in the clean days,aromatic hydrocarbons showed the largest increase,Oxygenated Organic Compounds(OOCs)showed the largest increase in value,and acetylenic hydrocarbons showed a decrease indicating a significant cumulative effect of severe aging of the air mass.In Process II alkanes declined,reflecting the significant emission reduction effect of activating the heavy weather warning.The diurnal variation was high at night and low at day,with a small peak at about 09:00.The analysis of characteristic ratio shows that benzene and toluene in VOCs come from the source of solvent,the source apportionment results of PMF model showed that VOCs mainly came from vehicle exhaust(20.54%),external imported sources(19.02%),food sources(13.99%),industrial solvent sources(10.72%),and industrial production sources(35.72%).By estimating the SOA generation potential,it was concluded that the benzene series compounds(BTEX)and naphthalene in aromatic hydrocarbons were the main substances of SOA pollution.
作者
薛兴钊
陈妙
李顺姬
曹泽磊
张军
杨檬
Xue Xingzhao;Chen Miao;Li Shunji;Cao Zelei;Zhang Jun;Yang Meng(Xi'an Academy of Environmental Protection Sciences,Xi'an 710062,China;Xi'an Environmental Monitoring Station,Xi'an 710100,China)
出处
《环保科技》
2024年第4期27-33,共7页
Environmental Protection and Technology
关键词
霾污染
挥发性有机物(VOCs)
特征比值法
源解析
二次有机气溶胶(SOA)
heavy pollution episode
volatile organic compounds(VOCs)
characteristic ratio method
source resolution
secondary organic aerosol(SOA)
