南京江北化工园区挥发性有机物走航观测

MOBILE MEASUREMENT OF AMBIENT VOLATILE ORGANIC COMPOUNDS IN THE JIANGBEI CHEMICAL INDUSTRIAL PARK OF NANJING,CHINA

挥发性有机物(VOCs)是大气中1类具有较大健康危害的污染物,同时也是大气中二次有机气溶胶和臭氧生成的重要前体物。首次使用搭载了单光子电离质谱仪(SPI-MS)的走航观测车,在2018年3月对南京江北化工园区环境空气中的VOCs进行了为期4 d的走航观测。观测期间,总VOCs的平均浓度为133.3μg/m^(3),夜间平均浓度(143.6μg/m^(3))较日间(123.1μg/m^(3))偏高,工作日平均浓度(226.7μg/m^(3))远高于周末(39.9μg/m^(3))。同时还获得了高时间和高空间分辨率的VOCs分布特征,并详细分析了走航路线途经的3个重点区域(南钢-南化、扬子石化和化工大道区域)的特征污染物、浓度变化及主要排放源(企业)。总体来看,VOCs组成以烷烃和芳香烃浓度占比最大(均为31%),其次为烯烃(25%)和卤代烃(13%);但对臭氧生成潜势的贡献,则是烯烃最大(56%),其次为芳香烃、烷烃和卤代烃,分别占32%、9%和3%。该结果为化工园区VOCs的减排管理及区域臭氧污染控制提供参考。

Volatile organic compounds(VOCs)are a group of air pollutants with potentially adverse health effects,and also important precursors of both secondary organic aerosols and ozone.In this work,an online single photon ionization mass spectrometer(SPI-MS)was installed on a vehicle,and for the first time,we conducted a four-day mobile measurement of VOCs in the Nangjing Jiangbei Chemical Industry Park during March 2018.During the sampling period,the average concentration of total VOCs was 133.3μg/m^(3),nighttime mean concentration(143.6μg/m^(3))was higher than that during daytime(123.1μg/m^(3)),and mean mass concentration of workdays(226.7μg/m^(3))was found to be much higher than that of weekend(39.9μg/m^(3)).We also obtained highly time-and spatially-resolved distributions of VOCs,and elucidated the characteristic species,and variations and dominant sources(factories)of the three key zones(Nangang Nanhua,Yangzi Shihua,and Huagong Dadao).Overall,alkanes and aromatics were the major contributors(both 31%)of the total VOCs,followed by alkenes(25%)and halocarbons(13%);while in terms of ozone formation potential,alkenes was the largest contributor(56%),followed by aromatics(32%),alkanes(9%)and halocarbons(3%).Our findings here could provide useful insights and guidances into the VOCs reduction measures and local ozone pollution control.