Characteristics and sources of Volatile Organic Compounds in urban Jinan,China
To study the characteristics and sources of ambient volatile organic compounds(VOCs)in urban Jinan,monthly offline observations from 2020 to 2021 and intensive observations in June 2020 were conducted.The inter-annual,seasonal,and daily concentration changes,chemical composition,and ozone formation potential(OFP)of VOCs were analyzed.Sources of VOCs were analyzed using the tracer ratio method and positive matrix factorization(PMF)model.The results indicated that the annual average mixing ratio of VOCs in urban Jinan in 2021 was(35.70±16.58)×10-9,an improvement of 14.48%compared to 2020,with alkanes and oxygenated VOCs(OVOCs)were the two major components of VOCs.The seasonal characteristics of the average mixing ratio of VOCs in 2020 showed a high in winter and a low in summer,while in 2021,it showed an increase in summer and a low in spring.Influenced by the special rectification action of VOCs in Jinan and the air quality assurance measures for the Beijing Winter Olympics,the average mixing ratio of VOCs in winter 2021 improved significantly compared to 2020,with an improvement rate of 31.08%.Aromatic hydrocarbons contributed significantly in the spring of 2020,which might be related to enterprises'gradual resumption of work under epidemic control.The top ten components in 2020 and 2021 are mainly alkanes and OVOCs,such as propane,ethane,n-butane,formaldehyde,acetone,and acetaldehyde.The annual value of OFP was 239.39µg/m3 in 2021,a decrease of 22.46%compared to 2020.The improvement rates of OFP for alkanes,alkynes,aromatics,and halogenated hydrocarbons were 29.28%,3.09%,67.93%,and 83.49%,respectively.The OFP for olefins increased significantly,with an increase rate of 37.49%.OVOCs remained at a relatively high level.The top ten species in OFP rankings in 2020 and 2021 mainly include formaldehyde,acetaldehyde,ethylene,1-butene,propylene,and para/meta xylene.During heavy ozone pollution episodes,the daily variation characteristics of TVOCs volume fraction showed obvious morning and evening peak characteristics,with the noon period being the low value of the day and maintaining a high level at night.The PMF analysis showed that VOCs mainly came from industrial sources,combustion sources,oil and gas volatilization,motor vehicle exhaust emissions,solvent use sources,plant emissions,and secondary generation sources.Motor vehicle exhaust emissions,combustion sources,and industrial sources were critical sources of VOCs for O3 pollution control in Jinan.
万方数据
维普
