Study on Pollution Characteristics of Atmospheric VOCs and Ozone Generation in Autumn in Urumqi
VOCs are important precursors for the formation of O3.Reactive substances undergo photochemical reactions under favorable meteorological conditions,which directly affect the level of ozone pollution,which directly affect the level of ozone pollution.In this paper,based on the observations of VOCs concentration in the atmosphere of Urumqi from September to November 2021,the temporal change characteristics of VOCs composition in autumn were analyzed,the impact potential of each component on ozone formation was compared,and the PMF receptor model method was used to analyze the main sources of VOCs.The results showed that the total concentration of VOCs in September was 29.31 nmol/mol,the total concentration of VOCs in October was 34.20 nmol/mol,and the total concentration of VOCs in November was 48.38 nmol/mol,showing a raising trend month by month,among which alkanes accounted for the highest proportion,followed by oxygenated organics,alkynes,alkenes,halogenated hydrocarbons,aromatic hydrocarbons and sulfides.The main contributors to oxygen formation potential were acetaldehyde and m/p-xylene.Other major substances for oxygen formation potential,such as acetaldehyde,m/p-xylene,ethylene,propylene,1-butene,p-xylene,made outstanding contributions every month.During this period,coal combustion contributed the most to the concentration of VOCs in Urumqi atmosphere,followed by vehicle exhaust and petrochemical industry,with contribution ratios of 25.9％,16.4％and 15.4％,respectively.
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