Application Of PMF Model In The Source Apportionment Of VOCs In Industrial Area

As an important precursor of photochemical smog,volatile organic compounds（VOCs）have become one of the main culprits of urban haze.Based on the long-term VOCs monitoring data of an industrial area in Shaoxing,this study investigated the main VOCs emission sources in the industrial area and surrounding areas,calculated the contribution of different emissions by using the model,and analyzed the temporal and spatial changes of VOCs emission.Finally,according to the results of field investigation and model calculation,the impact of atmospheric VOCs on the surrounding environment and human health were further calculated.On the whole,the pollution of VOCs in the northern industrial area of Shaoxing is improving year by year.From the specific components of VOCs,dichloromethane and toluene accounted for a relatively high proportion in the regional atmospheric VOCs concentration.It can be seen that the emission sources of solvent use,pharmaceutical production and chemical production in the industrial area contribute a lot.PMF model calculation results showed that the contribution rate of VOCs emission sources of the industrial area in 2016 was 26%for petrochemical industry,19%for solvent use,18%for specific industrial sources,16%for oil and gas volatilization,13%for automobile exhaust and 8%for plant emission.Among them,the top three industrial VOCs emission sources accounted for 63%.Combined with the measurement results around the enterprises,the local specific industrial sources dominated by pharmaceutical and printing and dyeing enterprises accounted for 18%,which was one of the main VOCs emission sources in Paojiang new area.In general,the emission intensity and contribution rate of various VOCs sources have obvious seasonal variation.In summer,oil and gas volatilization was the main method,and in winter,solvent was the main method.The source strength and contribution rate of petrochemical industry were relatively stable,accounting for about a quarter.The contribution of plant emissions was more obvious in summer.According to the calculation of ozone generation potential,aromatics,alkenes and aldehydes contributed a lot to ozone generation during heavy haze,and olefins accounted for 51%of the total contribution.The contribution of toluene,acetone and acetaldehyde to the secondary organic aerosol generation potential（SOA）of VOCs was relatively high.The SOA value calculated by VOCs active components had a good correlation with the concentration of PM_2.5.During heavy haze,the highest SOA/PM_2.5 ratio can reach 9.2%.This indicates that the contribution of VOCs to the secondary particulate matter was significant during the combined pollution period.In addition,although olefin concentration was not high,it played an important role in the formation of regional atmospheric ozone.