Characteristics And Environmental Effects Of Atmospheric Volatile Organic Compounds In Typical Areas Of Shandong

In recent years,with the accelerated economic development in Shandong region,the type of air pollution has gradually changed to regional and compound type,and haze pollution and ozone pollution have intensified.Volatile organic compounds（VOCs）are regarded as precursors for the formation of secondary organic aerosols（SOA）and O₃,have attracted more and more attention.In order to study the pollution characteristics and environmental effects of VOCs in Shandong,the provincial capital Jinan and the industrially developed city Zibo were selected for continuous online monitoring of atmospheric VOCs to analyze the VOCs concentration characteristics,sources,health risk assessment,SOA generation potential,ozone generation potential and L_·OHcontribution,and the environmental effect assessment of the two places using the entropy method.The sources and distribution of major pollutant emissions in Shandong can be understood,so that control policies and emission reduction measures can be targeted to achieve the goal of reducing pollutant emissions and improving air quality.（1）In this study,the highest contribution of alkanes was found at the Jinan site,followed by halohydrocarbons,OVOCs,and alkenes.The dominant species in Jinan’s atmosphere are mainly C2～C5 alkanes and alkenes,chloromethane,and acetylene,etc.OVOCs are the main contributing components in Zibo site,and the concentration level of VOCs in Zibo is significantly higher than that in Jinan due to the influence of industrial parks.Temporal variation,the daily variation of TVOCs in Jinan showed an increasing trend at night（18:00-06:00）,peaking at the morning peak（8:00-9:00）,followed by a gradual decrease in concentration to the trough（16:00）during the day due to enhanced photochemical reactions.alkanes,halohydrocarbons and acetylene,and the gaseous pollutant NO_xshow similar daily variation trends as TVOCs.The Zibo site is affected by industrial production patterns and morning and evening traffic emissions,and the daily variation of VOCs shows a pattern of high night and low day.VOCs at the Zibo site mostly peak during the dawn hours（3:00-6:00）,which may be due to the accumulation of pollutants from individual enterprises in the industrial park during the night.（2）The comprehensive determination of VOCs sources in Jinan by the characteristic species ratio analysis and PMF model revealed that traffic emissions are the main source of atmospheric VOCs in Jinan,and industrial sources and combustion emissions also have an important influence on the concentration of atmospheric VOCs in Jinan.Most of the characteristic species ratios in Zibo are within the industrial emission interval,indicating that industrial emissions contribute more to VOCs in this region.（3）The health risk evaluation showed that the non-carcinogenic risk in Jinan was negligible,and the non-carcinogenic risk to the exposed population at the Zibo site was non-carcinogenic,with acrolein as the main non-carcinogenic species,followed by propanal;the carcinogenic risk in both cities exceeded the safety threshold recommended by EPA,with1,2-dichloroethane and 1,2-dichloropropane as the main carcinogenic species at the Jinan site,and 1,2-dichloropropane as the main carcinogenic species at the Zibo site,followed by1,3-butadiene and naphthalene.（4）The ozone generation potential,OH depletion rate and secondary organic aerosol generation potential at the Zibo site were all higher than those at the Jinan site.The largest contributing species of L_·OHand OFP at Jinan site were alkenes,followed by alkanes and aromatics,while OVOCs were the main contributing components of OFP and L_·OHat Zibo site,followed by aromatics and alkenes.Aromatics in the two cities contributed most significantly to SOA and were the priority control components.（5）In this study,the control levels of VOCs species in the two cities were graded by the entropy value method,and then a comprehensive environmental assessment was conducted.The priority control pollutants in Jinan are toluene,m/p-xylene,and benzene,and the priority control pollutants in Zibo site are benzaldehyde and propanal.Combined with the results of the comprehensive environmental assessment,aromatic hydrocarbons are the components that have the greatest impact on the comprehensive environmental effect in the two cities,and are the components that need to be controlled with priority in the two cities.