Emission Characteristics And Their Environmental Impacts Of 2017-based Anthropogenic NO_x And VOCs In Zhengzhou

Complex air pollution with ozone(O3)and fine particle matter(PM2.5)is a key factor,which restricts the current air quality in China.As the precursor,it’s indispensable to develop the emissions of nitrogen oxides(NOx)and volatile organic compounds(VOCs).In this thesis,the emission inventories of NOx and VOCs and their impact on the atmospheric environment were analyzed in Zhengzhou City as the study area,with a view to providing basic data support for local air quality improvement.Firstly,based on the field investigation and official statistical data to collect the activity levels and emission factors,then a county-level emission inventory of anthropogenic NOx and VOCs was established in 2017.The ArcGIS technology was used to conduct a high-resolution spatial distribution(1 km×1km)of emissions.The results showed that the total emission of NOx in Zhengzhou was 132.3 kt,and on-road mobile(53.6%)was the main contribution source,and Dengfeng and Xingyang were the high emission areas,accounting for 26.2%and 18.3%,respectively.The total VOCs emission was 134.6 kt,and the industrial process(38.5%)was the main contribution source,and Gongyi and Xinzheng were the high emission areas,accounting for 25.7%and 12.3%,respectively.NOx and VOCs emissions reached the highest value in June,accounting for 9.2%and 9.0%of the whole year,respectively.High emission values canbe found in the the main urban areas and their surrounding areas with concentrated industries.Secondly,based on the collected source profiles,the VOCs speciated emission inventory was established in Zhengzhou in 2017.The results showed that the higher VOC components were alkanes,aromatic hydrocarbons and oxygen-containing VOCs.For industrial process source,on-road mobile source and solvent utilization source,there were 18,29 and 26 species with an emission ratio more than 1.0%,respectively.The species with largest emissions for the three sources mentioned above were styrene,toluene and m/p-xylene,accounting for14.3%,6.0%and13.1%,respectively.At the same time,based on the speciated inventory of VOCs,the ozone formation potential(OFP)and secondary organic aerosol formation potential(SOAP)of Zhengzhou were evaluated in 2017.The results showed that the total OFP in Zhengzhou was 406.9 kt,with aromatic hydrocarbon and alkene as higher contributor,and on-road mobile source and solvent utilization source were the higher contribution sources,accounting for 31.1%and 22.5%,respectively.The total SOAP was 12.3 kt,with alkane and aromatic hydrocarbon as higher contributor,and the industrial process source,solvent utilization source nd on-road mobile source were the higher contribution sources,accounting for 54.7%,18.1%and 14.0%,respectively.The district and county with the highest contributions to both OFP and SOAP in Zhengzhou was Gongyi City.Finally,based on the above research,the key control species for VOCs in Zhengzhou were m/p-xylene,o-xylene,toluene,benzene propylene,styrene and ndodecane,and the key emission sources were construction solvents and asphalt paving.