Characteristics,sources Of Carbonyl Compounds And Analysis Of Ozone Formation Sensitivity In Zibo City

Carbonyl compounds are very important VOCs in the atmosphere.As the intermediate products of photochemical reactions,they make a great contribution to the formation of free radicals,ozone and secondary organic aerosols.In recent years,as ozone pollution has become more and more serious,carrying out research on atmospheric carbonyl compounds has important practical significance.Research areas in this study was in Zibo City,Shandong.DNPH（2,4-dinitrophenylhydrazine）offline sampling method was used to conduct sampling of carbonyl compounds at the Zhonglou urban site and Lushan site in the spring,summer,autumn and winter simultaneously;and the SUMMA canisters offline sampling method was used to conduct sampling of carbonyl compounds and NMHCs（Non-methane Hydrocarbons）at 3 sites（Tianzhen,Beijiao,Xindian）in summer.Based on the observation data,the characteristics,sources and ozone formation sensitivity to carbonyl compounds have been studied.The average concentration of total 15 carbonyl compounds urban site and background site were（10.41±4.91）and（7.90±3.69）ppbv.And the sum of formaldehyde,acetaldehyde and acetone accounted for 74%and 78%of the total carbonyl compounds in urban and background sites,respectively.Carbonyl compounds showed obvious peaks in the afternoon in both sites,and the concentration rose in the morning and evening rush hours.At two sites,the secondary formation dominated carbonyl compound concentrations in summer,and the primary contribution in winter was relatively large.As a background site,Lushan was also significantly affected by anthropogenic emissions.The results of comparison with other environments showed that the carbonyl concentration levels in Lushan was similar to other background sites,and the application of the species ratio method was extremely uncertain.The average TVOC concentration levels during the sampling period in summer at three sites of Tianzhen,Beijiao,and Xindian were（56.6±47.94）,（47.11±14.19）,（67.47±30.85）ppbv respectively.Carbonyl compounds of Beijiao and Xindian all contributed the largest proportion of OFP and L_OH.Alkenes accounted for the largest OFP in Tianzhen,and isoprene accounted for the largest L_OH in Tianzhen.The PMF results showed 5 factors,which were identified as natural sources,traffic related sources,oil and gas volatilization,secondary sources and background,industrial and solvent usage respectively.The sources of VOCs in Tianzhen,Beijiao and Xindian that accounted for the largest proportions were oil and gas volatilization,secondary sources and background,secondary sources and background,respectively.Analysis of ozone formation sensitivity shows that whether carbonyl compounds are added to the OBM model input data or not may change the determination of that ozone formation is more sensitive to VOCs or NO_x,and when excluded,the RIR of other VOCs will be overestimated.The RIR comparison of different AVOCs,VOCs from different sources showed that the ozone formation was sensitive to carbonyl compounds.The RIR of carbonyl compounds in traffic related sources,oil and gas volatilization were relatively high.In the environment where the secondary formation dominates VOCs concentration,ozone formation is more sensitive to carbonyl compounds.This study comprehensively studied the seasonal variation and sources of carbonyl compounds in urban and background sites,the characteristics of carbonyl compounds at multiple sites in urban areas in summer and whether carbonyl concentrations were added into OBM model input data or not will affect the ozone generation sensitivity analysis.This study can provide a scientific and technological support to the understanding of carbonyl compound pollution and atmospheric pollutant management and control strategies.