| Due to the decisive role of atmospheric oxidative properties,identify the Volatile organic compounds(VOCs)regional characteristics and sources has great impacts on accurately identify the atmospheric pollution characteristics,causes of regional air pollution and set up regional air pollution prevention,respectively.Based on in-situ observation at Hohhot-Baotou-Bayannur urban agglomeration in Inner Mongolia Autonomous Region,a total number of 117 kinds of VOCs were identified to study their regional and chemical characteristics and sources.The main results were as follows:1.Baotou and Hohhot TVOCs concentrations were higher in winter,with OVOCs and alkanes share the most.Ethane,propane,ethylene,acetylene,formaldehyde,acetone and benzene share the dominant parts of alkanes and OVOCs.Winter atmospheric TVOCs was lower in Bayannur with alkanes share the most.2.Coal combustion vehicle exhaust and transmission had great impacts on atmospheric VOCs concentrations in both Hohhot,Baotou and Bayannur.Besides,LPG/NG also contribute atmospheric VOCs in Hohhot and Baotou during summertime.Baotou and Bayannur also greatly affected by industrial emissions,solvent volatilization and combustion sources.3.Little difference between winter and summer at transmission monitoring sites were observed with ethane,acetylene,ethylene,n-butyraldehyde,formaldehyde,propane,acetone and ios-pentane sharing the most fractions.The source analysis suggested the vehicle exhaust,LPG/NG,solvent volatilization and industrial sources were the major sources.4.The key photochemical active species of VOCs in the study area were propane,ethylene,propylene,isoprene,acetaldehyde,propionaldehyde,n-butyraldehyde,toluene and m/p-xylene,respectively.The OFP values of atmospheric VOCs in the study area in winter were larger than those in summer,while the LOH values were opposite.The chemical reactivity of VOCs in Baotou is the strongest in winter,and ozone generation is more sensitive to VOCs concentration;in summer,the chemical reactivity of VOCs in urban area of Bayannur City is the strongest,and ozone generation is more sensitive to NO2 concentration. |
