The carbon isotopic compositions of Non-methane Hydrocarbons in atmosphere

Carbon isotopic compositions of atmospheric Non-methane Hydrocarbons (NMHCs) in the urban areas of Taiyuan and Lanzhou in summer were reported and the sources of NMHCs are discussed. Carbon isotopic ratios (delta C-13) of vehicle exhaust, coal-combustion exhaust, fuel volatiles and cooking exhaust were also measured with thermal desorption-gas chromatography-isotope ratio-mass spectrometry (TD-GC-IR-MS). delta C-13 values of NMHCs in the urban areas of Lanzhou and Taiyuan range from -32.3% to -22.3% and from -32.8% to -18.1aEuro degrees delta C-13 values of vehicle exhaust, coal-combustion exhaust, fuel volatiles and cooking exhaust are -32.6--21.7%, -24.5%--22.3%, -32.5%--27.4% and -31.6%- -24.5%, respectively. The data indicate that vehicle exhaust and cooking exhaust make a significant contribution to the atmospheric NMHCs. Therefore, to reduce emissions of vehicle exhaust and cooking exhaust is critical for controlling atmospheric NMHCs pollution in summer.