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 (δ¹³C) 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). δ¹³C values of NMHCs in the urban areas of Lanzhou and Taiyuan range from −32.3% to −22.3% and from −32.8% to −18.1‰ δ¹³C 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. Supported by National Natural Science Foundation of China (Grant No. 40673004)