Characteristics of Non-Methane Hydrocarbons in the Atmosphere of Guangzhou
From March to December 2005 NMHCs were measured in an urban site in Guangzhou. Air samples were collected with canister and analyzed for HMHCs by GC-MSD/FID after cryogenic pre-concentration. Mixing ratios of Alkanes accounted for over 43% in total NMHCs in each month while the shares of aromatic hydrocarbons were 19-28%. In average ethyne was the most abundant compound (5.46 ppbv), followed by propane (4.49 ppbv) and toluene (4.19 ppbv). Seasonal variations of most anthropogenic hydrocarbons revealed higher mixing ratios in autumn-winter than in spring-summer. Isoprene, on the contrary, exhibited the the highest levels in summer and the lowest in spring. Anthropogenic NMHCs typically showed a first peak around 8:00 local time in morning and 20:00 local time in the evening, while isoprene revealed a different bimodal diurnal pattern.
L. F. Li and X. M. Wang, "Characteristics of Non-Methane Hydrocarbons in the Atmosphere of Guangzhou", Applied Mechanics and Materials, Vols. 66-68, pp. 59-64, 2011