LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
Sci Total Environ. 2009 Dec 20;408(2):312-7. doi: 10.1016/j.scitotenv.2009.07.010. Epub 2009 Oct 24.
The concentration, composition, and variability of nonmethane hydrocarbons (NMHCs) and carbon monoxide (CO) were characterized in a suburban region of south-central China. Weekly samples were collected in 2007 in the Changsha suburban area and analyzed with a three-stage preconcentration method coupled with GC-MS. A time series of NMHC measurements showed seasonal variation, with a higher level occurring in winter and a lower level in summer. Toluene was the most abundant species with an average concentration of 2.51+/-1.87 ppbv, followed by benzene (2.04+/-1.30 pptv). According to the level of identified NMHCs, vehicular exhaust appears to be the main source of NMHCs in Changsha. Among alkanes, the highest level is propane with a concentration of 1.31+/-0.71 ppbv, it indicated an extensive use and leakage of liquefied petroleum gas (LPG) in Changsha. The concentrations of NMHCs were influenced by the wind direction; a high level of NMHCs was carried by winds from southern China. Significant biogenic isoprene emissions were observed, with good correlation between isoprene level and temperature. Finally, when the typical individual NMHC species and CO in the morning and afternoon were compared, the shorter lifetime of NMHC species relative to CO could explain the poorer correlation observed in the afternoon.
本研究对中国中南部一个郊区的非甲烷碳氢化合物（NMHCs）和一氧化碳（CO）的浓度、组成和变化进行了研究。于 2007 年在长沙郊区每周采集一次样品，并用 GC-MS 耦合的三级预浓缩方法进行分析。NMHC 的时间序列测量结果显示出季节性变化，冬季浓度较高，夏季浓度较低。甲苯是最丰富的物种，平均浓度为 2.51+/-1.87 ppbv，其次是苯（2.04+/-1.30 pptv）。根据鉴定出的 NMHCs 的水平，机动车尾气似乎是长沙 NMHCs 的主要来源。在烷烃中，丙烷的浓度最高，为 1.31+/-0.71 ppbv，表明长沙广泛使用和泄漏液化石油气（LPG）。NMHCs 的浓度受风向影响；来自中国南方的风携带高浓度的 NMHCs。观察到显著的生物源异戊二烯排放，异戊二烯水平与温度之间存在良好的相关性。最后，当比较早晨和下午典型的单个 NMHC 物种和 CO 时，NMHC 物种相对于 CO 的较短寿命可以解释下午观察到的较差相关性。
