Ma Li, Yu Ye, Wang Bo, Zhao Su-Ping, Li Gang
Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2017 Apr 8;38(4):1289-1297. doi: 10.13227/j.hjkx.201608156.
The purpose of this study was to investigate the characteristics and source apportionment of carbonaceous aerosols in PM for the daytime and nighttime during spring and summer over Lanzhou. The samples were collected from 1 April 2015 to 30 August 2015, daytime samples were collected during 08:00 to 20:00 and nighttime samples during 20:00 to 08:00 on the next day, and organic carbon (OC) and elemental carbon (EC) concentrations were measured. The results showed that PM, OC and EC concentrations were (136.0±84.3), (12.4±3.2), (2.3±0.7) μg·m during the daytime, and (196.0±109.2), (16.0±5.3), (5.0±2.1) μg·m during the nighttime. The mass concentrations of PM, OC and EC in the nighttime were higher than those during the daytime. The ratios of secondary organic carbon to total organic carbon were higher in the daytime than nighttime, suggesting that the secondary organic carbon pollution was more serious in the daytime. In sand-dust weather, the concentrations of PM and OC were higher than those in non-dust weather, while the EC concentration was close to that in non-dust weather. Secondary organic carbon and total carbon aerosols were higher in sand-dust weather, but the contribution to the PM was relatively low. In addition, principal component analysis on the eight carbon fractions of non-dust weather indicated that coal combustion, vehicle exhaust and biomass burning were the major sources for carbonaceous aerosol during the daytime, while coal combustion, dust, diesel exhaust and biomass burning played important roles in the nighttime.
本研究旨在调查兰州春夏季白天和夜间细颗粒物中碳质气溶胶的特征及来源解析。样品采集时间为2015年4月1日至2015年8月30日，白天样品在08:00至20:00采集，夜间样品在20:00至次日08:00采集，并测定了有机碳（OC）和元素碳（EC）浓度。结果表明，白天细颗粒物、有机碳和元素碳浓度分别为（136.0±84.3）、（12.4±3.2）、（2.3±0.7）μg·m，夜间分别为（196.0±109.2）、（16.0±5.3）、（5.0±2.1）μg·m。细颗粒物、有机碳和元素碳的质量浓度夜间高于白天。白天二次有机碳占总有机碳的比例高于夜间，表明白天二次有机碳污染更严重。沙尘天气下，细颗粒物和有机碳浓度高于非沙尘天气，而元素碳浓度与非沙尘天气相近。沙尘天气下二次有机碳和总碳气溶胶含量较高，但对细颗粒物的贡献相对较低。此外，对非沙尘天气下八个碳组分的主成分分析表明，白天煤燃烧、机动车尾气排放和生物质燃烧是碳质气溶胶的主要来源，而夜间煤燃烧、沙尘、柴油尾气排放和生物质燃烧起重要作用。
