基于气溶胶光学特性对武汉黑碳和有机碳的研究

Abstract

本文利用气溶胶的复折射指数首次反演得到武汉冬季黑碳和有机碳柱质量浓度。根据反演结果，我们得到武汉冬季气溶胶各组分中黑碳和有机碳所占的比例较小，黑碳所占比例均低于2%，有机碳略高于黑碳，所占比例在3%~10%。武汉2010年冬季黑碳的柱质量浓度均值为10.447 mg/m2，有机碳柱质量浓度的均值为25.406 mg/m2；2011年冬季黑碳的柱质量浓度均5.997 mg/m2，有机碳柱质量浓度的均值为15.259 mg/m2。根据BrC/BC的均值2.6，推测观测的气溶胶中含碳组分主要来自汽车尾气排放，与观测站点位于马路旁的实际情况相符。有机碳和黑碳不同的气溶胶复折射指数虚部假定会导致两者浓度的反演结果的不同，利用同步观测的黑碳仪数据，根据敏感性分析结果，得到黑碳的复折射指数假定为1.95/0.79最合理。 In this paper, we retrieved BC and BrC columnar content during winter in Wuhan, based on the aerosol complex refractive index for the first time. We found that BC and BrC accounted respectively for <2% and 3% - 10% of the total aerosol volume. The average columnar mass concentrations of BC and BrC in the winter of 2010 were 10.447 mg/m2 and 25.406 mg/m2, respectively; in the winter of 2011, they were 5.997 mg/m2 and 15.259 mg/m2, respectively. The BrC/BC ratio in Wuhan was about “2.6”, which indicates that the main source of city pollution is large-vehicle emissions caused by heavy traffic. According to the results from the sensitivity study, we suggest setting the complex refractive index of BC as m = 1.95 + 0.79i in Wuhan, to compare data with the synchronous observation of Aethalometer AE-31.