Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100086, China.
Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Environ Sci (China). 2019 Jun;80:257-266. doi: 10.1016/j.jes.2019.01.002. Epub 2019 Jan 14.
Light-absorbing carbonaceous aerosols including black carbon (BC) and brown carbon (BrC) play significant roles in atmospheric radiative properties. One-year measurements of aerosol light absorption at multi-wavelength were continuously conducted in Xiamen, southeast of China in 2014 to determine the light absorption properties including absorption coefficients (σ) and absorption Ångström exponent (AAE) in the coastal city. Light absorptions of BC and BrC with their contributions to total light absorption were further quantified. Mean σ at 370 nm and 880 nm were 56.6 ± 34.3 and 16.5 ± 11.2 Mm, respectively. σ presented a double-peaks diurnal pattern with the maximum in the morning and the minimum in the afternoon. σ was low in warm seasons and high in cold seasons. AAE ranged from 0.26 to 2.58 with the annual mean of 1.46, implying that both fossil fuel combustion and biomass burning influenced aerosol optical properties. σ of BrC at 370 nm was 24.0 ± 5.7 Mm, contributing 42% to the total absorption. The highest AAE (1.52 ± 0.02) and largest BrC contributions (47% ± 4%) in winter suggested the significant influence of biomass burning on aerosol light absorption. Long-distance air masses passing through North China Plain and the Yangtze River Delta led to high AAE and BrC contributions. High AAE value of 1.46 in July indicated that long-range transport of the air pollutants from intense biomass burning in Southeast Asia would affect aerosol light absorption in Southeast China. The study will improve the understanding of light absorption properties of aerosols and the optical impacts of BrC in China.
吸光碳质气溶胶，包括黑碳（BC）和棕色碳（BrC），在大气辐射特性中起着重要作用。2014 年在中国东南部的厦门进行了为期一年的多波长气溶胶吸光测量，以确定沿海城市的吸光特性，包括吸收系数（σ）和吸收 Ångström 指数（AAE）。进一步量化了 BC 和 BrC 的吸光特性及其对总吸光的贡献。在 370nm 和 880nm 处的平均 σ 分别为 56.6±34.3 和 16.5±11.2Mm。σ呈现出双峰日变化模式，最大值出现在早晨，最小值出现在下午。σ 在温暖季节较低，在寒冷季节较高。AAE 范围从 0.26 到 2.58，年平均值为 1.46，这意味着化石燃料燃烧和生物质燃烧都影响了气溶胶的光学性质。在 370nm 处 BrC 的 σ 为 24.0±5.7Mm，占总吸收的 42%。冬季 AAE 最高（1.52±0.02）和 BrC 贡献最大（47%±4%）表明生物质燃烧对气溶胶吸光的显著影响。经过华北平原和长江三角洲的长距离气团导致了高 AAE 和 BrC 贡献。7 月 AAE 值高达 1.46 表明，来自东南亚强烈生物质燃烧的空气污染物的远距离输送将影响中国东南部的气溶胶吸光。该研究将提高对气溶胶吸光特性和 BrC 在中国光学影响的认识。
