School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China; SKLLQG and KLACP, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an, 710061, China.
Max Planck Institute for Chemistry, Multiphase Chemistry Department, Hahn-Meitner-Weg 1, 55128 Mainz, Germany; Institute of Geography and Geoecology, Karlsruhe Institute of Technology (KIT), Reinhard-Baumeister Platz 1, 76131 Karlsruhe, Germany.
Environ Pollut. 2021 Jan 15;269:116148. doi: 10.1016/j.envpol.2020.116148. Epub 2020 Nov 24.
An improved understanding of the historical variation in the emissions and sources (biomass burning, BB vs. fossil fuel, FF combustion) of soot and char, the two components of black carbon (BC), and polycyclic aromatic compounds (PACs) may help in assessing the environmental effects of the Atmospheric Brown Cloud (ABC) in SE Asia. We therefore determined historical variations of the fluxes of soot, char, and PACs (24 polycyclic aromatic hydrocarbons (PAHs), 12 oxygenated PAHs (OPAHs), and 4 azaarenes) in a dated sediment core (covering the past ∼150 years) of Phayao Lake in Thailand. The soot fluxes have been increasing in recent times, but at a far lower rate than previously estimated based on BC emission inventories. This may be associated with a decreasing BB contribution as indicated by the decreasing char fluxes from old to young sediments. The fluxes of high- and low-molecular-weight (HMW and LMW) PAHs, OPAHs, and azaarenes all sharply increased after ∼1980, while the ΣLMW-/ΣHMW-PAHs ratios decreased, further supporting the reduction in BB contribution at the expense of increasing FF combustion emissions. We also suggest that the separate record of char and soot, which has up to now not been done in aerosol studies, is useful to assess the environmental effects of ABC because of the different light-absorbing properties of these two BC components. Our results suggest that besides the establishment of improved FF combustion technology, BB must be further reduced in the SE Asian region in order to weaken the ABC haze.
对烟尘和炭黑（BC）这两个组成部分以及多环芳烃（PACs）的排放和来源（生物质燃烧，BB 与化石燃料，FF 燃烧）在历史上的变化有了更深入的了解，可能有助于评估东南亚大气棕色云（ABC）对环境的影响。因此，我们在泰国的帕尧湖（Phayao Lake）的一个定年沉积物岩芯（涵盖过去约 150 年的时间）中测定了烟尘、炭黑和 PACs（24 种多环芳烃（PAHs）、12 种含氧多环芳烃（OPAHs）和 4 种氮杂芳烃）的通量在历史上的变化。烟尘通量最近一直在增加，但增加的速度远低于以前根据 BC 排放清单估计的速度。这可能与 BB 贡献的减少有关，这从旧沉积物到年轻沉积物的炭黑通量减少可以看出。高分子量（HMW）和低分子量（LMW）PAHs、OPAHs 和氮杂芳烃的通量在 1980 年后都急剧增加，而ΣLMW-/ΣHMW-PAHs 比值下降，进一步支持了 BB 贡献的减少，同时增加了 FF 燃烧排放。我们还提出，在气溶胶研究中迄今尚未单独记录烟尘和炭黑的通量，这对于评估 ABC 的环境影响是有用的，因为这两个 BC 组成部分的光吸收特性不同。我们的结果表明，除了建立改进的 FF 燃烧技术外，还必须在东南亚地区进一步减少 BB，以削弱 ABC 雾霾。
