Black carbon and iron oxide aerosols measured in the East Asian and Arctic regions in 2009-2019.

Black carbon (BC) and light-absorbing iron oxides (FeOx) aerosols affect Earth's energy budget through their strong absorption of solar radiation. FeOx aerosols also can play a role as a nutrient for oceanic phytoplankton and thus potentially affects the global biogeochemical cycles. However, in-situ observation data of atmospheric concentrations and microphysical properties of these light-absorbing aerosols which are required for evaluating their climate effects using global models have been scarce, especially for FeOx aerosols. Here, we summarize and compare the datasets of BC and light-absorbing FeOx from five ground and three aircraft observation campaigns conducted in the East Asian and Arctic regions during the 2009-2018 period by using a modified single-particle soot photometer of the University of Tokyo. In all the campaigns, the majority (> 80%) of FeOx-containing aerosols in 170-270 nm FeOx size range has microphysical features of anthropogenic origin. The particle-size distribution for each of the BC and FeOx was similar among all the datasets, excepting the datasets dominated by fresh urban pollution or pristine arctic free-tropospheric air. The campaign-averaged mass concentration of FeOx (BC) in the East Asian and Arctic regions were ~100-400 (~300-1000) ng/m3 and ~5 (~25) ng/m3, respectively. Despite the large inter-campaign variation of their mass concentration, the campaign-averaged FeOx/BC mass concentration ratio were within a quite narrow range of 0.2-0.5 for all the campaigns. In each campaign, FeOx, BC, and carbon monoxide (CO) were tightly correlated with each other, implying the similarity of spatial distribution of their emission sources.黑碳（Black carbon, BC）与吸光铁氧化物（light-absorbing iron oxides, FeOx）气溶胶通过强烈吸收太阳辐射，影响地球能量收支。FeOx气溶胶还可作为海洋浮游植物的营养源，进而潜在影响全球生物地球化学循环。然而，利用全球模型评估这类吸光气溶胶的气候效应所需的、其大气浓度与微物理性质的原位观测数据一直较为匮乏，针对FeOx气溶胶的此类数据尤为稀缺。本研究整理并对比了2009-2018年间，在东亚与北极区域开展的5项地面观测与3项机载观测项目所获取的BC与吸光FeOx数据集，所有观测均采用东京大学改进型单颗粒黑碳光度计完成。在所有观测项目中，粒径范围为170~270 nm的含FeOx气溶胶中，超过80%具有人为源的微物理特征。除了以新鲜城市污染气团或清洁北极自由对流层空气为主的数据集外，所有数据集的BC与FeOx各自的粒径分布均较为相似。东亚与北极区域的观测项目平均FeOx（BC）质量浓度分别约为100~400（300~1000）ng/m³与~5（25）ng/m³。尽管不同观测项目间的质量浓度存在较大差异，但所有项目的观测平均FeOx/BC质量浓度比值均处于0.2~0.5的狭窄区间内。在每个观测项目中，FeOx、BC与一氧化碳（carbon monoxide, CO）三者之间均存在显著相关性，这表明其排放源的空间分布具有相似性。