Significant impact of carbonates on the concentration and light absorption properties of black carbon in Lanzhou, northwest China

IF 3.9 3区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Atmospheric Pollution Research Pub Date : 2025-02-19 DOI:10.1016/j.apr.2025.102473

Xiaoxiang Wang , Shichang Kang , Zhaofu Hu , Chao Zhang , Fangping Yan , Pengfei Chen , Yicheng Wang

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Abstract

The concentrations of organic carbon (OC) and elemental carbon (EC, also known as black carbon) are often overestimated by carbonates during the thermal-optical measurement, leading to an underestimation of EC's light absorption ability, especially in northwest China. To investigate this influence, a comparison between untreated and acid-treated total suspended particle (TSP) samples was investigated in Lanzhou. The overestimation of EC concentration due to acid treatment was approximately 17.47 ± 1.09 %. After correction, the overestimations of OC and EC concentrations by carbonates were approximately 9.26 ± 10.76 % and 19.68 ± 14.34 %, respectively. This overestimation of EC concentration by carbonates was highest in spring, driven by dust storms, and lowest values in winter, revealing a contrasting trend to atmospheric temperature. The actual concentrations of OC and EC in Lanzhou were the lowest in summer and highest in winter, respectively. OC/EC ratios and EC concentrations overestimated by carbonates were significantly positively correlated, indicating that mineral dust played an important role in the composition of carbonaceous aerosols, especially during spring dust storm. After correcting for the overestimated EC concentrations, the mass absorption cross-section of EC (MAC_EC) in untreated samples was only about 72.97 ± 11.48 % of that in acid treated samples at 660 nm, indicating a significant underestimation of MAC_EC values due to carbonates. This study provides the first investigation of actual carbonaceous aerosols concentrations and MAC_EC values in northwest China, providing a more accurate understanding for the climatic effects of carbonaceous aerosols.

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碳酸盐对兰州地区黑碳浓度及光吸收特性的显著影响

有机碳（OC）和元素碳（EC，又称黑碳）的浓度在热光学测量中经常被碳酸盐高估，导致对EC的光吸收能力低估，特别是在中国西北地区。为了研究这种影响，对兰州地区未经处理和酸处理的总悬浮粒子（TSP）样品进行了比较。酸处理对EC浓度的高估约为17.47±1.09%。校正后，碳酸盐对OC和EC浓度的高估值分别约为9.26±10.76%和19.68±14.34%。由于沙尘暴的影响，碳酸盐对EC浓度的高估在春季最高，在冬季最低，这与大气温度的变化趋势相反。兰州市OC和EC的实际浓度夏季最低，冬季最高。OC/EC比值与碳酸盐高估的EC浓度呈显著正相关，表明矿物粉尘在含碳气溶胶组成中发挥了重要作用，特别是在春季沙尘暴期间。在校正高估的EC浓度后，在660 nm处，未经处理的样品中EC的质量吸收截面（MACEC）仅为酸处理样品的72.97±11.48%，表明由于碳酸盐的影响，MACEC值被严重低估。本研究首次对西北地区碳质气溶胶的实际浓度和MACEC值进行了调查，为更准确地了解碳质气溶胶的气候效应提供了依据。

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来源期刊

Atmospheric Pollution Research ENVIRONMENTAL SCIENCES-

CiteScore

8.30

自引率

6.70%

发文量

256

审稿时长

36 days

期刊介绍： Atmospheric Pollution Research (APR) is an international journal designed for the publication of articles on air pollution. Papers should present novel experimental results, theory and modeling of air pollution on local, regional, or global scales. Areas covered are research on inorganic, organic, and persistent organic air pollutants, air quality monitoring, air quality management, atmospheric dispersion and transport, air-surface (soil, water, and vegetation) exchange of pollutants, dry and wet deposition, indoor air quality, exposure assessment, health effects, satellite measurements, natural emissions, atmospheric chemistry, greenhouse gases, and effects on climate change.