Water-soluble low molecular weight organics in cloud water at Mt. Tai Mo Shan, Hong Kong

Wanyu Zhao; Zhe Wang; Shuwen Li; Linjie Li; Lianfang Wei; Qiaorong Xie; Siyao Yue; Tao Li; Yiheng Liang; Yele Sun; Zifa Wang; Xiangdong Li; Kimitaka Kawamura; Tao Wang; Pingqing Fu

doi:10.1016/j.scitotenv.2019.134095

Water-soluble low molecular weight organics in cloud water at Mt. Tai Mo Shan, Hong Kong

Sci Total Environ. 2019 Dec 20:697:134095. doi: 10.1016/j.scitotenv.2019.134095. Epub 2019 Aug 26.

Authors

Wanyu Zhao¹, Zhe Wang², Shuwen Li³, Linjie Li³, Lianfang Wei³, Qiaorong Xie³, Siyao Yue³, Tao Li⁴, Yiheng Liang⁵, Yele Sun⁶, Zifa Wang⁶, Xiangdong Li⁵, Kimitaka Kawamura⁷, Tao Wang⁵, Pingqing Fu⁸

Affiliations

¹ Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
² Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China. Electronic address: z.wang@ust.hk.
³ Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
⁵ Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
⁶ Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
⁷ Chubu Institute for Advanced Studies, Chubu University, Kasugai 487-8501, Japan.
⁸ Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China. Electronic address: fupingqing@tju.edu.cn.

PMID: 32380603
DOI: 10.1016/j.scitotenv.2019.134095

Abstract

Cloud-water samples collected at the summit of Mt. Tai Mo Shan (Mt. TMS, 957 m, a.s.l.), Hong Kong in autumn 2016 and spring 2017 were measured for molecular compositions and stable carbon isotope ratios (δ¹³C) of dicarboxylic acids, oxoacids and α-dicarbonyls. Oxalic acid (C₂, 253-1680 μg L^-1) was found as the most abundant diacid, followed by succinic acid (C₄, 24-656 μg L^-1) in autumn and phthalic acid (Ph, 27-363 μg L^-1) in spring. Higher concentrations of Ph (192 ± 197 μg L^-1) and terephthalic acid (tPh, 31 ± 15 μg L^-1) were observed in autumn than those in spring, illustrating the enhanced contribution from fossil fuel combustion and plastic wastes burning. Stronger correlations for the shorter chain diacids (C₂-C₄) with NO₃^-, nss-SO₄^2- and nss-K⁺ in autumn (R² ≥ 0.7) than spring suggested that these diacids were mainly produced via atmospheric photooxidation following anthropogenic emissions. The δ¹³C values of C₂ (mean - 14.7‰), glyoxylic acid (ωC₂, -12.2‰), pyruvic acid (Pyr, -15.5‰), glyoxal (Gly, -13.5‰) were much higher than those in atmospheric aerosols from isoprene and other precursors, indicating that diacids, oxoacids and α-dicarbonyls in cloud at Mt. TMS were significantly influenced by photochemical formation during the long-range atmospheric transport.

Keywords: Dicarboxylic acids; Mt. Tai Mo Shan; Seasonal cloud water; Stable carbon isotopic compositions.