China's SO2 emission reductions enhance atmospheric ozone-driven sulfate aerosol production in East Asia

• 成果类型: Article
• 署名作者: Lin, Yu-Chi; Zhao, Yan; Zhang, Yan-Lin; Hong, Yihang; Hattori, Shohei; Itahashi, Syuichi; Fan, Mei-Yi; Xie, Feng; Zhao, Zhu-Yu; Yu, Mingyuan; Cao, Fang; Xu, Rongshuang; Li, Jianghanyang; Kawamura, Kimitaka; Thiemens, Mark H.
• 署名单位: Nanjing University of Information Science & Technology; Nanjing University of Information Science & Technology; Nanjing University; Nanjing University; Kanazawa University; Kyushu University; University of Colorado System; University of Colorado Boulder; National Oceanic Atmospheric Admin (NOAA) - USA; Chubu University; University of California System; University of California San Diego
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12445
• DOI: 10.1073/pnas.2414064122
• 发表日期: 2025-06-17
• 关键词: anthropogenic emissions; chemical-composition; mount tai; MODEL; pyrolysis; pathways; nitrate; sulfur; region; quartz

摘要

Reduction of China's SO2 emissions has been found to nonlinearly decrease the atmospheric sulfate (SO42-) aerosol concentrations in East Asia. Compared to Europe and North America, the lower effectiveness of SO42-reduction in East Asia suggested much effects of acidity-sensitive feedback mechanisms in this high anthropogenic emission region, which have not been yet examined. In this work, we investigated these feedback mechanisms in East Asia through long-term measurements of the mass-independent oxygen-17 anomaly (017O) in sulfate aerosols, machine learning and Community Multiscale Air Quality (CMAQ) model. As China's emissions reduced, the atmospheric acidity decreased, enhancing the ozone-driven oxidation of S(IV) and production efficiency of sulfate formation. This explained the weaker declining SO42-concentrations than SO2 emissions. By the evidence from observed 017O in non-sea-salt sulfate (017O-nss-SO42-) and CMAQ simulations, the highly enhanced contributions of S(IV)+O3 to sulfate driven by reduced SO2 emissions explained the low effectiveness of SO42-reduction in East Asia. Additionally, the decreases of acidity by substantial NH3 emissions are projected to continue until 2050, limiting SO42-reduction effectiveness. Thus, we highlighted that global control of both SO2 and NH3 emissions are needed to efficiently mitigate the sulfate-related climate and pollution, especially in high NH3 emission region, such as East Asia.