Effects of NH3 and alkaline metals on the formation of particulate sulfate and nitrate in wintertime Beijing

Ru-Jin Huang; Jing Duan; Yongjie Li; Qi Chen; Yang Chen; Mingjin Tang; Lu Yang; Haiyan Ni; Chunshui Lin; Wei Xu; Ying Liu; Chunying Chen; Zhen Yan; Jurgita Ovadnevaite; Darius Ceburnis; Uli Dusek; Junji Cao; Thorsten Hoffmann; Colin D O'Dowd

doi:10.1016/j.scitotenv.2020.137190

Effects of NH₃ and alkaline metals on the formation of particulate sulfate and nitrate in wintertime Beijing

Sci Total Environ. 2020 May 15:717:137190. doi: 10.1016/j.scitotenv.2020.137190. Epub 2020 Feb 8.

Authors

Ru-Jin Huang¹, Jing Duan², Yongjie Li³, Qi Chen⁴, Yang Chen⁵, Mingjin Tang⁶, Lu Yang², Haiyan Ni⁷, Chunshui Lin⁸, Wei Xu⁸, Ying Liu⁹, Chunying Chen⁹, Zhen Yan¹⁰, Jurgita Ovadnevaite¹¹, Darius Ceburnis¹¹, Uli Dusek¹², Junji Cao², Thorsten Hoffmann¹³, Colin D O'Dowd¹¹

Affiliations

¹ Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth and Environment, Chinese Academy of Sciences, Xi'an 710061, China. Electronic address: rujin.huang@ieecas.cn.
² Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth and Environment, Chinese Academy of Sciences, Xi'an 710061, China.
³ Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau, China. Electronic address: yongjieli@um.edu.mo.
⁴ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China. Electronic address: qichenpku@pku.edu.cn.
⁵ Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
⁶ State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
⁷ Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth and Environment, Chinese Academy of Sciences, Xi'an 710061, China; Centre for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen (ESRIG), University of Groningen, the Netherlands.
⁸ Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth and Environment, Chinese Academy of Sciences, Xi'an 710061, China; School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland.
⁹ CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Centre for Nanoscience and Technology, Beijing 100191, China.
¹⁰ Metrohm China Ltd., Shanghai 200335, China.
¹¹ School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland.
¹² Centre for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen (ESRIG), University of Groningen, the Netherlands.
¹³ Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, Mainz 55128, Germany.

PMID: 32062279
DOI: 10.1016/j.scitotenv.2020.137190

Abstract

Sulfate and nitrate from secondary reactions remain as the most abundant inorganic species in atmospheric particle matter (PM). Their formation is initiated by oxidation (either in gas phase or particle phase), followed by neutralization reaction primarily by NH₃, or by other alkaline species such as alkaline metal ions if available. The different roles of NH₃ and metal ions in neutralizing H₂SO₄ or HNO₃, however, are seldom investigated. Here we conducted semi-continuous measurements of SO₄^2-, NO₃^-, NH₄⁺, and their gaseous precursors, as well as alkaline metal ions (Na⁺, K⁺, Ca²⁺, and Mg²⁺) in wintertime Beijing. Analysis of aerosol acidity (estimated from a thermodynamic model) indicated that preferable sulfate formation was related to low pH conditions, while high pH conditions promote nitrate formation. Data in different mass fraction ranges of alkaline metal ions showed that in some ranges the role of NH₃ was replaced by alkaline metal ions in the neutralization reaction of H₂SO₄ and HNO₃ to form particulate SO₄^2- and NO₃^-. The relationships between mass fractions of SO₄^2- and NO₃^- in those ranges of different alkaline metal ion content also suggested that alkaline metal ions participate in the competing neutralization reaction of sulfate and nitrate. The implication of the current study is that in some regions the chemistry to incorporate sulfur and nitrogen into particle phase might be largely affected by desert/fugitive dust and sea salt, besides NH₃. This implication is particularly relevant in coastal China and those areas with strong influence of dust storm in the North China Plain (NCP), both of which host a number of megacities with deteriorating air quality.

Keywords: Alkaline metals; Ammonia; Nitrate; Sulfate.