The Significant Role of New Particle Composition and Morphology on the HNO₃-Driven Growth of Particles down to Sub-10 nm

Journal Article · 13 March 2024 · Environmental Science and Technology

DOI: https://doi.org/10.1021/acs.est.3c09454 · OSTI ID:2510806

Li, Yuyang ^[1]; Li, Xiaoxiao  ^[2]; Cai, Runlong  ^[3]; Yan, Chao ^[4]; Zheng, Guangjie  ^[5]; Li, Yiran ^[1]; Chen, Yijing ^[1]; Zhang, Yusheng ^[6]; Guo, Yishuo ^[6]; Hua, Chenjie ^[6]; Kerminen, Veli-Matti ^[3]; Liu, Yongchun ^[6]; Kulmala, Markku ^[7]; Hao, Jiming ^[1]; Smith, James N.  ^[8]; Jiang, Jingkun  ^[1]

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1. Tsinghua Univ., Beijing (China)
2. Wuhan Univ. (China)
3. Univ. of Helsinki (Finland)
4. Univ. of Helsinki (Finland); Nanjing Univ. (China); Beijing Univ. of Chemical Technology (China)
5. Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry
6. Beijing Univ. of Chemical Technology (China)
7. Univ. of Helsinki (Finland); Beijing Univ. of Chemical Technology (China)
8. Univ. of California, Irvine, CA (United States)

New particle formation and growth greatly influence air quality and the global climate. Recent CERN Cosmics Leaving OUtdoor Droplets (CLOUD) chamber experiments proposed that in cold urban atmospheres with highly supersaturated HNO₃ and NH₃, newly formed sub-10 nm nanoparticles can grow rapidly (up to 1000 nm h^–1). Here, we present direct observational evidence that in winter Beijing with persistent highly supersaturated HNO₃ and NH₃, nitrate contributed less than ~14% of the 8–40 nm nanoparticle composition, and overall growth rates were only ~0.8–5 nm h^–1. To explain the observed growth rates and particulate nitrate fraction, the effective mass accommodation coefficient of HNO₃ (α_HNO3) on the nanoparticles in urban Beijing needs to be 2–4 orders of magnitude lower than those in the CLOUD chamber. We propose that the inefficient uptake of HNO₃ on nanoparticles is mainly due to the much higher particulate organic fraction and lower relative humidity in urban Beijing. To quantitatively reproduce the observed growth, we show that an inhomogeneous “inorganic core–organic shell” nanoparticle morphology might exist for nanoparticles in Beijing. Finally, this study emphasized that growth for nanoparticles down to sub-10 nm was largely influenced by their composition, which was previously ignored and should be considered in future studies on nanoparticle growth.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Atmospheric Radiation Measurement (ARM) Data Center
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Contributing Organization: Argonne National Laboratory (ANL); Brookhaven National Laboratory (BNL); Pacific Northwest National Laboratory (PNNL)
• Grant/Contract Number: SC0021208
• OSTI ID: 2510806
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 12 Vol. 58; ISSN 0013-936X
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English