The impact of atmospheric new particle formation on air quality
- 1University of Helsinki, Institute for Atmospheric and Earth System Research / Physics, Finland
- 2Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
- 3Joint International research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, China
- *A full list of authors appears at the end of the abstract
Large fractions of atmospheric aerosols, both locally and globally, relevant to air quality and climate are produced via new particle formation (NPF; Kerminen et al., 2018; Chu et al., 2019; Kulmala et al., 2021). Kulmala et al. (2021) showed that NPF and secondary aerosol formation contribute to over 2/3 of the haze particle number and over 80% of the corresponding mass in Beijing.
We combine the following tools to find out physical and chemical mechanisms of atmospheric NPF: i) targeted laboratory experiments, ii) comprehensive in situ observations, iii) comprehensive vertical observations, iv) satellite remote sensing and v) multi-scale modelling.
We investigated a closure on sub-6 nm atmospheric aerosol particles and clusters showing that present observations can detect a major fraction of existing atmospheric clusters (Kulmala et al. 2022a). Our second finding, based on long-term measurements in four very different environments, was that even on days traditionally considered as non-event days (no observed NPF), “quiet NPF” occurs with formation rates between 2–20% of traditional NPF event days (Kulmala et al. 2022b). Thirdly, we investigated the growth of newly-formed particles into sizes relevant to climate and air quality using simulations in two different environments: 1) Beijing, a megacity in China, and 2) SMEAR II station, a boreal forest in Finland. Our simulations for Beijing showed that NPF is capable of giving large contributions of haze particle mass and number concentrations (Kulmala et al. 2022c). The results indicate that reducing primary particle emissions may not decrease PM pollution effectively in heavily polluted environments without simultaneous reductions for precursor gases responsible for NPF and subsequent particle growth. At SMEAR II, we simulated the role of NPF in the Continental Biosphere-Atmosphere-Cloud-Climate (COBACC) feedback mechanism (Kulmala et al. 2023). We found that outside the periods when NPF events tend to be rare at SMEAR II, NPF gives a dominant contribution to both condensation sink and cloud condensation nuclei concentration – the two most relevant quantities in the COBACC feedback mechanism. As a side product of our observations, we found surprisingly low variability in growth rates of newly formed particles in both Beijing and SMEAR II. This points toward a potentially important role of multiphase reactions causing the bulk growth of newly formed atmospheric particles – a phenomenon that needs to be investigated in more detail in the future.
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T. Kokkonen1, R. Cai1, C. Yan1,2,3, D. Stolzenburg1,4, L. Dada1,5, P. Paasonen1, W. Nie3, J. Cai1, W. Du1, E. Ezhova1, J. Kangasluoma1, K. Lehtipalo1,6, F. Bianchi1, A.-M. Sundström6, T. Petäjä1, D. Worsnop1, U. Pöschl7, H. Su7,8, J. Tamminen6, I. Salma9, H. Junninen10, A. Ding3, Y. Cheng7 and V.-M. Kerminen1
How to cite: Kulmala, M. and the Working group: The impact of atmospheric new particle formation on air quality, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-935, https://doi.org/10.5194/ems2024-935, 2024.
