Abstract
New particle formation has been estimated to produce more than half of the global cloud condensation nuclei and profoundly impacts clouds, climate, and air quality. The initial growth from the cluster size ( ~ 1 nm) to a few nanometers, for which the underlying mechanisms can be very different from the subsequent growth, is the most critical stage for new particles to become climate-relevant. However, initial growth mechanisms evidenced by controlled laboratory experiments can rarely explain observations from the real atmosphere. Here we show that a large nanoparticle concentration gradient in the size space can drive unexpected rapid initial growth based on measurements across the globe. It accelerates the condensation of globally abundant oxygenated organic molecules onto a population of new particles compared to a single particle, and substantially increases the fraction of new particles that survive to climate- and air-quality-relevant sizes. Our findings provide insights into explaining the puzzle of the frequent new particle formation events in polluted urban environments and indicate an even more important role of new particle formation in climate predictions.
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Data availability
The full dataset shown in the figures in the main text and supplementary materials is publicly available at https://doi.org/10.5281/zenodo.13761850.81
Code availability
The monodisperse aerosol growth model for growth rate from a volatility basis set of oxygenated organic molecules is publicly available at https://doi.org/10.5281/zenodo.13761850.81
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Acknowledgements
We thank the National Natural Science Foundation of China (grant no. 22406024, 22188102, 22127811), the ACCC Flagship funded by the Academy of Finland grant number 337549, the Academy professorship funded by the Academy of Finland (grant no. 302958), and the Academy of Finland projects. 332547, 325656, 311932, 334792, 316114, 325647, 325681, 333397, 328616, 357902, 345510, 347782, 346370, 364223, 325656, 356134, “Quantifying carbon sink, CarbonSink+ and their interaction with air quality” INAR project funded by Jane and Aatos Erkko Foundation, “Gigacity” project funded by Wihuri foundation, European Research Council (ERC) project ATM-GTP Contract No. 742206 and CHAPAs (grant No. 850614), European Union via Non-CO2 Forcers and their Climate, Weather, Air Quality and Health Impacts (FOCI), CRiceS (101003826), RI-URBANS (101036245), EMME-CARE (856612), FORCeS (821205), and NPF-PANDA (895875), European Commission grants INTEGRATE no. 867599, and Swedish Research Council grant no. 2023-03842. The Technology Industries of Finland Centennial Foundation, via the urbaani ilmanlaatu 2.0 project, is gratefully acknowledged. This work has been funded by the Vienna Science and Technology Fund (WWTF) through project VRG22-003. University of Helsinki support via ACTRIS-HY is acknowledged. Support of the technical and scientific staff at Hyytiälä and BUCT/AHL is acknowledged.
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R.C., D.W., J.J., M.K., and J.K. designed the research. R.C., X.L., Y.Li, D.S., Q.Z., J.Cai, W.N., C.Y., D.D.H., Z.W., J.W., R.Y., N.S., W.H., S.H., L.A., F.B., Y.Liu, and J.K. conducted experiments and collected data. R.C., X.L., Y.Li, and S.B. analyzed data. R.C., X.L., Y.Li, S.B., D.S., S.T., L.Y., A.D., F.B., P.W., T.P., J.Chen, V.-M. K., L.W., D.W., J.J., M.K., and J.K. contributed to the scientific discussion. R.C. wrote the manuscript with inputs from all co-authors.
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Cai, R., Li, X., Li, Y. et al. The key role of nanoparticle concentration gradient in aerosol initial growth. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70082-2
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DOI: https://doi.org/10.1038/s41467-026-70082-2
