{
  "abstract": "New particle formation (NPF) in the marine upper troposphere sustains one of the largest global aerosol reservoirs that seeds cloud condensation nuclei in the lower troposphere, with far-reaching implications for Earth’s radiative balance and climate. However, the underlying NPF mechanisms remain elusive, constituting a major uncertainty in climate projections. Here, we show that methanesulfonic acid (MSA), long considered only as a key boundary-layer precursor, dominates upper-tropospheric NPF across major oceans. Quantum-chemical and cluster dynamics simulations reveal that MSA enhances sulfuric acid (H 2 SO 4 )–ammonia (NH 3 ) nucleation rates by 1 to 3 orders of magnitude, far surpassing the well-established nitric acid (HNO 3 )–H 2 SO 4 –NH 3 mechanism, owing to stronger intracluster hydrogen bonds and low temperatures that stabilize clusters and render nucleation nearly barrierless. Further global three-dimensional modeling constrained by field measurements confirms that the proposed H 2 SO 4 –MSA–NH 3 nucleation pathway dominates the upper-tropospheric NPF over the Pacific, Atlantic, and Indian Oceans. Notably, this pathway contributes ~40% of global nucleation-induced Aitken- and accumulation-mode aerosols at 0.5 to 4 km altitudes, where most cloud water resides, and yields a net top-of-atmosphere radiation forcing of −1.75 W m −2 (~68% of the nucleation-induced response). This study offers a detailed mechanistic insight into marine upper-tropospheric NPF and improves representation of aerosol–cloud interactions, thereby reducing uncertainties in global climate projections.",
  "abstract_shown": true,
  "affiliations": [
    "State Key Laboratory of Environment Characteristics and Effects for Near-space, Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology",
    "State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex",
    "State Key Laboratory of Regional Environment and Sustainability, School of Environment, Tsinghua University",
    "Department of Chemistry, University of Zurich",
    "State Key Laboratory of Environmental Benchmarking and Risk Assessment, Chinese Research Academy of Environmental Sciences",
    "Department of Chemistry, University of Pennsylvania",
    "Department of Earth and Environmental Science, University of Pennsylvania"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Ning An",
      "orcid": "0000-0002-6530-4465"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "L.Y. Mao",
      "orcid": "0009-0009-2502-5857"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Bin Zhao",
      "orcid": "0000-0001-8438-9188"
    },
    {
      "affs": [
        0
      ],
      "name": "Haotian Zu"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Jiewen Shen",
      "orcid": "0009-0007-5638-9018"
    },
    {
      "affs": [
        3
      ],
      "name": "Yonggui Zhao"
    },
    {
      "affs": [
        0
      ],
      "name": "Jing Li"
    },
    {
      "affs": [
        0
      ],
      "name": "Xiucong Deng"
    },
    {
      "affs": [
        0
      ],
      "name": "Ling Liu",
      "orcid": "0000-0003-3719-4083"
    },
    {
      "affs": [
        4
      ],
      "name": "Haijie Zhang"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "Joseph S. Francisco",
      "orcid": "0000-0002-5461-1486"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "S S Wang",
      "orcid": "0000-0001-9727-1963"
    },
    {
      "affs": [
        0
      ],
      "name": "Xiuhui Zhang",
      "orcid": "0000-0001-9570-7882"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5ymmswkdp0nka.bib",
  "cited_by": 5,
  "doi": "10.1073/pnas.2606521123",
  "fulltext_url": null,
  "id": "5ymmswkdp0nka",
  "issns": [
    "0027-8424",
    "1091-6490"
  ],
  "landing_url": "https://doi.org/10.1073/pnas.2606521123",
  "language": "en",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1902|Atmospheric chemistry and aerosols"
    ]
  ],
  "openalex": "W7162770254",
  "pdf_url": null,
  "pmcid": "PMC13229238",
  "pmid": "42213761",
  "published": "2026-05-29",
  "publisher": "National Academy of Sciences",
  "ris": "https://research.draconitic.com/paper/5ymmswkdp0nka.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T13:21:15Z",
      "native_id": "W7162770254",
      "source": "openalex",
      "url": "https://doi.org/10.1073/pnas.2606521123"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:1902|Atmospheric chemistry and aerosols",
      "subfield": "atmospheric"
    }
  ],
  "title": "Marine upper-tropospheric rapid particle formation dominated by methanesulfonic acid",
  "title_text": "Marine upper-tropospheric rapid particle formation dominated by methanesulfonic acid",
  "type": "peer-reviewed",
  "updated_at": "2026-11-07T13:21:01Z",
  "url": "https://research.draconitic.com/paper/5ymmswkdp0nka",
  "venue": "Proceedings of the National Academy of Sciences",
  "versions": []
}