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Published February 12, 2026 | Version Supplemental material
Journal Article Open

Detecting supramolecular organic nanoparticles during heat wave

Creators

  • 1. ROR icon Texas A&M University
  • 2. ROR icon Rockefeller University
  • 3. ROR icon California Institute of Technology
  • 4. ROR icon Stanford University

Abstract

New particle formation (NPF) represents a major source of tropospheric fine aerosols. A common viewpoint is that NPF hinges thermodynamically on the volatility of condensing species and is unfavorable at high temperatures. From an intensive field campaign, we observed frequent NPF events during a heat wave. Size-resolved chemical composition of nanoparticles down to 3 nanometers was first measured, unraveling a dominant presence of carboxylic acids. Our work uncovers a spontaneous mechanism to produce supramolecular nanoparticles through self-assembly of organic acids. This discovery explains not only the unexpected NPF at high temperatures but also its ubiquitous occurrence under diverse atmospheric conditions. As global warming leads to more frequent and intense heat waves, our findings open avenues for assessing the impacts of aerosols on cloud formation, public health, and climate.

Copyright and License

© 2026 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original US government works.

Acknowledgement

We thank M. Lester and S. Sorooshian for helpful discussions.

Funding

This work was supported by a grant from Texas A&M University (ASCEND/Targeted Proposal Team–TPT to R.Z.).

Contributions

R.Z. conceived of and supervised this project. Y.L. performed nanoparticle measurements. J.Z. and B.A.-O. performed gas measurements and theoretical calculations. L.Z. performed meteorological and air quality analyses. E.R.N. conducted atmospheric sounding measurements. R.Z and Y. L wrote the paper. All authors contributed to the research and approved the manuscript.

Data Availability

All data are available in the main text or the supplementary materials.

Supplemental Material

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Additional details

Identifiers

PMID
41678606

Funding

Texas A&M University

Dates

Submitted
2025-04-24
Accepted
2025-10-16

Caltech Custom Metadata

Caltech groups
Division of Chemistry and Chemical Engineering (CCE)
Publication Status
Published