Enrichment of Phosphates, Lead, and Mixed Soil-Organic Particles in INPs at the Southern Great Plains Site

Gavin C. Cornwell*, Isabelle Steinke, Nurun Nahar Lata, Alla Zelenyuk, Gourihar Kulkarni, Mikhail Pekour, Russell Perkins, Ezra J.T. Levin, Swarup China, Paul J. DeMott, Susannah M. Burrows

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Ice nucleating particles (INPs) are rare particles that initiate primary ice formation, a critical step required for subsequent important cloud microphysical processes that ultimately govern cloud phase and cloud radiative properties. Laboratory studies have found that organic-rich dusts, such as those found in soils, are more efficient INPs compared to mineral dust. However, the atmospheric relevance of these organic-rich dusts are not well understood, particularly in regions with significant agricultural activity. The Agricultural Ice nuclei at the Southern Great Plains field campaign (AGINSGP) was conducted in rural Oklahoma to investigate how soil dusts contribute to INP populations in the Great Plains. We present chemical characterization of ambient and ice crystal residual particles from a single day of sampling, using single particle mass spectrometry (SPMS) and scanning microscopy. Ambient particles were primarily carbonaceous or secondary aerosol, while the fraction of dust particles was higher in the residual particles. We also observed an unusual particle type consisting of a carbonaceous core mixed with dust fragments on the surface, which was found in higher proportion in residuals. Dust particles measured during residual sampling contained greater proportions of phosphate (63PO2 and 79PO3) and lead (206Pb+). Strong sulfate signals were not seen in the residual dust particles measured by the SPMS, while nitrate was slightly depleted relative to ambient dust. This study shows that organic-rich soils may be important contributors to the ambient INP population in agricultural regions.
Original languageEnglish
Article numbere2024JD040826
Number of pages17
JournalJournal of Geophysical Research: Atmospheres
Volume129
Issue number13
DOIs
Publication statusPublished - 2024
Externally publishedYes

Keywords

  • ice nucleating particles
  • lead
  • phosphate
  • residuals
  • soil dust

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