Scratching the Surface of Individual Aerosol Particle Properties

Ault, Andrew P.; Waters, Cara M.

doi:10.1021/acscentsci.3c01362

Cited by 2 publications

(1 citation statement)

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“…More single-particle analysis is needed as the climate and health impacts of aerosols are largely driven by single particle composition and physical properties (size, optical properties, hygroscopicity, etc. ). − …”

Section: Introductionmentioning

confidence: 99%

Atmospheric Aerosol Sulfur Distribution and Speciation in Mexico City: Sulfate, Organosulfates, and Isoprene-Derived Secondary Organic Aerosol from Low NO Pathways

Cooke,

Waters,

Asare

et al. 2024

ACS EST Air

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Poor air quality is a persistent challenge in Mexico City, and addressing this issue requires an understanding of the chemical composition of PM2.5 (particulate matter less than 2.5 μm in diameter). Sulfate and secondary organic aerosol (SOA) are two of the largest contributors to PM2.5 in Mexico City, but uncertainties exist regarding their sources, distribution across individual particles, and ability to form organosulfates. Herein, we show using electron dispersive x-ray spectroscopy that only 41 ± 1% and 25 ± 1% of particles (aerodynamic diameter, 0.32–0.56 μm) by number at two sites in Mexico City, respectively, contain sulfur. Vibrational spectroscopy (Optical-Photothermal Infrared + Raman Microspectroscopy) shows that these sulfur-containing particles consist of inorganic sulfate (SO4 2–) and organosulfates (ROSO3 –). In addition, we unexpectedly measured abundant isoprene-derived SOA from low nitric oxide reaction pathways, specifically organosulfates (methyltetrol sulfates = avg. 50 ng/m3, max. 150 ng/m3) and polyols (methyltetrols = avg. 70 ng/m3, max. 190 ng/m3) using liquid chromatography with high-resolution mass spectrometry. Differences in SO2 and NO x concentrations between sites likely contribute to these spatial differences in sulfate, organosulfate, and SOA formation. These findings improve understanding of sulfur distribution and sources of SOA in Mexico City, which can inform efforts to improve air quality.

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Section: Introductionmentioning

confidence: 99%