Rachel O'Brien
University of Michigan, MI·Earth & Environmental Science·Early-career
Many chemicals in the air, from cleaning products to cooking fumes, do not stay the same once released. Over hours to weeks they react with ozone and other oxidants, which changes what they are, where they end up, and how harmful they may be.
- Fields
Earth & Environmental Science
Chemistry
Engineering
- Topics
atmospheric chemistry
indoor air quality
quaternary ammonium compounds
- Grants
- 2 known grants, through Aug 2028
What they work on
- Measure how fast quaternary ammonium compounds (QACs), common disinfectants, break down when exposed to OH radicals or ozone in airborne particles and indoor surface films.
- Test whether radical chain reactions speed up QAC oxidation, and whether thick, viscous films from other chemicals protect QACs from it.
- Identify QAC breakdown products with liquid and gas chromatography–mass spectrometry, then model where they travel indoors and how toxic they are using mass-balance calculations.
- Determine how water vapor changes the multi-generational aging of secondary organic aerosol, including whether molecules join into larger oligomers over days to weeks.
- Study long-term chemical aging of urban grime, including cooking organic aerosol and outdoor surface films, to estimate how much carbon stays in the condensed phase.
More about the research
These two projects measure how airborne particles and the films they leave on surfaces age chemically, indoors and outdoors.
Why it matters
Knowing which products form when disinfectants age indoors could lead to safer QAC structures and cleaning methods that still kill germs while reducing harm to people and the environment. Better estimates of how much organic carbon stays in aging aerosols could improve predictions of air quality, climate effects and health risks from air pollution.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Jesse Kroll
Massachusetts Institute of Technology, MA·Chemistry
Measure how ozone, formaldehyde and secondary organic aerosol form, and in what amounts, when isoprene, monoterpenes and aromatics are oxidized in chambers across the full range of atmospheric organic peroxy radical (RO2) conditions.
John Mak
Stony Brook University, NY·Earth & Environmental Science
Measure the specific volatile organic compounds over greater New York, including those from volatile chemical products, using instruments aboard the NSF C-130 aircraft.
Kerri Pratt
University of Michigan, MI·Chemistry
Measure bromine- and chlorine-containing gases, aerosols and cloud residual particles above and downwind of Arctic sea-ice leads, stretches of open water within ice cover, using the Wyoming King Air and Purdue ALAR research aircraft.
The school
University of Michigan: 124 labs on PI Pages, $2.1B a year on research, 963 research doctorates a year.
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