Journal article
pH Dependence of the OH Reactivity of Organic Acids in the Aqueous Phase
Environmental science & technology, Vol.54(19), pp.12484-12492
10/06/2020
DOI: 10.1021/acs.est.0c03331
PMID: 32936620
Abstract
Photochemical processing taking place in atmospheric aqueous phases serves as both a source and a sink of organic compounds. In aqueous environments, acid–base chemistry and, by extension, aqueous-phase pH, are an important yet often neglected factors to consider when investigating the kinetics of organic compounds. We have investigated the aqueous-phase OH-oxidation of pinic acid, cis-pinonic acid, limononic acid, and formic acid (FA) as a function of pH. We have also extended our studies to other organic acids (OAs) present in the water-soluble fraction of secondary organic aerosol (SOA) arising from the ozonolysis of α-pinene. Although all the OAs exhibited larger OH reactivities at pH 10, the pH dependence was dramatically different between FA, the smallest OA, and those that contained more than eight carbons. A kinetic box model was also employed to characterize our photoreactor and to provide confidence to our results. Our finding shows that the atmospheric lifetimes of small OAs (e.g., FA) are highly sensitive to cloud water pH. However, those of larger OAs and many other OAs in α-pinene SOA are affected to a much less extent. These results are of great importance for the simplification of cloud water chemistry models.
Details
- Title: Subtitle
- pH Dependence of the OH Reactivity of Organic Acids in the Aqueous Phase
- Creators
- Jéssica Vejdani Amorim - Department of ChemistryShuang Wu - Department of ChemistryKeifer Klimchuk - Department of ChemistryChester Lau - Department of ChemistryFlorence J Williams - Department of ChemistryYuanlong Huang - Division of Chemistry and Chemical EngineeringRan Zhao - Department of Chemistry
- Resource Type
- Journal article
- Publication Details
- Environmental science & technology, Vol.54(19), pp.12484-12492
- Publisher
- American Chemical Society
- DOI
- 10.1021/acs.est.0c03331
- PMID
- 32936620
- ISSN
- 0013-936X
- eISSN
- 1520-5851
- Grant note
- DOI: 10.13039/501100000190, name: University of Alberta; DOI: 10.13039/501100000038, name: Natural Sciences and Engineering Research Council of Canada
- Language
- English
- Date published
- 10/06/2020
- Academic Unit
- Iowa Neuroscience Institute; Chemistry
- Record Identifier
- 9984066337602771
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