Isoprene as a probe of decadal changes in hydroxyl radical (OH)
Abstract
The hydroxyl radical (OH) is the primary daytime atmospheric oxidant and drives the chemistry that produces air pollutants including ozone and secondary organic aerosol. The OH concentration is a nonlinear function of the abundance of nitrogen oxides (NOx). Over the past several decades, NOx emissions in the U.S. have decreased due to effective regulations on NOx emission sources. These NOx controls have led to improvements in air quality and should have also led to changes in OH concentrations. Because we do not have direct observational constraints on multi-year trends in OH, we infer trends in the NOx dependence of OH through variability in atmospheric concentrations of isoprene, which is a reactive hydrocarbon emitted by plants. Here, we use over 20 years of isoprene observations from sites across the U.S. to describe long-term trends in OH.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A43M3294M
- Keywords:
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- 0317 Chemical kinetic and photochemical properties;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0368 Troposphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE