Abstract
The concentration of nitrogen oxides (NOx) plays a central role in controlling air quality. On a global scale, the primary sink of NOx is oxidation to form HNO3. Gas-phase HNO3 photolyses slowly with a lifetime in the troposphere of 10 days or more. However, several recent studies examining HONO chemistry have proposed that particle-phase HNO3 undergoes photolysis 10–300 times more rapidly than gas-phase HNO3. We present here constraints on the rate of particle-phase HNO3 photolysis based on observations of NOx and HNO3 collected over the Yellow Sea during the KORUS-AQ study in summer 2016. The fastest proposed photolysis rates are inconsistent with the observed NOx to HNO3 ratios. Negligible to moderate enhancements of the HNO3 photolysis rate in particles, 1–30 times faster than in the gas phase, are most consistent with the observations. Small or moderate enhancement of particle-phase HNO3 photolysis would not significantly affect the HNO3 budget but could help explain observations of HONO and NOx in highly aged air.
Department
Earth Systems Research Center
Publication Date
11-8-2018
Journal Title
Environmental Science & Technology
Publisher
ACS Publications
Digital Object Identifier (DOI)
https://dx.doi.org/10.1021/acs.est.8b03861
Document Type
Article
Recommended Citation
Romer, P. S., P. J. Wooldridge, J. D. Crounse, M. Kim, P. O. Wennberg, J. E. Dibb, E. Scheuer, D. R. Blake, S. Meinardi, A. L. Brosius, A. B. Thames, D. O. Miller, W. H. Brune, and R. C. Cohen (2018), Constraints on aerosol nitrate photolysis as a potential source of HONO and NOx, Environmental Science and Technology, Article ASAP (web publication), DOI: 10.1021/acs.est.8b03861.
Comments
This is an accepted manuscript of an article published by ACS Publications in 2018 in Environmental Science & Technology, available online: https://dx.doi.org/10.1021/acs.est.8b03861