Constraints on Aerosol Nitrate Photolysis as a Potential Source of HONO and NO x.

Academic Article


  • The concentration of nitrogen oxides (NO x) plays a central role in controlling air quality. On a global scale, the primary sink of NO x 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 NO x 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 NO x 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 NO x in highly aged air.
  • Authors

  • Romer, Paul S
  • Wooldridge, Paul J
  • Crounse, John D
  • Kim, Michelle J
  • Wennberg, Paul O
  • Dibb, Jack
  • Scheuer, Eric
  • Blake, Donald R
  • Meinardi, Simone
  • Brosius, Alexandra L
  • Thames, Alexander B
  • Miller, David O
  • Brune, William H
  • Hall, Samuel R
  • Ryerson, Thomas B
  • Cohen, Ronald C
  • Status

    Publication Date

  • December 4, 2018
  • Published In


  • Aerosols
  • Nitrates
  • Nitrogen Oxides
  • Nitrous Acid
  • Photolysis
  • Digital Object Identifier (doi)

    Pubmed Id

  • 30407797
  • Start Page

  • 13738
  • End Page

  • 13746
  • Volume

  • 52
  • Issue

  • 23