The Potential Role of Criegee Intermediates in Nighttime Atmospheric Chemistry. A Modeling Study

Abstract

We evaluate the role of Criegee intermediates (CI) from ozonolysis of alkenes on nighttime chemistry in areas impacted by ozone and high emissions of biogenic volatile organic compounds, for example, the Southeast United States, using the Master Chemical Mechanism. Criegee reactions with NO2 may be an alternate source of NO3. Reactions of CI with NO3 have not been investigated but could influence NOx recycling. Evaluation of these reactions depends on recently measured rate constants for CI reactions with water vapor, NO2, and other trace gases. We vary the CI rate coefficients with NO2 and H2O and explore a range of initial conditions. We find that the CI production has the largest effects at low NO2 (<1 ppbv), high isoprene (10 ppbv) and low RH (<50%). At higher RH that is characteristic of the southeast U.S. and other high biogenic emitting regions, the effects are negligible using current literature values for CI rate constants with H2O. Under conditions for which CI reactions affect nighttime NO3 che...