Significant light induced ozone loss on biomass burning aerosol: Evidence from chemistry-transport modeling based on new laboratory studies

Recent laboratory studies indicated that a photo‐induced heterogeneous reaction of ozone on the surface of aerosol containing humic like substances (HULIS) has the potential to affect the ozone budget in biomass burning plumes. To evaluate atmospheric significance of such heterogeneous light induced ozone loss, this process has been taken into account in the simulation of the extreme air pollution episode in the Moscow region during the 2010 mega fire event in western Russia. Results of the numerical experiments performed with the CHIMERE chemistry transport model indicate that photo induced removal of ozone could lead to significant (reaching several tens of percent) episodic decrease of the ozone concentration. The simulations also show that while wildfires provide reactive surface for the considered reaction, they strongly inhibit the photo‐induced heterogeneous ozone loss by attenuating actinic fluxes through the “shielding” aerosol effect. The present results are calling for additional experimental and modelling studies. Key Points Photo induced ozone loss on biomass burning aerosol is a significant process Aerosol is a self‐inhibiting agent of the heterogeneous light induced ozone loss Uncertainties in reactivity of biomass burning aerosol call for new studies