Ozone Formation Induced by the Impact of Reactive Bromine and Iodine Species on Photochemistry in a Polluted Marine Environment

Abstract

Reactive iodine and bromine species (RIS and RBS, respectively) are known for altering atmospheric chemistry and causing sharp tropospheric ozone (O) depletion in polar regions and significant O reduction in the marine boundary layer (MBL). Here we use measurement-based modeling to show that, unexpectedly, both RIS and RBS can lead to enhanced O formation in a polluted marine environment under volatile organic compound (VOC)-limited conditions associated with high nitrogen oxide (NO = [NO] + [NO]) concentrations. Under these conditions, the daily average O mixing ratio increased to ∼44 and ∼28% for BrO and IO mixing ratios of up to ∼6.8 and 4.7 ppt, respectively. The increase in the level of O was partially induced by enhanced ClNO formation for higher Br and I emission flux. The increase in the level of O was associated with an increased mixing ratio of hydroperoxyl radical to hydroxyl radical ([HO]/[OH]) and increased [NO]/[NO] with higher levels of RBS and/or RIS. NO-rich conditions are typical of the polluted MBL, near coastlines and ship plumes. Considering that O is toxic to humans, plants, and animals and is a greenhouse gas, our findings call for adequate updating of local and regional air-quality models with the effects of activities of RBS and RIS on O mixing ratios in the polluted MBL.

Enhanced Chlorine and Bromine Atom Activation by Hydrolysis of Halogen Nitrates from Marine Aerosols at Polluted Coastal Areas

“…Nevertheless, possible important effects of INO 3 hydrolysis under high NO x polluted conditions with NO 2 concentrations above 1 ppb have not yet been investigated. Shechner and Tas clearly demonstrated that XNO 3 hydrolysis has a crucial impact on the atmospheric oxidation capacity. Still, their work focused on ozone formation under VOC-limited high NO x conditions, but neglected the influence on Cl activation.…”

“…Still, their work focused on ozone formation under VOC-limited high NO x conditions, but neglected the influence on Cl activation. Shechner and Tas highlighted that improved studies on XNO 3 and especially INO 3 hydrolysis and its effects on atmospheric chemistry are necessary.…”

CAPRAM reduction towards an operational multiphase halogen and dimethyl sulfide chemistry treatment in the chemistry transport model COSMO-MUSCAT(5.04e)

“…The chemistry of reactive halogen compounds as well as of DMS is very sensitive to anthropogenic pollution. The advection of NO x and ozone has strong effects on the activation of reactive halogen compounds (Hoffmann et al, 2019b;Shechner and Tas, 2017;Mahajan et al, 2009b, a;McFiggans et al, 2002) and on DMS oxidation (Breider et al, 2010;Barnes et al, 2006;Chen et al, 2018). Moreover, reactive halogen compounds can significantly influence the depletion of NO x , ozone, SO 2 , volatile organic compounds (VOCs), and oxidized volatile organic compounds (OVOCs) (von Glasow et al, 2002b, a;Sherwen et al, 2017Sherwen et al, , 2016Schmidt et al, 2016).…”

CAPRAM reduction towards an operational multiphase halogen and DMS chemistry treatment in the chemistry transport model COSMO-MUSCAT(5.04e)

“…The chemistry of reactive halogen compounds as well as of DMS is very sensitive to anthropogenic pollution. The advection of NOx and ozone has strong effects on the activation of reactive halogen compounds (Hoffmann et al, 2019b;Shechner and Tas, 2017;Mahajan et al, 2009b;Mahajan et al, 2009a;McFiggans et al, 2002) and on DMS oxidation (Breider et al, 2010; Barnes et al, 2006;Chen et al, 2018). Moreover, reactive halogen compounds can significantly influence the depletion of NOx, ozone, SO2, volatile organic compounds (VOCs), and oxidised volatile organic compounds (OVOCs) (von Glasow et al, 2002b, a;Sherwen et al, 2017;Schmidt et al, 2016;.…”