Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要:
Bromine chemistry, particularly in the tropics, has been suggested to play an important role in tropospheric ozone loss although a lack of measurements of active bromine species impedes a quantitative understanding of its impacts. Recent modelling and measurements of bromine monoxide (BrO) by Wang et�al. (2015) have shown current models under predict BrO concentrations over the Pacific Ocean and allude to a missing source of BrO. Here, we present the first simultaneous aircraft measurements of atmospheric bromine monoxide, BrO (a radical that along with atomic Br catalytically destroys ozone) and the inorganic Br precursor compounds HOBr, BrCl and Br2over the Western Pacific Ocean from 0.5 to 7�km. The presence of 0.17–1.64 pptv BrO and 3.6–8 pptv total inorganic Br from these four species throughout the troposphere causes 10–20% of total ozone loss, and confirms the importance of bromine chemistry in the tropical troposphere; contributing to a 6�ppb decrease in ozone levels due to halogen chemistry. Observations are compared with a global chemical transport model and find that the observed high levels of BrO, BrCl and HOBr can be reconciled by active multiphase oxidation of halide (Br−and Cl−) by HOBr and ozone in cloud droplets and aerosols. Measurements indicate that 99% of the instantaneous free Br in the troposphere up to 8�km originates from inorganic halogen photolysis rather than from photolysis of organobromine species. � 2017
The Centre for Atmospheric Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Simon Building, Brunswick Street, Manchester, United Kingdom; School of Chemistry, University of Bristol, Cantock's Close, Bristol, United Kingdom; National Centre for Atmospheric Science (NCAS), Department of Chemistry, University of York, York, United Kingdom; Harvard University, School of Engineering and Applied Sciences, 29 Oxford St, Cambridge, United States; Department of Chemistry, University of Copenhagen, Copenhagen, Denmark; Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; Facility for Airborne Atmospheric Measurements (FAAM), Cranfield University, Building 125, Cranfield, Bedford, United Kingdom
Recommended Citation:
Le Breton M,, Bannan T,J,et al. Enhanced ozone loss by active inorganic bromine chemistry in the tropical troposphere[J]. Atmospheric Environment,2017-01-01,155