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. 2015 May 27;115(10):4035-62.
doi: 10.1021/cr5006638. Epub 2015 Mar 12.

Tropospheric halogen chemistry: sources, cycling, and impacts

William R Simpson  1 , Steven S Brown  2 , Alfonso Saiz-Lopez  3 , Joel A Thornton  4 , Roland von Glasow  5
Affiliations

Tropospheric halogen chemistry: sources, cycling, and impacts

William R Simpson et al. Chem Rev. .
No abstract available

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Figures

Figure 1
Figure 1
Simplified reaction diagram for halogen atoms, represented as “X” in this diagram, key chemical reaction pathways. Note that many species on this diagram are radicals, but for simplicity, only organic radicals and organic peroxy radicals, denoted by R• and RO2•, are explicitly shown with an unpaired electron.
Figure 2
Figure 2
Primary sources of reactive halogen species or their precursor reservoir species overlain on a MODIS image of Earth. Background image produced by the MODIS Land Group, NASA Goddard Space Flight Center, Visible Earth Project, NASA.
Figure 3
Figure 3
Br2 production during a snow chamber experiments on 27 March 2012. Tundra snow is exposed to ambient radiation and varying ozone levels, and produced Br2 is monitored. Reprinted with permission from Pratt and co-workers (2013). Copyright 2013 Nature Publishing Group.
Figure 4
Figure 4
Evolution of dihalogen gases from laboratory experiments simulating polar halogen activation by irradiating salt-doped ice particles with or without coexposure to ozone gas. Panel a shows dihalogens (Br2 in red, Cl2 in black, and BrCl in green. Panel b shows ozone, and yellow areas indicate times when the sample was irradiated. The dotted shading visible on top of the yellow indicates when the ozone generator was switched on (dotted = ozone on, no dots = ozone off). Reprinted with permission from Wren and co-workers (2013). Copyright Wren and co-workers 2013. CC Attribution 3.0 License.
Figure 5
Figure 5
Simulated column amounts of BrO in the atmosphere versus time from the 1-D model of Toyota and co-workers (2014). The panels show different assumptions for turbulence in the atmospheric boundary layer based upon windspeed, U2, and various values of the Brunt–Väisälä frequency, N. Note that the BrO column scale on each panel is different, and the higher windspeeds show much higher VCDs. Reprinted with permission from Toyota and co-workers (2014). Copyright Toyota and co-workers 2014. CC Attribution 3.0 License.
Figure 6
Figure 6
Marine boundary layer iodine monoxide (IO) observations from ship cruise and coastal station observations in pmol/mol. Reprinted with permission from Prados-Roman and co-workers (2015). Copyright Prados-Roman and co-workers 2015. CC Attribution 3.0 License.
Figure 7
Figure 7
Nightime observations of NOx polluted air containing N2O5 and produced reactive halogen precursor, nitryl chloride, ClNO2, measured at the Scripps Institution of Oceanography Pier. Reprinted with permission from Kim and co-workers (2014). Copyright 2014 National Academy of Sciences.
Figure 8
Figure 8
Conversion efficiency for production of ClNO2 from N2O5 from laboratory measurements along with models. Panel b shows ranges of particulate chloride composition from the TexAQS-GoMACCS 2006 field campaign. Reprinted with permission from Roberts and co-workers (2009). Copyright 2009 American Geophysical Union.
Figure 9
Figure 9
Mean of nightly 1 h maximum ClNO2 in January without the heterogeneous ClNO2 production (pptv = pmol/mol), (b) mean of nightly 1 h maximum ClNO2 in June without the heterogeneous ClNO2 production (pptv = pmol/mol), (c) mean of nightly 1 h maximum ClNO2 in January with the heterogeneous ClNO2 production (ppbv = nmol/mol), and (d) mean of nightly 1 h maximum ClNO2 in June with the heterogeneous ClNO2 production (ppbv = nmol/mol). Reprinted with permission from Sarwar and co-workers (2014). Copyright 2014 American Geophysical Union.
Figure 10
Figure 10
Seasonal variation of mean annual tropospheric BrO simulated by GEOS-Chem along with GOME-2 observations and p-TOMCAT model simulations. The effect of removing the heterogeneous reaction of HBr + HOBr is demonstrated in the GEOS-Chem simulations. Reprinted with permission from Parrella and co-workers (2014). Copyright Parrella and co-workers 2014. CC Attribution 3.0 License.
Figure 11
Figure 11
Modeled anthropogenic influence on oceanic iodine source as a percentage change from preindustrial times to current conditions. Reprinted with permission from Prados-Roman and co-workers. Copyright Prados-Roman and co-workers 2015. CC Attribution 3.0 License.
See this image and copyright information in PMC

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