ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-6723-2012 Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury Parrella J. P. 1 Jacob D. J. 1 Liang Q. 2 3 Zhang Y. 4 Mickley L. J. 1 Miller B. 1 Evans M. J. 5 6 Yang X. 7 8 Pyle J. A. 7 8 Theys N. 9 Van Roozendael M. 9 School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA Universities Space Research Association GESTAR, Columbia, MD, USA NASA Goddard Space Flight Center, Greenbelt, MD, USA Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA Department of Chemistry, University of York, York, UK National Centre for Atmospheric Sciences (NCAS), York, UK National Centre for Atmospheric Sciences (NCAS), Cambridge, UK Centre for Atmospheric Sciences, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK Belgian Institute for Space Aeronomy (IASB-BIRA), Brussels, Belgium 01 08 2012 12 15 6723 6740 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/12/6723/2012/acp-12-6723-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/6723/2012/acp-12-6723-2012.pdf

We present a new model for the global tropospheric chemistry of inorganic bromine (Br<sub>y</sub>) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Br<sub>y</sub> include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1–8 nmol mol<sup>−1</sup> (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

 References Abbatt, J. P. D.: Heterogeneous reaction of HOBr with HBr and HCl on ice surfaces at 228 K, Geophys. Res. Lett., 21, 665–668, http://dx.doi.org/10.1029/94gl00775doi:10.1029/94gl00775, 1994. Abbatt, J. P. D.: Interactions of HBr, HCl, and HOBr with supercooled sulfuric acid solutions of stratospheric composition, J. Geophys. Res., 100, 14009–14017, http://dx.doi.org/10.1029/95jd01367doi:10.1029/95jd01367, 1995. Abbatt, J. P. D. and Waschewsky, G. C. G.: Heterogeneous Interactions of HOBr, HNO<sub>3</sub>, O<sub>3</sub>, and NO<sub>2</sub> with Deliquescent NaCl Aerosols at Room Temperature, J. Phys. Chem. A, 102, 3719–3725, http://dx.doi.org/10.1021/jp980932ddoi:10.1021/jp980932d, 1998. Alexander, B., Park, R. J., Jacob, D. J., Li, Q. B., Yantosca, R. M., Savarino, J., Lee, C. C. W., and Thiemens, M. H.: Sulfate formation in sea-salt aerosols: Constraints from oxygen isotopes, J. Geophys. Res., 110, D10307, http://dx.doi.org/10.1029/2004jd005659doi:10.1029/2004jd005659, 2005. Arnaud, P.: Cours de chimie organique, 3 Edn., Gauthier-Villars, Paris, 1966. Atkinson, R., Baulch, D. L., Cox, R. A., Hampson, R. F., Rossi, M. J., and Troe, J.: Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry: Supplement VIII, J. Phys. Chem. Ref. Data, 29, 167–266, 2000a. Atkinson, R., Baulch, D. L., Cox, R. A., Hampson, R. F., Rossi, M. J., and Troe, J.: Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry. Supplement IX, Heterogeneous Chemistry, non-reactive uptake, http://www.iupac-kinetic.ch.cam.ac.uk/, 2000b. Balkanski, Y. J., Jacob, D. J., Gardner, G. M., Graustein, W. C., and Turekian, K. K.: Transport and Residence Times of Tropospheric Aerosols Inferred from a Global Three-Dimensional Simulation of $^210$Pb, J. Geophys. Res., 98, 20573–20586, http://dx.doi.org/10.1029/93jd02456doi:10.1029/93jd02456, 1993. Beckwith, R. C., Wang, T. X., and Margerum, D. W.: Equilibrium and Kinetics of Bromine Hydrolysis, Inorg. Chem., 35, 995–1000, http://dx.doi.org/10.1021/ic950909wdoi:10.1021/ic950909w, 1996. Bergan, T., Gallardo, L., and Rodhe, H.: Mercury in the global troposphere: a three-dimensional model study, Atmos. Environ., 33, 1575–1585, 1999. Bey, I., Jacob, D. J., Yantosca, R. M., Logan, J. A., Field, B. D., Fiore, A. M., Li, Q., Liu, H. Y., Mickley, L. J., and Schultz, M. G.: Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res., 106, 23073–23095, 2001. Butler, J. H., King, D. B., Lobert, J. M., Montzka, S. A., Yvon-Lewis, S. A., Hall, B. D., Warwick, N. J., Mondeel, D. J., Aydin, M., and Elkins, J. W.: Oceanic distributions and emissions of short-lived halocarbons, Global Biogeochem. Cy., 21, GB1023, http://dx.doi.org/10.1029/2006gb002732doi:10.1029/2006gb002732, 2007. Calvert, J. G. and Lindberg, S. E.: Mechanisms of mercury removal by O<sub>3</sub> and OH in the atmosphere, Atmos. Environ., 39, 3355–3367, 2005. Carpenter, L. J., Sturges, W. T., Penkett, S. A., Liss, P. S., Alicke, B., Hebestreit, K., and Platt, U.: Short-lived alkyl iodides and bromides at Mace Head, Ireland: Links to biogenic sources and halogen oxide production, J. Geophys. Res., 104, 1679–1689, 1999. Chaix, L., Allanic, A., and Rossi, M. J.: Heterogeneous Chemistry of HOBr on Different Types of Ice and on Ice Doped with HCl, HBr, and HNO<sub>3</sub> at 175 K < T < 215 K, J. Phys. Chem. A, 104, 7268–7277, http://dx.doi.org/10.1021/jp001018zdoi:10.1021/jp001018z, 2000. Clerbaux, C., Cunnold, D. M. (Coordinating Lead Authors), Anderson, J., Engel, A., Fraser, P. J., Mahieu, E., Manning, A., Miller, J., Montzka, S. A., Nassar, R., Prinn, R., Reimann, S., Rinsland, C. P., Simmonds, P., Verdonik, D., Weiss, R., Wuebbles, D., and Yokouchi, Y.: Long-lived compounds, Chapter 1 in Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project-Report No. 50, World Meteorological Organization, Geneva, Switzerland, 2007. Crutzen, P. J. and Schmailzl, U.: Chemical budgets of the stratosphere, Planet. Space Sci., 31, 1009–1032, 1983. Dean, J. A.: Lange's Handbook of Chemistry, McGraw-Hill, Inc., 1992. Dentener, F., Keating, T., and Akimoto, H. (Eds.): Part A in Hemispheric Transport of Air Pollution, Ozone and Particulate Matter, United Nations Economic Commission for Europe, New York, 2010. Derwent, R. G., Simmonds, P. G., Manning, A. J., and Spain, T. G.: Trends over a 20-year period from 1987 to 2007 in surface ozone at the atmospheric research station, Mace Head, Ireland, Atmos. Environ., 41, 9091–9098, 2007. Donohoue, D. L., Bauer, D., Cossairt, B., and Hynes, A. J.: Temperature and Pressure Dependent Rate Coefficients for the Reaction of Hg with Br and the Reaction of Br with Br: A Pulsed Laser Photolysis-Pulsed Laser Induced Fluorescence Study, J. Phys. Chem. A, 110, 6623–6632, http://dx.doi.org/10.1021/jp054688jdoi:10.1021/jp054688j, 2006. Fickert, S., Adams, J. W., and Crowley, J. N.: Activation of Br<sub>2</sub> and BrCl via uptake of HOBr onto aqueous salt solutions, J. Geophys. Res., 104, 23719–23727, http://dx.doi.org/10.1029/1999jd900359doi:10.1029/1999jd900359, 1999. Fischer, E. V., Jacob, D. J., Millet, D. B., Yantosca, R. M., and Mao, J.: The role of the ocean in the global atmospheric budget of acetone, Geophys. Res. Lett., 39, L01807, http://dx.doi.org/10.1029/2011gl050086doi:10.1029/2011gl050086, 2012. Fisher, J. A., Jacob, D. J., Purdy, M. T., Kopacz, M., Le Sager, P., Carouge, C., Holmes, C. D., Yantosca, R. M., Batchelor, R. L., Strong, K., Diskin, G. S., Fuelberg, H. E., Holloway, J. S., Hyer, E. J., McMillan, W. W., Warner, J., Streets, D. G., Zhang, Q., Wang, Y., and Wu, S.: Source attribution and interannual variability of Arctic pollution in spring constrained by aircraft (ARCTAS, ARCPAC) and satellite (AIRS) observations of carbon monoxide, Atmos. Chem. Phys., 10, 977–996, http://dx.doi.org/10.5194/acp-10-977-2010doi:10.5194/acp-10-977-2010, 2010. Fitzenberger, R., Bösch, H., Camy-Peyret, C., Chipperfield, M. P., Harder, H., Platt, U., Sinnhuber, B., M, Wagner, T., and Pfeilsticker, K.: First profile measurements of tropospheric BrO, Geophys. Res. Lett., 27, 2921–2924, http://dx.doi.org/10.1029/2000gl011531doi:10.1029/2000gl011531, 2000. Frenzel, A., Scheer, V., Sikorski, R., George, C., Behnke, W., and Zetzsch, C.: Heterogeneous Interconversion Reactions of BrNO<sub>2</sub>, ClNO<sub>2</sub>, Br<sub>2</sub>, and Cl<sub>2</sub>, J. Phys. Chem. A, 102, 1329–1337, http://dx.doi.org/10.1021/jp973044bdoi:10.1021/jp973044b, 1998. Frieß, U., Chipperfield, M. P., Harder, H., Otten, C., Platt, U., Pyle, J., Wagner, T., and Pfeilsticker, K.: Intercomparison of measured and modelled BrO slant column amounts for the Arctic winter and spring 1994/95, Geophys. Res. Lett., 26, 1861–1864, http://dx.doi.org/10.1029/1999gl900345doi:10.1029/1999gl900345, 1999. Fu, T.-M., Jacob, D. J., Wittrock, F., Burrows, J. P., Vrekoussis, M., and Henze, D. K.: Global budgets of atmospheric glyoxal and methylglyoxal, and implications for formation of secondary organic aerosols, J. Geophys. Res., 113, D15303, http://dx.doi.org/10.1029/2007jd009505doi:10.1029/2007jd009505, 2008. Goodsite, M. E., Plane, J. M. C., and Skov, H.: A Theoretical Study of the Oxidation of Hg$^0$ to HgBr<sub>2</sub> in the Troposphere, Environ. Sci. Technol., 38, 1772–1776, http://dx.doi.org/10.1021/es034680sdoi:10.1021/es034680s, 2004. Haag, W. R. and Hoigne, J.: Ozonation of bromide-containing waters: kinetics of formation of hypobromous acid and bromate, Environ. Sci. Technol., 17, 261–267, http://dx.doi.org/10.1021/es00111a004doi:10.1021/es00111a004, 1983. Harder, H., Camy, Peyret, C., Ferlemann, F., Fitzenberger, R., Hawat, T., Osterkamp, H., Schneider, M., Perner, D., Platt, U., Vradelis, P., and Pfeilsticker, K.: Stratospheric BrO profiles measured at different latitudes and seasons: Atmospheric observations, Geophys. Res. Lett., 25, 3843–3846, http://dx.doi.org/10.1029/1998gl900026doi:10.1029/1998gl900026, 1998. Hendrick, F., Van Roozendael, M., Chipperfield, M. P., Dorf, M., Goutail, F., Yang, X., Fayt, C., Hermans, C., Pfeilsticker, K., Pommereau, J.-P., Pyle, J. A., Theys, N., and De Mazière, M.: Retrieval of stratospheric and tropospheric BrO profiles and columns using ground-based zenith-sky DOAS observations at Harestua, 60° N, Atmos. Chem. Phys., 7, 4869–4885, http://dx.doi.org/10.5194/acp-7-4869-2007doi:10.5194/acp-7-4869-2007, 2007. Holmes, C. D., Jacob, D. J., and Yang, X.: Global lifetime of elemental mercury against oxidation by atomic bromine in the free troposphere, Geophys. Res. Lett., 33, L20808, http://dx.doi.org/10.1029/2006gl027176doi:10.1029/2006gl027176, 2006. Holmes, C. D., Jacob, D. J., Mason, R. P., and Jaffe, D. A.: Sources and deposition of reactive gaseous mercury in the marine atmosphere, Atmos. Environ., 43, 2278–2285, 2009. Holmes, C. D., Jacob, D. J., Corbitt, E. S., Mao, J., Yang, X., Talbot, R., and Slemr, F.: Global atmospheric model for mercury including oxidation by bromine atoms, Atmos. Chem. Phys., 10, 12037–12057, http://dx.doi.org/10.5194/acp-10-12037-2010doi:10.5194/acp-10-12037-2010, 2010. Horowitz, L. W.: Past, present, and future concentrations of tropospheric ozone and aerosols: Methodology, ozone evaluation, and sensitivity to aerosol wet removal, J. Geophys. Res., 111, D22211, http://dx.doi.org/10.1029/2005JD006937doi:10.1029/2005JD006937, 2006. Hossaini, R., Chipperfield, M. P., Monge-Sanz, B. M., Richards, N. A. D., Atlas, E., and Blake, D. R.: Bromoform and dibromomethane in the tropics: a 3-D model study of chemistry and transport, Atmos. Chem. Phys., 10, 719–735, http://dx.doi.org/10.5194/acp-10-719-2010doi:10.5194/acp-10-719-2010, 2010. Hynes, A. J., Donohoue, D. L., Goodsite, M. E., Hedgecock, I. M., Pirrone, N., and Mason, R.: Our current understanding of major chemical and physical processes affecting mercury dynamics in the atmosphere and at the air-water/terrestrial interfaces, in: Mercury Fate and Transport in the Global Atmosphere, edited by: Pirrone, N. and Mason, R. P., Springer, chap. 14, 427–457, 2009. Jacob, D. J.: Heterogeneous chemistry and tropospheric ozone, Atmos. Environ., 34, 2131–2159, 2000. Jacobson, M. Z. and Turco, R. P.: SMVGEAR: A sparse-matrix, vectorized gear code for atmospheric models, Atmos. Environ., 28, 273–284, 1994. Kerkweg, A., Jöckel, P., Warwick, N., Gebhardt, S., Brenninkmeijer, C. A. M., and Lelieveld, J.: Consistent simulation of bromine chemistry from the marine boundary layer to the stratosphere – Part 2: Bromocarbons, Atmos. Chem. Phys., 8, 5919–5939, http://dx.doi.org/10.5194/acp-8-5919-2008doi:10.5194/acp-8-5919-2008, 2008. Kiehl, J. T., Schneider, T. L., Portmann, R. W., and Solomon, S.: Climate forcing due to tropospheric and stratospheric ozone, J. Geophys. Res., 104, 31239–31254, http://dx.doi.org/10.1029/1999jd900991doi:10.1029/1999jd900991, 1999. King, K. D., Golden, D. M., and Benson, S. W.: Kinetics of the gas-phase thermal bromination of acetone. Heat of formation and stabilization energy of the acetonyl radical, J. Am. Chem. Soc., 92, 5541–5546, http://dx.doi.org/10.1021/ja00722a001doi:10.1021/ja00722a001, 1970. Lamarque, J.-F., Hess, P., Emmons, L., Buja, L., Washington, W., and Granier, C.: Tropospheric ozone evolution between 1890 and 1990, J. Geophys. Res., 110, D08304, http://dx.doi.org/10.1029/2004JD005537doi:10.1029/2004JD005537, 2005. Lary, D. J.: Halogens and the chemistry of the free troposphere, Atmos. Chem. Phys., 5, 227–237, http://dx.doi.org/10.5194/acp-5-227-2005doi:10.5194/acp-5-227-2005, 2005. Law, K. S., Sturges, W. T. (Coordinating Lead Authors), Blake, D. R., Blake, N. J., Burkholder, J. B., Butler, J. H., Cox, R. A., Haynes, P. H., Ko, M. K. W., Kreher, K., Mari, C., Pfeilsticker, K., Plane, J. M. C., Salawitch, R. J., Schiller, C., Sinnhuber, B.-M., von Glasow, R., Warwick, N. J., Wuebbles, D. J., and Yvon-Lewis, S. A.: Halogenated Very Short-Lived Substances, Chapter 2 in Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project-Report No. 50, World Meteorological Organization, Geneva, Switzerland, 2007. Lawrence, M. G. and Crutzen, P. J.: The impact of cloud particle gravitational settling on soluble trace gas distributions, Tellus B, 50, 263–289, 1998. Lelieveld, J., van Aardenne, J., Fischer, H., de Reus, M., Williams, J., and Winkler, P.: Increasing Ozone over the Atlantic Ocean, Science, 304, 1483–1487, http://dx.doi.org/10.1126/science.1096777doi:10.1126/science.1096777, 2004. Lewis, E. R. and Schwartz, S. E.: Sea Salt Aerosol Production: Mechanisms, Methods, Measurements and Models – A Critical Review, Geophysical Monograph 152, AGU, Washington, DC, 2004. Liang, Q., Stolarski, R. S., Kawa, S. R., Nielsen, J. E., Douglass, A. R., Rodriguez, J. M., Blake, D. R., Atlas, E. L., and Ott, L. E.: Finding the missing stratospheric Bry: a global modeling study of CHBr<sub>3</sub> and CH<sub>2</sub>Br<sub>2</sub>, Atmos. Chem. Phys., 10, 2269–2286, http://dx.doi.org/10.5194/acp-10-2269-2010doi:10.5194/acp-10-2269-2010, 2010. Lin, J.-T., McElroy, M. B., and Boersma, K. F.: Constraint of anthropogenic NO$_\mathrmx$ emissions in China from different sectors: a new methodology using multiple satellite retrievals, Atmos. Chem. Phys., 10, 63–78, http://dx.doi.org/10.5194/acp-10-63-2010doi:10.5194/acp-10-63-2010, 2010. Lindberg, S., Bullock, R., Ebinghaus, R., Engstrom, D., Feng, X., Fitzgerald, W., Pirrone, N., Prestbo, E., and Seigneur, C.: A Synthesis of Progress and Uncertainties in Attributing the Sources of Mercury in Deposition, AMBIO, 36, 19–33, 2007. Liu, H., Jacob, D. J., Bey, I., and Yantosca, R. M.: Constraints from $^210$Pb and $^7$Be on wet deposition and transport in a global three-dimensional chemical tracer model driven by assimilated meteorological fields, J. Geophys. Res., 106, 12109–12128, http://dx.doi.org/10.1029/2000jd900839doi:10.1029/2000jd900839, 2001. Logan, J. A., Staehelin, J., Megretskaia, I. A., Cammas, J.-P., Thouret, V., Claude, H., De Backer, H., Steinbacher, M., Scheel, H. E., Stubi, R., Frohlich, M., and Derwent, R. G.: Changes in ozone over Europe since 1990: analysis of ozone measurements from sondes regular aircraft (MOZAIC) and alpine surface sites, J. Geophys. Res., 117, D09301, http://dx.doi.org/10.1029/2011JD016952doi:10.1029/2011JD016952, 2012. Mao, J., Jacob, D. J., Evans, M. J., Olson, J. R., Ren, X., Brune, W. H., Clair, J. M. St., Crounse, J. D., Spencer, K. M., Beaver, M. R., Wennberg, P. O., Cubison, M. J., Jimenez, J. L., Fried, A., Weibring, P., Walega, J. G., Hall, S. R., Weinheimer, A. J., Cohen, R. C., Chen, G., Crawford, J. H., McNaughton, C., Clarke, A. D., Jaeglé, L., Fisher, J. A., Yantosca, R. M., Le Sager, P., and Carouge, C.: Chemistry of hydrogen oxide radicals (HO$_\mathrmx$) in the Arctic troposphere in spring, Atmos. Chem. Phys., 10, 5823–5838, http://dx.doi.org/10.5194/acp-10-5823-2010doi:10.5194/acp-10-5823-2010, 2010. Mao, J., Fan, S.-M., and Jacob, D. J.: Radical loss in the atmosphere from Cu-Fe redox coupling in aerosol, Nature, submitted, 2012. Marenco, A., Gouget, H., Nédélec, P., Pagés, J.-P., and Karcher, F.: Evidence of a long-term increase in tropospheric ozone from Pic du Midi data series: Consequences: Positive radiative forcing, J. Geophys. Res., 99, 16617–16632, 1994. Martin, R. V., Jacob, D. J., Logan, J. A., Bey, I., Yantosca, R. M., Staudt, A. C., Li, Q., Fiore, A. M., Duncan, B. N., Liu, H., Ginoux, P., and Thouret, V.: Interpretation of TOMS observations of tropical tropospheric ozone with a global model and in situ observations, J. Geophys. Res., 107, 4351, http://dx.doi.org/10.1029/2001jd001480doi:10.1029/2001jd001480, 2002. McGrath, M. P. and Rowland, F. S.: Ideal Gas Thermodynamic Properties of HOBr, J. Phys. Chem., 98, 4773–4775, http://dx.doi.org/10.1021/j100069a001doi:10.1021/j100069a001, 1994. McLinden, C. A., Olsen, S. C., Hannegan, B., Wild, O., Prather, M. J., and Sundet, J.: Stratospheric ozone in 3-D models: A simple chemistry and the cross-tropopause flux, J. Geophys. Res., 105, 14653–14665, 2000. Mickley, L. J., Murti, P. P., Jacob, D. J., Logan, J. A., Koch, D. M., and Rind, D.: Radiative forcing from tropospheric ozone calculated with a unified chemistry-climate model, J. Geophys. Res., 104, 30153–30172, http://dx.doi.org/10.1029/1999jd900439doi:10.1029/1999jd900439, 1999. Mickley, L. J., Jacob, D. J., and Rind, D.: Uncertainty in preindustrial abundance of tropospheric ozone: Implications for radiative forcing calculations, J. Geophys. Res., 106, 3389–3399, http://dx.doi.org/10.1029/2000jd900594doi:10.1029/2000jd900594, 2001. Mochida, M., Akimoto, H., van den Bergh, H., and Rossi, M. J.: Heterogeneous Kinetics of the Uptake of HOBr on Solid Alkali Metal Halides at Ambient Temperature, J. Phys. Chem. A, 102, 4819–4828, http://dx.doi.org/10.1021/jp980849qdoi:10.1021/jp980849q, 1998. Monks, P. S.: A review of the observations and origins of the spring ozone maximum, Atmos. Environ., 34, 3545–3561, 2000. Montzka, S. A., Butler, J. H., Hall, B. D., Mondeel, D. J., and Elkins, J. W.: A decline in tropospheric organic bromine, Geophys. Res. Lett., 30, 1826, http://dx.doi.org/10.1029/2003GL017745doi:10.1029/2003GL017745, 2003. Montzka, S. A., Reimann, S. (Coordinating Lead Authors), Engel, A., Krüger, K., O'Doherty, S., Sturges, W. T., Blake, D. R., Dorf, M., Fraser, P., Froidevaux, L., Jucks, K. W., Kreher, K., Kurylo, M. J., Mellouki, A., Miller, J., Nielsen, O.-J., Orkin, V. L., Prinn, R. G., Rhew, R., Santee, M. L., Stohl, A., and Verdonik, D.: Ozone-Depleting Substances (OESs) and Related Chemicals, Chapter 1 in Scientific Assessment of Ozone Depletion: 2010, Global Ozone Research and Monitoring Project-Report No. 52, 516 pp., World Meteorological Organization, Geneva, Switzerland, 2011. Nassar, R., Logan, J. A., Megretskaia, I. A., Murray, L. T., Zhang, L., and Jones, D. B. A.: Analysis of tropical tropospheric ozone, carbon monoxide, and water vapor during the 2006 El Niño using TES observations and the GEOS-Chem model, J. Geophys. Res., 114, D17304, http://dx.doi.org/10.1029/2009JD011760doi:10.1029/2009JD011760, 2009. Neuman, J. A., Nowak, J. B., Huey, L. G., Burkholder, J. B., Dibb, J. E., Holloway, J. S., Liao, J., Peischl, J., Roberts, J. M., Ryerson, T. B., Scheuer, E., Stark, H., Stickel, R. E., Tanner, D. J., and Weinheimer, A.: Bromine measurements in ozone depleted air over the Arctic Ocean, Atmos. Chem. Phys., 10, 6503–6514, http://dx.doi.org/10.5194/acp-10-6503-2010doi:10.5194/acp-10-6503-2010, 2010. Oltmans, S. J., Lefohn, A. S., Harris, J. M., Galbally, I., Scheel, H. E., Bodeker, G., Brunke, E., Claude, H., Tarasick, D., Johnson, B. J., Simmonds, P., Shadwick, D., Anlauf, K., Hayden, K., Schmidlin, F., Fujimoto, T., Akagi, K., Meyer, C., Nichol, S., Davies, J., Redondas, A., and Cuevas, E.: Long-term changes in tropospheric ozone, Atmos. Environ., 40, 3156–3173, 2006. Orlando, J. J. and Tyndall, G. S.: Rate Coefficients for the Thermal Decomposition of BrONO<sub>2</sub> and the Heat of Formation of BrONO<sub>2</sub>, J. Phys. Chem., 100, 19398–19405, http://dx.doi.org/10.1021/jp9620274doi:10.1021/jp9620274, 1996. Park, R. J., Jacob, D. J., Field, B. D., Yantosca, R. M., and Chin, M.: Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: Implications for policy, J. Geophys. Res., 109, D15204, http://dx.doi.org/10.1029/2003jd004473doi:10.1029/2003jd004473, 2004. Parrish, D. D., Millet, D. B., and Goldstein, A. H.: Increasing ozone in marine boundary layer inflow at the west coasts of North America and Europe, Atmos. Chem. Phys., 9, 1303–1323, http://dx.doi.org/10.5194/acp-9-1303-2009doi:10.5194/acp-9-1303-2009, 2009. Paulot, F., Crounse, J. D., Kjaergaard, H. G., Kürten, A., St. Clair, J. M., Seinfeld, J. H., and Wennberg, P. O.: Unexpected Epoxide Formation in the Gas-Phase Photooxidation of Isoprene, Science, 325, 730–733, 2009a. Paulot, F., Crounse, J. D., Kjaergaard, H. G., Kroll, J. H., Seinfeld, J. H., and Wennberg, P. O.: Isoprene photooxidation: new insights into the production of acids and organic nitrates, Atmos. Chem. Phys., 9, 1479–1501, http://dx.doi.org/10.5194/acp-9-1479-2009doi:10.5194/acp-9-1479-2009, 2009b. Platt, U. and Hönninger, G.: The role of halogen species in the troposphere, Chemosphere, 52, 325–338, 2003. Prinn, R. G., Huang, J., Weiss, R. F., Cunnold, D. M., Fraser, P. J., Simmonds, P. G., McCulloch, A., Harth, C., Reimann, S., Salameh, P., O'Doherty, S., Wang, R. H. J., Porter, L. W., Miller, B. R., and Krummel, P. B.: Evidence for variability of atmospheric hydroxyl radicals over the past quarter century, Geophys. Res. Lett., 32, L07809, http://dx.doi.org/10.1029/2004gl022228doi:10.1029/2004gl022228, 2005. Pyle, D. M. and Mather, T. A.: Halogens in igneous processes and their fluxes to the atmosphere and oceans from volcanic activity: A review, Chem. Geol., 263, 110–121, 2009. Pyle, J. A., Ashfold, M. J., Harris, N. R. P., Robinson, A. D., Warwick, N. J., Carver, G. D., Gostlow, B., O'Brien, L. M., Manning, A. J., Phang, S. M., Yong, S. E., Leong, K. P., Ung, E. H., and Ong, S.: Bromoform in the tropical boundary layer of the Maritime Continent during OP3, Atmos. Chem. Phys., 11, 529–542, http://dx.doi.org/10.5194/acp-11-529-2011doi:10.5194/acp-11-529-2011, 2011. Quack, B. and Wallace, D. W. R.: Air-sea flux of bromoform: Controls, rates, and implications, Global Biogeochem. Cy., 17, GB1004, http://dx.doi.org/10.1029/2003GB002187doi:10.1029/2003GB002187, 2003. Richter, A., Wittrock, F., Ladstätter-Weißenmayer, A., and Burrows, J. P.: GOME measurements of stratospheric and tropospheric BrO, Adv. Space Res., 29, 1667–1672, 2002. Saiz-Lopez, A., Lamarque, J.-F., Kinnison, D. E., Tilmes, S., Ordóñez, C., Orlando, J. J., Conley, A. J., Plane, J. M. C., Mahajan, A. S., Sousa Santos, G., Atlas, E. L., Blake, D. R., Sander, S. P., Schauffler, S., Thompson, A. M., and Brasseur, G.: Estimating the climate significance of halogen-driven ozone loss in the tropical marine troposphere, Atmos. Chem. Phys., 12, 3939–3949, http://dx.doi.org/10.5194/acp-12-3939-2012doi:10.5194/acp-12-3939-2012, 2012. Salawitch, R. J., Canty, T., Kurosu, T., Chance, K., Liang, Q., da Silva, A., Pawson, S., Nielsen, J. E., Rodriguez, J. M., Bhartia, P. K., Liu, X., Huey, L. G., Liao, J., Stickel, R. E., Tanner, D. J., Dibb, J. E., Simpson, W. R., Donohoue, D., Weinheimer, A., Flocke, F., Knapp, D., Montzka, D., Neuman, J. A., Nowak, J. B., Ryerson, T. B., Oltmans, S., Blake, D. R., Atlas, E. L., Kinnison, D. E., Tilmes, S., Pan, L. L., Hendrick, F., Van Roozendael, M., Kreher, K., Johnston, P. V., Gao, R. S., Johnson, B., Bui, T. P., Chen, G., Pierce, R. B., Crawford, J. H., and Jacob, D. J.: A new interpretation of total column BrO during Arctic spring, Geophys. Res. Lett., 37, L21805, http://dx.doi.org/10.1029/2010gl043798doi:10.1029/2010gl043798, 2010. Saltzman, E. S., Aydin, M., De Bruyn, W. J., King, D. B., and Yvon-Lewis, S. A.: Methyl bromide in preindustrial air: Measurements from an Antarctic ice core, J. Geophys. Res., 109, D05301, http://dx.doi.org/10.1029/2003JD004157doi:10.1029/2003JD004157, 2004. Sander, R.: Compilation of Henry's Law Constants for Inorganic and Organic Species of Potential Importance in Environmental Chemistry, http://www.henrys-law.org, 1999. Sander, R., Rudich, Y., von Glasow, R., and Crutzen, P. J.: The role of BrNO<sub>3</sub> in marine tropospheric chemistry: A model study, Geophys. Res. Lett., 26, 2857–2860, 1999. Sander, R., Keene, W. C., Pszenny, A. A. P., Arimoto, R., Ayers, G. P., Baboukas, E., Cainey, J. M., Crutzen, P. J., Duce, R. A., Hönninger, G., Huebert, B. J., Maenhaut, W., Mihalopoulos, N., Turekian, V. C., and Van Dingenen, R.: Inorganic bromine in the marine boundary layer: a critical review, Atmos. Chem. Phys., 3, 1301–1336, http://dx.doi.org/10.5194/acp-3-1301-2003doi:10.5194/acp-3-1301-2003, 2003. Sander, S. P., Friedl, R. R., Abbatt, J. P. D., Barker, J. R., Burkholder, J. B., Golden, D. M., Kolb, C. E., Kurylo, M. J., Moortgat, G. K., Wine, P. H., Huie, R. E., and Orkin, V. L.: Chemical kinetics and photochemical data for use in atmospheric studies, Evaluation Number 17, NASA Jet Propulsion Laboratory, 2011. Sauvage, B., Martin, R. V., van Donkelaar, A., Liu, X., Chance, K., Jaeglé, L., Palmer, P. I., Wu, S., and Fu, T.-M.: Remote sensed and in situ constraints on processes affecting tropical tropospheric ozone, Atmos. Chem. Phys., 7, 815–838, http://dx.doi.org/10.5194/acp-7-815-2007doi:10.5194/acp-7-815-2007, 2007. Scheffler, D., Grothe, H., Willner, H., Frenzel, A., and Zetzsch, C.: Properties of Pure Nitryl Bromide. Thermal Behavior, UV/Vis and FTIR Spectra, and Photoisomerization to trans-BrONO in an Argon Matrix, Inorg. Chem., 36, 335–338, http://dx.doi.org/10.1021/ic9606946doi:10.1021/ic9606946, 1997. Schwartz, S. E.: Mass-transport considerations pertinent to aqueous-phase reactions of gases in liquid-water clouds, in: Chemistry of Multiphase Atmospheric Systems, edited by: Jaechske, W., Springer, Heidelberg, 415–471, 1986. Schweitzer, F., Mirabel, P., and George, C.: Uptake of Hydrogen Halides by Water Droplets, J. Phys. Chem. A, 104, 72–76, http://dx.doi.org/10.1021/jp992621odoi:10.1021/jp992621o, 2000. Seakins, P. W., Pilling, M. J., Niiranen, J. T., Gutman, D., and Krasnoperov, L. N.: Kinetics and thermochemistry of R + HBr $\leftrightarrow $ RH + Br reactions: Determinations of the heat of formation of C<sub>2</sub>H$_5$, /-C<sub>3</sub>H$_7$, sec-C<sub>4</sub>H$_9$, and $t$-C<sub>4</sub>H$_9$ radicals, J. Phys. Chem., 96, 9847–9855, http://dx.doi.org/10.1021/j100203a050doi:10.1021/j100203a050, 1992. Selin, N. E., Jacob, D. J., Yantosca, R. M., Strode, S., Jaeglé, L., and Sunderland, E. M.: Global 3-D land-ocean-atmosphere model for mercury: Present-day versus preindustrial cycles and anthropogenic enrichment factors for deposition, Global Biogeochem. Cy., 22, GB2011, http://dx.doi.org/10.1029/2007gb003040doi:10.1029/2007gb003040, 2008. Shindell, D. T., Faluvegi, G., and Bell, N.: Preindustrial-to-present-day radiative forcing by tropospheric ozone from improved simulations with the GISS chemistry-climate GCM, Atmos. Chem. Phys., 3, 1675–1702, http://dx.doi.org/10.5194/acp-3-1675-2003doi:10.5194/acp-3-1675-2003, 2003. Simpson, W. R., von Glasow, R., Riedel, K., Anderson, P., Ariya, P., Bottenheim, J., Burrows, J., Carpenter, L. J., Frieß, U., Goodsite, M. E., Heard, D., Hutterli, M., Jacobi, H.-W., Kaleschke, L., Neff, B., Plane, J., Platt, U., Richter, A., Roscoe, H., Sander, R., Shepson, P., Sodeau, J., Steffen, A., Wagner, T., and Wolff, E.: Halogens and their role in polar boundary-layer ozone depletion, Atmos. Chem. Phys., 7, 4375–4418, http://dx.doi.org/10.5194/acp-7-4375-2007doi:10.5194/acp-7-4375-2007, 2007. Slemr, F., Seiler, W., and Schuster, G.: Latitudinal Distribution of Mercury Over the Atlantic Ocean, J. Geophys. Res., 86, 1159–1166, http://dx.doi.org/10.1029/JC086iC02p01159doi:10.1029/JC086iC02p01159, 1981. Slemr, F., Schuster, G., and Seiler, W.: Distribution, speciation, and budget of atmospheric mercury, J. Atmos. Chem., 3, 407–434, http://dx.doi.org/10.1007/bf00053870doi:10.1007/bf00053870, 1985. Slemr, F., Brunke, E.-G., Ebinghaus, R., and Kuss, J.: Worldwide trend of atmospheric mercury since 1995, Atmos. Chem. Phys., 11, 4779–4787, http://dx.doi.org/10.5194/acp-11-4779-2011doi:10.5194/acp-11-4779-2011, 2011. Soerensen, A. L., Sunderland, E. M., Holmes, C. D., Jacob, D. J., Yantosca, R. M., Skov, H., Christensen, J. H., Strode, S. A., and Mason, R. P.: An Improved Global Model for Air-Sea Exchange of Mercury: High Concentrations over the North Atlantic, Environ. Sci. Technol., 44, 8574–8580, http://dx.doi.org/10.1021/es102032gdoi:10.1021/es102032g, 2010. Soerensen, A. L., Jacob, D. J., Streets, D. G., Witt, M., Ebinghaus, R., Mason, R. P., Andersson, M., and Sunderland, E. M.: Multi-decadal decline of mercury in the North Atlantic atmosphere explained by changing subsurface seawater concentrations, Geophys. Res. Lett., submitted, 2012. Spivakovsky, C. M., Logan, J. A., Montzka, S. A., Balkanski, Y. J., Foreman-Fowler, M., Jones, D. B. A., Horowitz, L. W., Fusco, A. C., Brenninkmeijer, C. A. M., Prather, M. J., Wofsy, S. C., and McElroy, M. B.: Three-dimensional climatological distribution of tropospheric OH: Update and evaluation, J. Geophys. Res., 105, 8931–8980, http://dx.doi.org/10.1029/1999jd901006doi:10.1029/1999jd901006, 2000. Steffen, A., Douglas, T., Amyot, M., Ariya, P., Aspmo, K., Berg, T., Bottenheim, J., Brooks, S., Cobbett, F., Dastoor, A., Dommergue, A., Ebinghaus, R., Ferrari, C., Gardfeldt, K., Goodsite, M. E., Lean, D., Poulain, A. J., Scherz, C., Skov, H., Sommar, J., and Temme, C.: A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow, Atmos. Chem. Phys., 8, 1445–1482, http://dx.doi.org/10.5194/acp-8-1445-2008doi:10.5194/acp-8-1445-2008, 2008. Stone, D. and Evans, M. J.: Impact of halogen chemistry on HO$_\mathrmx$ radicals: Comparisons between box and global models with measurements at the Cape Verde Atmospheric Observatory during the Seasonal Oxidant Study, in preparation, 2012. Streets, D. G., Devane, M. K., Lu, Z., Bond, T. C., Sunderland, E. M., and Jacob, D. J.: All-Time Releases of Mercury to the Atmosphere from Human Activities, Environ. Sci. Technol., 45, 10485–10491, http://dx.doi.org/10.1021/es202765mdoi:10.1021/es202765m, 2011. Stuart, A. L. and Jacobson, M. Z.: A timescale investigation of volatile chemical retention during hydrometeor freezing: Nonrime freezing and dry growth riming without spreading, J. Geophys. Res., 108, 4178, http://dx.doi.org/10.1029/2001jd001408doi:10.1029/2001jd001408, 2003. Stutz, J., Ackermann, R., Fast, J. D., and Barrie, L.: Atmospheric reactive chlorine and bromine at the Great Salt Lake, Utah, Geophys. Res. Lett., 29, 1380, http://dx.doi.org/10.1029/2002gl014812doi:10.1029/2002gl014812, 2002. Theys, N., Van Roozendael, M., Hendrick, F., Fayt, C., Hermans, C., Baray, J.-L., Goutail, F., Pommereau, J.-P., and De Mazière, M.: Retrieval of stratospheric and tropospheric BrO columns from multi-axis DOAS measurements at Reunion Island (21° S, 56° E), Atmos. Chem. Phys., 7, 4733–4749, http://dx.doi.org/10.5194/acp-7-4733-2007doi:10.5194/acp-7-4733-2007, 2007. Theys, N., Van Roozendael, M., Errera, Q., Hendrick, F., Daerden, F., Chabrillat, S., Dorf, M., Pfeilsticker, K., Rozanov, A., Lotz, W., Burrows, J. P., Lambert, J.-C., Goutail, F., Roscoe, H. K., and De Mazière, M.: A global stratospheric bromine monoxide climatology based on the BASCOE chemical transport model, Atmos. Chem. Phys., 9, 831–848, http://dx.doi.org/10.5194/acp-9-831-2009doi:10.5194/acp-9-831-2009, 2009. Theys, N., Van Roozendael, M., Hendrick, F., Yang, X., De Smedt, I., Richter, A., Begoin, M., Errera, Q., Johnston, P. V., Kreher, K., and De Mazière, M.: Global observations of tropospheric BrO columns using GOME-2 satellite data, Atmos. Chem. Phys., 11, 1791–1811, http://dx.doi.org/10.5194/acp-11-1791-2011doi:10.5194/acp-11-1791-2011, 2011. US Environmental Protection Agency: Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final), Vols. I, II, and III, 600/R-605/004aF-cF, 2006. Van Roozendael, M., Wagner, T., Richter, A., Pundt, I., Arlander, D. W., Burrows, J. P., Chipperfield, M., Fayt, C., Johnston, P. V., Lambert, J. C., Kreher, K., Pfeilsticker, K., Platt, U., Pommereau, J. P., Sinnhuber, B. M., Tørnkvist, K. K., and Wittrock, F.: Intercomparison of BrO measurements from ERS-2 GOME, ground-based and balloon platforms, Adv. Space Res., 29, 1661–1666, 2002. Vogt, R., Crutzen, P. J., and Sander, R.: A mechanism for halogen release from sea-salt aerosol in the remote marine boundary layer, Nature, 383, 327–330, 1996. Volz, A. and Kley, D.: Evaluation of the Montsouris series of ozone measurements made in the nineteenth century, Nature, 332, 240–242, 1988. von Glasow, R., von Kuhlmann, R., Lawrence, M. G., Platt, U., and Crutzen, P. J.: Impact of reactive bromine chemistry in the troposphere, Atmos. Chem. Phys., 4, 2481–2497, http://dx.doi.org/10.5194/acp-4-2481-2004doi:10.5194/acp-4-2481-2004, 2004. Wachsmuth, M., Gäggeler, H. W., von Glasow, R., and Ammann, M.: Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles, Atmos. Chem. Phys., 2, 121–131, http://dx.doi.org/10.5194/acp-2-121-2002doi:10.5194/acp-2-121-2002, 2002. Wang, J., Hoffmann, A. A., Park, R. J., Jacob, D. J., and Martin, S. T.: Global distribution of solid and aqueous sulfate aerosols: Effect of the hysteresis of particle phase transitions, J. Geophys. Res., 113, D11206, http://dx.doi.org/10.1029/2007jd009367doi:10.1029/2007jd009367, 2008. Wang, Y. and Jacob, D.: Anthropogenic forcing on tropospheric ozone and OH since preindustrial times, J. Geophys. Res., 103, 31123–31135, 1998. Wang, Y., Jacob, D. J., and Logan, J. A.: Global simulation of tropospheric O<sub>3</sub>-NO$_\mathrmx$-hydrocarbon chemistry 1. Model formulation, J. Geophys. Res., 103, 10713–10725, http://dx.doi.org/10.1029/98jd00158doi:10.1029/98jd00158, 1998. Warwick, N. J., Pyle, J. A., Carver, G. D., Yang, X., Savage, N. H., O'Connor, F. M., and Cox, R. A.: Global modeling of biogenic bromocarbons, J. Geophys. Res., 111, D24305, http://dx.doi.org/10.1029/2006JD007264doi:10.1029/2006JD007264, 2006. Wesely, M. L.: Parameterization of surface resistance to gaseous dry deposition in regional-scale numerical models, Atmos. Environ., 23, 1293–1304, 1989. Wild, O., Zhu, X., and Prather, M. J.: Fast-J: Accurate Simulation of In- and Below-Cloud Photolysis in Tropospheric Chemical Models, J. Atmos. Chem., 37, 245–282, http://dx.doi.org/10.1023/a:1006415919030doi:10.1023/a:1006415919030, 2000. Wu, S., Mickley, L. J., Jacob, D. J., Logan, J. A., Yantosca, R. M., and Rind, D.: Why are there large differences between models in global budgets of tropospheric ozone?, J. Geophys. Res., 112, D05302, http://dx.doi.org/10.1029/2006jd007801doi:10.1029/2006jd007801, 2007. Yang, X., Cox, R. A., Warwick, N. J., Pyle, J. A., Carver, G. D., O'Connor, F. M., and Savage, N. H.: Tropospheric bromine chemistry and its impacts on ozone: A model study, J. Geophys. Res., 110, D23311, http://dx.doi.org/10.1029/2005JD006244doi:10.1029/2005JD006244, 2005. Yang, X., Pyle, J. A., and Cox, R. A.: Sea salt aerosol production and bromine release: Role of snow on sea ice, Geophys. Res. Lett., 35, L16815, http://dx.doi.org/10.1029/2008GL034536doi:10.1029/2008GL034536, 2008. Yang, X., Pyle, J. A., Cox, R. A., Theys, N., and Van Roozendael, M.: Snow-sourced bromine and its implications for polar tropospheric ozone, Atmos. Chem. Phys., 10, 7763–7773, http://dx.doi.org/10.5194/acp-10-7763-2010doi:10.5194/acp-10-7763-2010, 2010. Yokouchi, Y., Hasebe, F., Fujiwara, M., Takashima, H., Shiotani, M., Nishi, N., Kanaya, Y., Hashimoto, S., Fraser, P., Toom-Sauntry, D., Mukai, H., and Nojiri, Y.: Correlations and emission ratios among bromoform, dibromochloromethane, and dibromomethane in the atmosphere, J. Geophys. Res., 110, D23309, http://dx.doi.org/10.1029/2005JD006303doi:10.1029/2005JD006303, 2005. \hack Yvon-Lewis, S. A., Saltzman, E. S., and Montzka, S. A.: Recent trends in atmospheric methyl bromide: analysis of post-Montreal Protocol variability, Atmos. Chem. Phys., 9, 5963–5974, http://dx.doi.org/10.5194/acp-9-5963-2009doi:10.5194/acp-9-5963-2009, 2009. Zhang, L., Jacob, D. J., Liu, X., Logan, J. A., Chance, K., Eldering, A., and Bojkov, B. R.: Intercomparison methods for satellite measurements of atmospheric composition: application to tropospheric ozone from TES and OMI, Atmos. Chem. Phys., 10, 4725–4739, http://dx.doi.org/10.5194/acp-10-4725-2010doi:10.5194/acp-10-4725-2010, 2010.