{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,27]],"date-time":"2026-09-27T04:28:17Z","timestamp":1790483297877,"version":"4.1.0"},"reference-count":38,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5503","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[2001,1,19]]},"abstract":"<jats:p>\n            Bromine atoms are believed to play a central role in the depletion of surface-level ozone in the Arctic at polar sunrise. Br\n            <jats:sub>2<\/jats:sub>\n            , BrCl, and HOBr have been hypothesized as bromine atom precursors, and there is evidence for chlorine atom precursors as well, but these species have not been measured directly. We report here measurements of Br\n            <jats:sub>2<\/jats:sub>\n            , BrCl, and Cl\n            <jats:sub>2<\/jats:sub>\n            made using atmospheric pressure chemical ionization\u2013mass spectrometry at Alert, Nunavut, Canada. In addition to Br\n            <jats:sub>2<\/jats:sub>\n            at mixing ratios up to \u223c25 parts per trillion, BrCl was found at levels as high as \u223c35 parts per trillion. Molecular chlorine was not observed, implying that BrCl is the dominant source of chlorine atoms during polar sunrise, consistent with recent modeling studies. Similar formation of bromine compounds and tropospheric ozone destruction may also occur at mid-latitudes but may not be as apparent owing to more efficient mixing in the boundary layer.\n          <\/jats:p>","DOI":"10.1126\/science.291.5503.471","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T09:53:24Z","timestamp":1027763604000},"page":"471-474","source":"Crossref","is-referenced-by-count":344,"title":["The Role of Br\n            <sub>2<\/sub>\n            and BrCl in Surface Ozone Destruction at Polar Sunrise"],"prefix":"10.1126","volume":"291","author":[{"given":"Krishna L.","family":"Foster","sequence":"first","affiliation":[{"name":"Department of Chemistry, University of California, Irvine, CA 92697\u20132025, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert A.","family":"Plastridge","sequence":"additional","affiliation":[{"name":"Battelle, 505 King Avenue, Columbus, OH 43201\u20132693, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan W.","family":"Bottenheim","sequence":"additional","affiliation":[{"name":"Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul B.","family":"Shepson","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, IN 47907\u20131393, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara J.","family":"Finlayson-Pitts","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of California, Irvine, CA 92697\u20132025, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chester W.","family":"Spicer","sequence":"additional","affiliation":[{"name":"Battelle, 505 King Avenue, Columbus, OH 43201\u20132693, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1029\/GL013i002p00113","volume":"13","author":"Bottenheim J. W.","year":"1986","unstructured":"Bottenheim J. W., Gallant A. G., Brice K. A., Geophys. Res. Lett. 13, 113 (1986).","journal-title":"Geophys. Res. Lett."},{"key":"e_1_3_1_3_2","doi-asserted-by":"crossref","first-page":"5229","DOI":"10.1029\/JD091iD04p05229","volume":"91","author":"Oltmans S. J.","year":"1986","unstructured":"Oltmans S. J., Komhyr W. D., J. Geophys. Res. 91, 5229 (1986).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_4_2","doi-asserted-by":"publisher","DOI":"10.1038\/334138a0"},{"key":"e_1_3_1_5_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF00055158"},{"key":"e_1_3_1_6_2","doi-asserted-by":"crossref","first-page":"486","DOI":"10.3402\/tellusb.v49i5.15987","volume":"49","author":"Lehrer E.","year":"1997","unstructured":"Lehrer E., Wagenbach D., Platt U., Tellus 49B, 486 (1997).","journal-title":"Tellus"},{"key":"e_1_3_1_7_2","doi-asserted-by":"crossref","first-page":"16005","DOI":"10.1029\/97JD00851","volume":"102","author":"Impey G. A.","year":"1997","unstructured":"Impey G. A., Shepson P. B., Hastie D. R., Barrie L. A., Anlauf K. G., J. Geophys. Res. 102, 16005 (1997).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_8_2","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1023\/A:1006264912394","volume":"34","author":"Impey G. A.","year":"1999","unstructured":"Impey G. A., et al., J. Atmos. Chem. 34, 21 (1999).","journal-title":"J. Atmos. Chem."},{"key":"e_1_3_1_9_2","doi-asserted-by":"crossref","first-page":"450","DOI":"10.3402\/tellusb.v49i5.15984","volume":"49","author":"Barrie L.","year":"1997","unstructured":"Barrie L., Platt U., Tellus 49B, 450 (1997).","journal-title":"Tellus"},{"key":"e_1_3_1_10_2","doi-asserted-by":"crossref","first-page":"25399","DOI":"10.1029\/94JD01314","volume":"99","author":"Hausmann M.","year":"1994","unstructured":"Hausmann M., Platt U., J. Geophys. Res. 99, 25399 (1994).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_11_2","doi-asserted-by":"crossref","first-page":"533","DOI":"10.3402\/tellusb.v49i5.16005","volume":"49","author":"Tuckermann M.","year":"1997","unstructured":"Tuckermann M., et al., Tellus 49B, 533 (1997).","journal-title":"Tellus"},{"key":"e_1_3_1_12_2","doi-asserted-by":"crossref","first-page":"16341","DOI":"10.1029\/94JC01194","volume":"99","author":"Perovich D. K.","year":"1994","unstructured":"Perovich D. K., Richter-Menge J. A., J. Geophys. Res. 99, 16341 (1994).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_13_2","doi-asserted-by":"crossref","first-page":"12111","DOI":"10.1029\/96JC00208","volume":"101","author":"Martin S.","year":"1996","unstructured":"Martin S., Yu Y., Drucker R., J. Geophys. Res. 101, 12111 (1996).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_14_2","doi-asserted-by":"crossref","first-page":"599","DOI":"10.1029\/94GL03334","volume":"22","author":"LeBras G.","year":"1995","unstructured":"LeBras G., Platt U., Geophys. Res. Lett. 22, 599 (1995).","journal-title":"Geophys. Res. Lett."},{"key":"e_1_3_1_15_2","doi-asserted-by":"publisher","DOI":"10.1038\/18423"},{"key":"e_1_3_1_16_2","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1038\/355150a0","volume":"355","author":"McConnell J. C.","year":"1992","unstructured":"McConnell J. C., et al., Nature 355, 150 (1992).","journal-title":"Nature"},{"key":"e_1_3_1_17_2","doi-asserted-by":"crossref","first-page":"1355","DOI":"10.1021\/ja00867a005","volume":"84","author":"Eigen M.","year":"1962","unstructured":"Eigen M., Kustin K., J. Am. Chem. Soc. 84, 1355 (1962).","journal-title":"J. Am. Chem. Soc."},{"key":"e_1_3_1_18_2","doi-asserted-by":"crossref","first-page":"23719","DOI":"10.1029\/1999JD900359","volume":"104","author":"Fickert S.","year":"1999","unstructured":"Fickert S., Adams J. W., Crowley J. N., J. Geophys. Res. 104, 23719 (1999).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_19_2","unstructured":"Measurements were made with an atmospheric pressure chemical ionization\u2013tandem mass spectrometer (APCI-MS\/MS PerkinElmer Sciex Model 365) modified for air monitoring (35 37). A corona discharge was used to ionize the sample air. All measurements were made in the negative-ion mode. For each target chemical a parent molecular anion was separated from other ions by using the first quadrupole and then fragmented in a gas collision cell. One or more particular fragments were isolated by the second quadrupole giving parent-daughter ion pairs that are characteristic of each target chemical. Molecular Br 2 was measured as the ion pairs 158\/79 160\/79 160\/81 and 162\/81; Cl 2 as 70\/35 72\/35 72\/37 and 74\/37; and BrCl as 114\/35 116\/35 116\/37 and 118\/37. Detection limits are estimated to be 0.2 ppt for Br 2 and 2 ppt for Cl 2 and BrCl respectively for a 20-s integration time and a signal to noise ratio of 3. The identification of these compounds was confirmed by daughter ion scans of selected parent ions and measurement of the ratios of observed signals compared with those expected on the basis of the natural abundance of the isotopes found in each compound. Throughout the study at least two ion pairs were monitored for each compound. The instrument was located in the far transmitter building (FTX; 82\u00b027.29\u2032N 62\u00b029.84\u2032W) \u223c6 km from the Alert base camp \u223c 7 km south of the Arctic Ocean and \u223c210 m above sea level. The sample line was an insulated 0.64-cm outer diameter Teflon tube heated to 21\u00b0C and extended \u223c7.6 m away from the west wall of the building. Residence time in the sample line was less than 1 s. The data have been corrected for sample line loss measured as 10% for Cl 2 and 4% for Br 2 . The inlet was shielded to prevent snow from entering the sampling line. A Teflon solenoid valve programmed to open and close automatically was used to record 30-min baseline measurements every 4 to 6 hours by diverting the ambient air flow through a potassium carbonate (K 2 CO 3 ) denuder placed in the air-stream before the mass spectrometer inlet. The denuder removes gaseous halogen compounds from the air stream. Calibrations were performed with Br 2 and Cl 2 permeation devices with permeation rates of 6.3 and 35.7 ng min \u22121 respectively which gives calibration concentrations of 111 ppt Br 2 and 1420 ppt Cl 2 in air. The precision of calibration data sets carried out before and after a given ambient air measurement was \u00b110% (2\u03c3) for all halogens. The permeation rates were checked at the beginning of the study by bubbling the air-stream into a 30 mM NaHCO 3 solution and measuring the Br \u2212 and Cl \u2212 concentration by ion chromatography. The calibration for BrCl was assumed to be the same as for Cl 2 on the basis of laboratory studies with a similar API-MS (Model 300) in which the sensitivities for BrCl and Cl 2 were within 15% when BrCl (0.1 to 1.3 ppb) was synthesized from the reaction of Br 2 (0.067 to 0.73 ppb) with excess Cl 2 (1.4 to 18.3 ppb). Changes in the instrument sensitivity which were measured daily have been taken into account."},{"key":"e_1_3_1_20_2","unstructured":"B. J. Finlayson-Pitts J. N. Pitts Chemistry of the Upper and Lower Atmosphere\u2014Theory Experiments and Applications (Academic Press San Diego CA 2000)."},{"key":"e_1_3_1_21_2","doi-asserted-by":"crossref","first-page":"25315","DOI":"10.1029\/94JD02400","volume":"99","author":"Hopper J. F.","year":"1994","unstructured":"Hopper J. F., Hart W., J. Geophys. Res. 99, 25315 (1994).","journal-title":"J. Geophys. 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D., Waschewsky G. C. G., J. Phys. Chem. A 102, 3719 (1998).","journal-title":"J. Phys. Chem. A"},{"key":"e_1_3_1_26_2","doi-asserted-by":"crossref","first-page":"9121","DOI":"10.1029\/95JD03793","volume":"101","author":"Sander R.","year":"1996","unstructured":"Sander R., Crutzen P. J., J. Geophys. Res. 101, 9121 (1996).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_27_2","doi-asserted-by":"crossref","first-page":"15131","DOI":"10.1029\/2000JD900004","volume":"105","author":"Michalowski B. A.","year":"2000","unstructured":"Michalowski B. A., et al., J. Geophys. Res. 105, 15131 (2000).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_28_2","doi-asserted-by":"crossref","first-page":"1050","DOI":"10.1021\/ic00084a014","volume":"33","author":"Wang T. X.","year":"1994","unstructured":"Wang T. X., Margerum D. W., Inorg. Chem. 33, 1050 (1994).","journal-title":"Inorg. 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V., Shaw W. J., Busness K. M., Chapman E. G., Environ. Sci. Technol. 28, 412A (1994).","journal-title":"Environ. Sci. Technol."},{"key":"e_1_3_1_39_2","unstructured":"We are grateful to the Department of Energy's Atmospheric Chemistry Program and particularly P. Lunn for support of this work; the Meteorological Service of Canada for providing transport to Alert and housing during the study; and the personnel of Canadian Forces Station Alert for logistical support. We are especially grateful for the on-site support provided by A. Gallant and P. Brickell organizational support and comments on the manuscript by L. Barrie use of a snow probe developed by A. L. Sumner and ozone calibrations provided by K. Anlauf. We also thank J. N. Pitts Jr. J. C. Hemminger P. Jungwirth D. Tobias and R. B. Gerber for helpful discussions and M. J. Molina for providing preprints before publication."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.291.5503.471","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,13]],"date-time":"2024-01-13T09:33:38Z","timestamp":1705138418000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.291.5503.471"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2001,1,19]]},"references-count":38,"journal-issue":{"issue":"5503","published-print":{"date-parts":[[2001,1,19]]}},"alternative-id":["10.1126\/science.291.5503.471"],"URL":"https:\/\/doi.org\/10.1126\/science.291.5503.471","relation":{},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2001,1,19]]}}}