Growth in stratospheric chlorine from short‐lived chemicals not controlled by the Montreal Protocol. Issue 11 (1st June 2015)

• Record Type: Journal Article
• Authors: Hossaini, R.; Chipperfield, M. P.; Saiz‐Lopez, A.; Harrison, J. J.; von Glasow, R.; Sommariva, R.; Atlas, E.; Navarro, M.; Montzka, S. A.; Feng, W.; Dhomse, S.; Harth, C.; Mühle, J.; Lunder, C.; O'Doherty, S.; Young, D.; Reimann, S.; Vollmer, M. K.; Krummel, P. B.; Bernath, P. F.
• Is Part Of: Geophysical research letters. Volume 42:Issue 11(2015:Jun.)
• Page Start: 4573
• Page End: 4580
• Publication Date: 2015-06-01
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL063783
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main" id="grl52978-abs-0001"> <title>Abstract</title> <p id="grl52978-para-0001">We have developed a chemical mechanism describing the tropospheric degradation of chlorine containing very short‐lived substances (VSLS). The scheme was included in a global atmospheric model and used to quantify the stratospheric injection of chlorine from anthropogenic VSLS ( <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgj1d0rwsvm" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:grl:media:grl52978:grl52978-math-0001" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>Cl</mml:mtext></mml:mrow><mml:mrow><mml:mi>y</mml:mi></mml:mrow><mml:mrow><mml:mtext>VSLS</mml:mtext></mml:mrow></mml:msubsup></mml:math></alternatives></inline-formula>) between 2005 and 2013. By constraining the model with surface measurements of chloroform (CHCl<sub>3</sub>), dichloromethane (CH<sub>2</sub>Cl<sub>2</sub>), tetrachloroethene (C<sub>2</sub>Cl<sub>4</sub>), trichloroethene (C<sub>2</sub>HCl<sub>3</sub>), and 1, 2‐dichloroethane (CH<sub>2</sub>ClCH<sub>2</sub>Cl), we infer a 2013 <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgj1d0rwssh" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:grl:media:grl52978:grl52978-math-0002" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>Cl</mml:mtext></mml:mrow><mml:mrow><mml:mi>y</mml:mi></mml:mrow><mml:mrow><mml:mtext>VSLS</mml:mtext></mml:mrow></mml:msubsup></mml:math></alternatives></inline-formula> mixing ratio of 123 parts per trillion (ppt). Stratospheric injection of source gases dominates this supply, accounting for ∼83% of the total. The remainder comes from VSLS‐derived organic products, phosgene (COCl<sub>2</sub>, 7%) and formyl chloride (CHClO, 2%), and also hydrogen chloride (HCl, 8%). Stratospheric <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgj1d0rwtm8" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:grl:media:grl52978:grl52978-math-0003" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>Cl</mml:mtext></mml:mrow><mml:mrow><mml:mi>y</mml:mi></mml:mrow><mml:mrow><mml:mtext>VSLS</mml:mtext></mml:mrow></mml:msubsup></mml:math></alternatives></inline-formula> increased by ∼52% between 2005 and 2013, with a mean growth rate of 3.7 ppt Cl/yr. This increase is due to recent and ongoing growth in anthropogenic CH<sub>2</sub>Cl<sub>2</sub>—the most abundant chlorinated VSLS not controlled by the Montreal Protocol.</p> </abstract>