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| Titel |
Updated ozone absorption cross section will reduce air quality compliance |
| VerfasserIn |
E. D. Sofen, M. J. Evans, A. C. Lewis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 23 ; Nr. 15, no. 23 (2015-12-10), S.13627-13632 |
| Datensatznummer |
250120215
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| Publikation (Nr.) |
 copernicus.org/acp-15-13627-2015.pdf |
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| Zusammenfassung |
| Photometric ozone measurements rely upon an accurate value of the
ozone absorption cross section at 253.65 nm. This has recently
been re-evaluated by Viallon
et al. (2015) as 1.8 % smaller than the
accepted value (Hearn, 1961) used for the preceding 50
years. Thus, ozone measurements that applied the older cross section
systematically underestimate the amount of ozone in air. We correct
the reported historical surface data from North America and Europe and
find that this modest change in cross section has a significant impact
on the number of locations that are out of compliance with air quality
regulations if the air quality standards remain the same. We find 18,
23, and 20 % increases in the number of sites that are out of
compliance with current US, Canadian, and European ozone air quality
health standards for the year 2012. Should the new cross-section
value be applied, it would impact attainment of air quality standards
and compliance with relevant clean air acts, unless the air quality
target values themselves were also changed proportionately. We draw
attention to how a small change in gas metrology has a global impact
on attainment and compliance with legal air quality standards. We
suggest that further laboratory work to evaluate the new cross section
is needed and suggest three possible technical and policy responses
should the new cross section be adopted. |
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