Marked long-term decline in ambient CO mixing ratio in SE England, 1997–2014:Evidence of policy success in improving air quality

Lowry, D., Lanoisellé, M. E., Fisher, R. E., Martin, M., Fowler, C. M. R., France, J. L., Hernández-Paniagua, I. Y., Novelli, P. C., Sriskantharajah, S., O’Brien, P., Rata, N. D., Holmes, C. W., Fleming, Z. L., Clemitshaw, K. C., Zazzeri, G., Pommier, M., McLinden, C. A. and Nisbet, E. G. (2016) Marked long-term decline in ambient CO mixing ratio in SE England, 1997–2014:Evidence of policy success in improving air quality. Scientific Reports, 6. ISSN 2045-2322

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Abstract

Atmospheric CO at Egham in SE England has shown a marked and progressive decline since 1997, following adoption of strict controls on emissions. The Egham site is uniquely positioned to allow both assessment and comparison of ‘clean Atlantic background’ air and CO-enriched air downwind from the London conurbation. The decline is strongest (approximately 50ppb per year) in the 1997–2003 period but continues post 2003. A ‘local CO increment’ can be identified as the residual after subtraction of contemporary background Atlantic CO mixing ratios from measured values at Egham. This increment, which is primarily from regional sources (during anticyclonic or northerly winds) or from the European continent (with easterly air mass origins), has significant seasonality, but overall has declined steadily since 1997. On many days of the year CO measured at Egham is now not far above Atlantic background levels measured at Mace Head (Ireland). The results are consistent with MOPITT satellite observations and ‘bottom-up’ inventory results. Comparison with urban and regional background CO mixing ratios in Hong Kong demonstrates the importance of regional, as opposed to local reduction of CO emission. The Egham record implies that controls on emissions subsequent to legislation have been extremely successful in the UK.

Item Type: Article
Additional Information: This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: Pure Connector
Date Deposited: 02 Jun 2016 16:01
Last Modified: 20 May 2020 23:59
URI: https://ueaeprints.uea.ac.uk/id/eprint/59203
DOI: 10.1038/srep25661

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