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| Titel |
Scorched Earth: how will changes in the strength of the vegetation sink to ozone deposition affect human health and ecosystems? |
| VerfasserIn |
L. D. Emberson, N. Kitwiroon, S. Beevers, P. Büker, S. Cinderby |
| 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 ; 13, no. 14 ; Nr. 13, no. 14 (2013-07-18), S.6741-6755 |
| Datensatznummer |
250018764
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| Publikation (Nr.) |
 copernicus.org/acp-13-6741-2013.pdf |
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| Zusammenfassung |
| This study investigates the effect of ozone (O3) deposition on ground
level O3 concentrations and subsequent human health and ecosystem risk
under hot summer "heat wave" type meteorological events. Under such
conditions, extended drought can effectively "turn off" the O3
vegetation sink leading to a substantial increase in ground level O3
concentrations. Two models that have been used for human health (the CMAQ
chemical transport model) and ecosystem (the DO3SE O3 deposition
model) risk assessment are combined to provide a powerful policy tool
capable of novel integrated assessments of O3 risk using methods
endorsed by the UNECE Convention on Long-Range Transboundary Air Pollution.
This study investigates 2006, a particularly hot and dry year during which a
heat wave occurred over the summer across much of the UK and Europe. To
understand the influence of variable O3 dry deposition three different
simulations were investigated during June and July: (i) actual conditions in
2006, (ii) conditions that assume a perfect vegetation sink for O3
deposition and (iii) conditions that assume an extended drought period that
reduces the vegetation sink to a minimum. The risks of O3 to human
health, assessed by estimating the number of days during which running 8 h
mean O3 concentrations exceeded 100 μg m−3, show that on average
across the UK, there is a difference of 16 days exceedance of the threshold
between the perfect sink and drought conditions. These average results hide
local variation with exceedances between these two scenarios reaching as
high as 20 days in the East Midlands and eastern UK. Estimates of acute
exposure effects show that O3 removed from the atmosphere through dry
deposition during the June and July period would have been responsible for
approximately 460 premature deaths. Conversely, reduced O3 dry
deposition will decrease the amount of O3 taken up by vegetation and,
according to flux-based assessments of vegetation damage, will lead to a
reduction in the impact of O3 on vegetation across the UK. The new
CMAQ-DO3SE model was evaluated by comparing observation vs. modelled
estimates of various health related metrics with data from both urban and
rural sites across the UK; although these comparisons showed reasonable
agreement there were some biases in the model predictions with attributable
deaths at urban sites being over predicted by a small margin, the converse
was true for rural sites. The study emphasises the importance of accurate
estimates of O3 deposition both for human health and ecosystem risk
assessments. Extended periods of drought and heat wave type conditions are
likely to occur with more frequency in coming decades, therefore
understanding the importance of these effects will be crucial to inform the
development of appropriate national and international policy to mitigate
against the worst consequences of this air pollutant. |
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