Air pollution by ozone

Indicator Specification
Indicator codes: CLIM 006
Created 11 Jul 2008 Published 08 Sep 2008 Last modified 04 Sep 2015
5 min read
Modelled change in tropospheric ozone concentrations over Europe 1958-2001 and 1978-2001 Change in number of ozone exceedance days between 1993-1996 and 2000-2004 Contribution of temperature increase to the change in ozone exceedance days between 1993-1996 and 2000-2004

Assessment versions

Published (reviewed and quality assured)


Justification for indicator selection

Tropospheric ozone is one of the air pollutants of most concern in Europe. Ozone is estimated to cause about 20 000 acute mortalities each year (European Commission, Clean Air for Europe impact assessment, 2006) and economic damage due to crop loss of EUR 4 625 million per year (Holland et al., 2006). Ozone is formed in the lower troposphere as a result of complex chemical reactions between volatile organic compounds and nitrogen oxides, in the presence of sunlight. EU legislation has established ozone exceedance thresholds and national emission ceilings for ozone precursor emissions to protect human health and prevent damage to ecosystems, agricultural crops and materials.
Episodes of elevated ozone levels occur mainly during periods of warm sunny weather (Schichtel and Husar, 2001; Rao et al., 2003). The projected increase in hot extremes in Europe is therefore expected to result in ozone episodes that require more vigorous emission reduction measures and the use of the available adaptation measures such as improved public information and health care services.

Scientific references

  • References Andersson, C.; Langner, J. and Bergström, R., 2007. Interannual variationand trends in air pollution over Europe due to Climate variability during 1958-2001 simulated with a regional CTM coupled to the ERA40 reanalysis, Tellus 59B: 77-98. Fiala, J.; Cernikovsky, L.; de Leeuw, F.; Kurfuerst, P., 2003. Air pollution by ozone in Europe in summer 2003, EEA Topic report No. 3/2003. Hogrefe, C.; Biswas, J.; Lynn, B.; Civerolo, K.; Ku, J. Y.; Rosenthal, J.; Rosenzweig, C.; Goldberg, R. and Kinney, P. L., 2004. Simulating regional-scale ozone climatology over the eastern United States: model evaluation results. Atmospheric Environment 38 (17): 2627-2638. Holland, M.; Kinghorn, S.; Emberson, L.; Cinderby, S.; Ashmore, M.; Mills, G. and Harmens, H., 2006. Development of a framework for probabilistic assessment of the economic losses caused by ozone damage to crops in Europe, CEH project No. C02309NEW. Centre for Ecology and Hydrology, Natural Environment Research Council, Bangor, Wales, 49 pp. Meleux, F.; Solmon, F. and Giorgi, F., 2007. Increase in summer European ozone amounts due to climate change. Atmospheric Environment, 41, 7577-7587: 10.1016/ j.atmosenv.2007.05.048. OECD, 2008. Environmental outlook to 2030. OECD Publishing, . Rao, S. T.; Ku, J. Y.; Berman, S.; Zhang, D. and Mao, H., 2003. Summertime characteristics of the atmospheric boundary layer and relationships to ozone levels over the eastern United States. Pure and Applied Geophysics 160: 21-55. Schichtel, B. A. and Husar, R. B., 2001. Eastern North American transport climatology during high- and  low-ozone days. Atmospheric Environment 35: 1029-1038. Sousounis P. J.; Scott, C. P. J. and Wilson. M. L., 2002. Possible climate change impacts on ozone in the Great Lakes region: Some implications for respiratory illness. Journal Of Great Lakes Research 28 (4): 626- 642. Stevenson, D. S.; Dentener, F. J.; Schultz, M. G.; Ellingsen, K.; van Noije, T. C. P.; Wild, O.; Zeng, G.; Amann, A.; Atherton, C. A.; Bell, N.; Bergmann, D. J.; Bey, I.; Butler, T.; Cofala, J.; Collins, W. J.; Derwent, R. G.; Doherty, R. M.; Drevet, J.; Eskes, H. J.; Fiore, A. M.; Gauss, M.; Hauglustaine, D. A.; Horowitz, L. W.; Isaksen, I. S. A.; Krol, M. C.; Lamarque, J.-F.; Lawrence, M. G.; Montanaro, V.; Müller, J.-F.; Pitari, G.; Prather, M. J.; Pyle, J. A.; Rast, S.; Rodriguez, J. M.; Sanderson, M. G.; Savage, N. H.; Shindell, D. T.; Strahan, S. E.; Sudo, K. and Szopa, S., 2006. Multimodel ensemble simulations of present-day and near-future tropospheric ozone. Journal of Geophysical Research 111, D08301,  DOI:10.1029/2005JD006338. Van Dingenen, R.; Raes, F.; Dentener, F.; Putaud, J. P.  and Micale, F., 2008. The relation between temperature anomaly and ozone exceedance as an indication for the role of climate change on ozone exceedance in Europe (manuscript in preparation).

Indicator definition

  • Modelled change in tropospheric ozone concentrations over Europe 1958-2001 and 1978-2001
  • Change in number of ozone exceedance days between 1993-1996 and 2000-2004
  • Contribution of temperature increase to the change in ozone exceedance days between 1993-1996 and 2000-2004


Policy context and targets

Context description

In April 2009 the European Commission presented a White Paper on the framework for adaptation policies and measures to reduce the European Union's vulnerability to the impacts of climate change. The aim is to increase the resilience to climate change of health, property and the productive functions of land, inter alia by improving the management of water resources and ecosystems. More knowledge is needed on climate impact and vulnerability but a considerable amount of information and research already exists which can be shared better through a proposed Clearing House Mechanism. The White Paper stresses the need to mainstream adaptation into existing and new EU policies. A number of Member States have already taken action and several have prepared national adaptation plans. The EU is also developing actions to enhance and finance adaptation in developing countries as part of a new post-2012 global climate agreement expected in Copenhagen (Dec. 2009). For more information see:


No targets have been specified

Related policy documents

No related policy documents have been specified

Key policy question



Methodology for indicator calculation

Methodology for gap filling

Methodology references

No methodology references available.

Data specifications

EEA data references

External data references

Data sources in latest figures


Methodology uncertainty

Data sets uncertainty

Rationale uncertainty

No uncertainty has been specified

Further work

Short term work

Work specified here requires to be completed within 1 year from now.

Long term work

Work specified here will require more than 1 year (from now) to be completed.

General metadata

Responsibility and ownership

EEA Contact Info

John Van Aardenne


Joint Research Centre (JRC)
European Environment Agency (EEA)


Indicator code
CLIM 006
Version id: 1
Primary theme: Air pollution Air pollution


DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
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