Exceedance of the EU human health threshold value for ozone in urban areas
Assessment made on 01 Jan 2001
ClassificationAir pollution (Primary theme)
Policy issue: Are Europeans effectively protected against exposure to ground level ozone?
Ozone levels in Europe are exceeding the threshold set for protection of human health. Year-to-year fluctuations and changes in monitoring networks preclude firm conclusions on trends in population exposure; analysis of monitoring data suggests that peak ozone concentrations are decreasing, but median values are tending to increase.
Part of this fluctuation is natural, as the production of ground level ozone partly depends on special weather conditions that vary from year to year. The data is also not completely consistent, particularly before 1994, due to changes in the monitoring networks.
Despite the fluctuations, it is clear that the current limits are exceeded frequently for a large proportion of the EU's population. Estimates for 1999, for example, suggest that 42% of the population was overexposed on 1-25 days, with 12% overexposed for more than 50 days. Only the Northern European countries and Portugal had less more than 10 exceedance days. Although emissions of the substances that lead to ground level ozone are dropping (see ozone precursors), the reductions are unlikely to help meet either today's or tomorrow's targets, with north-west Europe expected to experience around 25 exceedance days per year by 2010.
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Exceedance days of air quality threshold value of Nitrogen Dioxide
Exceedance days of air quality threshold values for ozone in urban areas
Policy Update Air Pollution