Percentage of population resident in urban areas potentially exposed to O3 concentration levels over the long-term objective for protection of human health, EEA member countries, 1997-2007
The target value is 120 µg O3/m3 as daily maximum of 8 hour mean, not to be exceeded more than 25 days per calendar year, averaged over three years. Over the years 1997-2006 the total population for which exposure estimates are made, increases from 48 to 112 million people due to an increasing number of monitoring stations reporting under the Exchange of Information Decision. Data prior to 1996 with a coverage of less than 50 million people are not representative for the European situation. Year-to-year variations in exposure classes are partly caused by the changes in spatial coverage. Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus, Iceland, Liechtenstein, Luxembourg, Malta, Norway and Turkey are not included due to the geographical coverage of the Urban Audit and/or lack of air quality data.