Percentage of population resident in urban areas potentially exposed to SO2 concentration levels exceeding the daily limit value, EEA member countries, 1997-2007
The limit value is 125 µg SO2/m3 as a daily mean, not to be exceeded more than three days in a year. Over the years 1997-2007 the total population for which exposure estimates are made, increases from 56 to 101 million people due to an increasing number of monitoring stations reporting under the Exchange of Information Decision. 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.