About the data

Last modified: Mar 14, 2011

Data from more than 700 air quality measurement stations across Europe are transmitted to the EEA in Copenhagen on an hourly basis. Since the data must be as 'real-time' as possible, the data are displayed as soon as practical after the end of each hour.

The air quality data used in the website are preliminary. The data may change when they are validated hence they are not used for legal compliance reporting. Use restrictions on some data may apply (see data providers websites below for more information).

In the map, the ozone level is illustrated by colours. The colour scheme is linked to threshold values in EU legislation. To provide an estimate of the ozone status in areas between measurement stations, a statistical calculation (interpolation) is carried out on the ozone data received by the EEA. Before the result of the calculation is shown on the map, a number of conditions have to be satisfied by the input data and the resulting calculation. These conditions are:

The number of stations is greater than 500 and data is received from more than 80 % of the providers.
The density pattern of stations from which data is received is not significantly different from what is normally expected.
The root mean squared error value (RMSE) from a cross validation test carried out between data from 10 % of the data received against the result of the interpolation calculation is less than 20 µg/m³.

Background data providers

Provider	Data sets	Link
© Tele Atlas 2004	Derived data based on generalisations of streets, built-up areas, administrative areas, centre of settlements, ocean/sea, water area, water line	http://www.teleatlas.com/Pub/Home
© EuroGeographics	EuroGlobalMap v1.1 (Transportation)	http://www.eurogeographics.org/eng/04_products_globalmap.asp
ArcWorld Supplement, Environmental Systems Research Institute (ESRI)	Countries 2002	http://www.esri.com/index.html
© EEA, Copenhagen, 2005	Corine land cover 2000 forests, Corine land cover 2000 lakes	http://dataservice.eea.eu.int/dataservice
Eurostat, Luxembourg	European settlements	http://epp.eurostat.cec.eu.int/
This product was developed using materials from the United States National Imagery and Mapping Agency and are reproduced with permission. This product has neither been endorsed nor authorized by the United States National Imagery and Mapping Agency or the United States Department of Defense.	Vmap0 (road, built-up area, political boundary, water area, inland water, water course)	http://www.mapability.com/index1.html?http&&&www.mapability.com/info/vmap0_index.html
Toponymic information is based on the Geographic Names Data Base, containing official standard names approved by the United States Board on Geographic Names and maintained by the National Geospatial-Intelligence Agency. More information is available at the Products and Services link at www.nga.mil.	GEOnet Names Server (GNS)	http://earth-info.nga.mil/gns/html/index.html