Air pollution is continuing to damage European citizens' health and the environment, latest figures show.
The European Environment Agency (EEA) listed tiny airborne particles and ozone as posing a "significant threat".
However, the authors said nations had significantly cut emissions of a number of pollutants, including sulphur dioxide, lead and carbon monoxide.
In a separate study, research identified a link between low birth-weight and exposure to air pollution.
EEA executive director Hans Bruyninckx said that EU nations had made considerable progress over recent decades to reduce the visible signs of air pollution, with cities now no longer shrouded in blankets of smog.