Air pollution in Bucharest, one of the worst in Europe, has a "serious impact" on the health of its inhabitants, Romanian environmental NGO Ecopolis warned on Wednesday.

"Bucharest is often and substantially above the threshold of polluting substances allowed in the air by the European Union and the World Health Organisation", Ecopolis said in a report analysing air pollution between 2004 and 2009 according to official data.

"This has a serious impact on the health of the population", it added.

According to Ecopolis, in 2009 alone more than 300 people suffering from chronic respiratory diseases could have avoided being treated in hospital if the level of fine particulate pollution had been reduced in the Romanian capital.

At the beginning of March, Bucharest came out as the worst pupil in the class in a EU-funded study on air pollution in 25 major European cities.

The nearly three-year probe, called Aphekom, found that Bucharest notched up 38.2 micrograms per cubic metre of fine particulate pollution when the UN's World Health Organisation (WHO) threshold is set at ten.

Life expectancy could be 22 months longer if air pollution was reduced, the study found.

Fine particulates are tiny airborne grains that can be drawn deep into the lungs, with the potential to cause respiratory and cardiovascular disease.

The pollution comes from traffic, especially diesel, exhausts, which means that it is particularly pronounced near major roads.

Ecopolis asked Romanian authorities and in particular Bucharest municipality to take "urgent measures" to reduce air pollution.

The president of the NGO, Costel Popa, criticized the mayor's project to build a large road through a historic district of Bucharest, saying it "will raise even more the number of cars" crossing the city.