Emissions from motor vehicles are now the biggest threat to Dublin's air quality according to a report for the region.

The proposed Air Quality Management Plan found that emissions of Nitrogen Dioxide and Particulate Matter in Dublin are in danger of breaching safety guidelines.

The study found that the benefits of fuel improvements such as the introduction of lead-free petrol have been offset by the doubling of car users in Ireland between 1990 and 2006.

The report for the four Dublin local authorities said a switch to public transport, measures to ease traffic congestion and the promotion of fuel efficient cars will help air pollution within limits.

It found that the highest readings in the country for Particulate Matter emissions in 2007 were outside the capital - in Ennis, Waterford and Navan.

The study found that overall the Dublin area's air quality is good compared to other European cities and has improved dramatically over the years.

It also found that the ban on bituminous coal burning in Dublin had saved an estimated 359 lives every year for the past 19 years.

However, it found that 'backyard burning' continues to be a problem causing 50% of the country's dioxin emissions.

It quoted results of an EPA survey that found 15% of Irish adults believed backyard burning is acceptable and that half of those that did it were aware of the public health implications.