Heavy road traffic has become the single biggest threat to air quality in Ireland, with proposed new EU limits already being exceeded in parts of Dublin, according to the Environmental Protection Agency.
In its annual report on air quality monitoring for last year, the EPA confirms that fine particulate matter - a noxious, traffic-related pollutant - is exceeding levels likely to be set as EU limits at College Street and Wood Quay in Dublin. Nitrogen oxides - pollutants emitted by cars and other vehicles - were also "well in excess of guideline values".
The report notes that the number of monitoring stations is "relatively small" and "insufficient" .
"Stringent new limit values for fine particulate matter (PM10), sulphur dioxide, nitrogen dioxide and lead will have to be reached within the next 10 to 15 years," the report warns. New laws will need to ensure considerable resources for extending monitoring networks and using more sophisticated measuring devices and reporting systems.
Traffic volumes confirm that it will be hard to comply with the new EU limits, the report's author, senior scientific officer, Mr Michael McGettigan, said. Ireland would also have to submit plans on reducing air pollutant levels. With PM10 and nitrous oxides, it would mean reducing traffic volumes where limits were being exceeded. "There is no other way," he added.
PM10 are fine particles that can travel deep into the lungs and cause respiratory disease including asthma and cancer. They are emitted from exhausts, particularly in diesel fumes but also from brake and tyre wear. Traffic can "re-suspend" particles on the ground. Their threat may be compounded when other pollutants, such as aerosols and metals, attach to them.
At two Dublin city centre sites (College Green and Wood Quay) the annual mean PM10 level was marginally over 40 micrograms/m3 , and daily values exceeded - by a considerable margin - 50 mircograms/m3 on approximately 25 per cent of days for which measurements were available. Both figures are proposed new limits.
The EPA report confirms that concentrations of smoke and sulphur dioxide are now at very low levels, fully complying with Irish standards and EU directives. Concentrations of carbon monoxide, often associated with road traffic, were found to be well within World Health Organisation guidelines though there are very little monitoring data available.
