Road traffic volumes in urban areas - especially in Dublin - will make it difficult for Ireland to meet new EU standards on air pollution. This is in spite of considerable success in curbing discharges of noxious pollutants such as lead and sulphur dioxide, according to the Environmental Protection Agency.
In its first annual report on the results of Irish air quality monitoring, for 1996, it finds that the EU's proposed standards for dust and nitrogen dioxide "may be difficult to achieve in parts of Dublin."
Cars and other motor vehicles remain the greatest culprit. The warning comes after results indicate that a greater use of unleaded petrol has resulted in ambient lead concentrations in air decreasing "to very acceptable levels".
Equally, air pollution associated with coal burning from the residential sector, which represented a threat to urban air in Dublin prior to 1990, has been dramatically reduced by switching to cleaner fuels and the application of smoke-control legislation.
When measures to reduce nitrogen oxides in power stations and increasing restraint under integrated pollution control licensing are taken into account, "this leaves road traffic as the greatest threat to the quality of air, especially in the urban environment."
Dust is of concern because of its direct impact on human health, notably through asthmas, which are increasingly debilitating to children. Nitrogen oxides emitted into the atmosphere not only affect human health but also contribute to acidification, increased levels of tropospheric ozone and damage to ecosystems and materials.
Levels of nitrogen dioxide in the air at kerbside locations subject to heavy traffic, such as Dublin's College Street, regularly approach current limit values and "could easily go over this level given unfavourable weather conditions" - such as when temperature inversions (cold air sitting on warm air) occur in winter and pollutants cannot disperse. Such conditions can give rise to smog.
The EPA recommends more extensive monitoring of this pollutant in Dublin, both because of the levels occurring and of discrepancies in levels found in monitoring stations.
The report shows that:
For most pollutants, levels found are "well within current Irish quality standards and EU limits on air quality", notwithstanding some concern about the levels of benzene associated with road traffic.
Carbon monoxide levels found in Dublin were well within World Health Organisation guidelines - breaches in many European mainland cities are frequent.
During 1996, the EPA commenced monitoring of "volatile organic compounds", regarded as among the worst forms of modern pollutants. The focus was on benzene, toluene and three xylenes along traffic routes. The report says benzene monitoring should be increased.
Ozone levels were very low, but this is to be expected because of prevalent weather systems in Ireland and relative absence of "precursor emissions" which can lead to ozone.
The EPA is developing a new national air monitoring programme and improving monitoring systems to "reflect changes taking place in air pollution problems, with particular emphasis on traffic-related problems".
