Ireland's State of the Environment Report 2024

39 Chapter 2: Air WHO stresses that even extremely low levels of air pollution can have health impacts, such that there is no safe level of air pollution. Therefore, taking action even at low levels of pollution can deliver health benefits. The pollutants of concern in Ireland are fine particulate matter, nitrogen dioxide and ammonia (Table 2.1). Table 2.1  Fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ) and ammonia (NH 3 ) Pollutant Description Sources and solutions Fine particulate matter Particulate matter is a mixture of very small solid and liquid particles suspended in air. PM 2.5 particles have a diameter of < 2.5 µm. Small particles can penetrate the lungs and enter the blood system, causing damage. PM 2.5 is a strong indicator of anthropogenic (human-generated) emissions and it is responsible for significant negative impacts on human health. Levels of PM 2.5 are particularly problematic in or near urban centres, villages, towns and cities, because of the cumulative effects of multiple sources of the pollutant, with the dominant source being solid fuels used in home heating. PM 2.5 pollution can be reduced by changing how we heat our homes, specifically by moving away from smoky fuels and choosing cleaner options. Nitrogen dioxide While not as impactful on health as PM 2.5 , NO 2 can have negative impacts on respiratory and cardiovascular health. Nitrogen oxides (NO x ) also contribute to the acidification of soils and surface waters, and to ground level ozone (O 3 ) formation. They can contribute to excess nitrogen in terrestrial ecosystems. The dominant sources of NO 2 are from transport, particularly diesel- and petrol-powered vehicles. NO 2 pollution is particularly an issue in urban areas due to transport emissions. NO 2 pollution could be decreased by reducing overall traffic volumes in towns and cities, increasing the electrification of the fleet and giving consideration to low emission zones in our largest urban centres. Ammonia NH 3 emissions to air are associated with nitrogen deposition, acid rain and the formation of secondary particulate matter. Excessive deposition of reactive nitrogen negatively affects terrestrial ecosystems, including biodiversity loss, through eutrophication and acidification. Agriculture is the dominant source of NH 3 emissions in Ireland. To decrease concentrations, there is an urgent need for a significant uptake of abatement techniques such as low-emission slurry spreading, the use of inhibited fertiliser products and reduction in the crude protein concentration of livestock feeds.