Ireland's State of the Environment Report 2024

311 Chapter 12: Environment and Energy 2. Energy, health and the environment The generation of useful energy for mobility, heating and electricity through the combustion of coal, oil products, natural gas and peat (i.e. fossil fuels) releases polluting by-products that have significant adverse impacts on human health, the climate and our environment. Fossil fuel use is a significant source of key air pollutants and greenhouse gases (GHGs). The main impacts of combustion of fossil fuels include: ■ the emission of GHGs ■ the direct production of reactive gases such as nitrogen oxides, sulphur dioxide and particulates, including black carbon ■ the production of secondary pollutant gases and particulates such as ozone, ammonium nitrate and ammonium sulphate, and condensed compounds such as organic carbons ■ the release of heavy metals such as mercury and the formation of persistent organic pollutants such as polycyclic aromatic hydrocarbons, which build up in ecosystems and food chains. The relative impact on air quality and climate change depends on the fossil fuel used and its quality. The combustion of solid fuels such as coal and peat has the largest impacts, and gas combustion has the lowest impacts, with the combustion of liquid fuels typically having intermediate impacts (Figure 12.2). The combustion of biofuels can also result in significant air pollutant emissions that vary with fuel type and combustion systems used. Sustainably produced fuels such as wood, biogas and ethanol have less of an impact on the climate system but may have an impact on air quality. Figure 12.2  Energy use in 2022 and relative emissions of carbon dioxide, particulate matter and nitrogen oxides Non-renewable wastes 1.2% Natural gas 36.4% NO x PM CO 2 NO x PM CO 2 NO x PM CO 2 NO x PM CO 2 Solid fuels 8.0% Oil products 48.7% Non-renewable wastes Natural gas Solid fuels Oil products % share of national energy supplied 0% 10% 20% 30% 40% 50% 60% 70% 80% Sources: EPA, 2024a,b