Ireland's State of the Environment Report 2024

50 Chapter 2: Air Table 2.3  Number of national ambient air monitoring stations recording levels above WHO air quality guideline limits in 2023 Pollutant Number of stations where parameter was monitored in 2023 WHO Air Quality Guideline (AQG) level or EEA reference level a Particulate matter (PM 10 ) 106 Above annual WHO AQG value at 5 stations. Above daily WHO AQG value at 10 stations Fine particulate matter (PM 2.5 ) 101 Above annual WHO AQG value at 79 stations. Above daily WHO AQG value at 80 stations Nitrogen dioxide (NO 2 ) 36 Above annual WHO AQG value at 24 stations. Above daily WHO AQG value at 29 stations Ozone (O 3 ) 23 Above Peak Season WHO AQG level at 6 stations. Above 8hr av. daily WHO AQG value at 18 stations Sulphur dioxide (SO 2 ) 15 Above WHO 24 hour AQG level at 1 station a stations with at least 50% data capture Source: EPA, 2024b National Ecosystems Monitoring Network Excessive deposition of reactive nitrogen can have negative impacts on terrestrial ecosystems, including biodiversity loss, through eutrophication and acidification (Maskell et al. , 2010; Payne et al. , 2017). While deposited reactive nitrogen is principally composed of NH 3 and ammonium from agriculture, it also includes NO x . Even if Ireland succeeds in meeting its emission reduction commitments for NH 3 at a national level, high ambient NH 3 concentrations and deposited nitrogen are still likely to occur in certain locations. A goal of the European Commission’s Zero Pollution Action Plan is to reduce the size of the area of ecosystems at risk from nitrogen deposition by 25% by 2030. A recent report from the EEA highlighted that, while the size of the potentially affected area fell by 10% across Europe, it increased by 1% in Ireland in 2021 relative to 2005 (EEA, 2023c). This EEA report, modelling carried out on behalf of the EPA (Aherne et al. , 2021; Bealey et al. , 2024) and recent work measuring NH 3 at Natura 2000 sites (Kelleghan et al. , 2021) highlight that nitrogen deposition exceeds the level considered safe for many important sensitive habitats and species across Ireland. The NEC Directive requires every Member State to monitor the impacts of air pollution on sensitive ecosystems within its territory. Ireland’s response to this requirement has been to develop the National Ecosystems Monitoring Network (NEMN), which focuses on atmospheric NH 3 and other nitrogen-containing pollutants. The network is coordinated by the EPA and is reliant on input from various partners including the National Parks and Wildlife Service, Department of Agriculture, Food and the Marine and Met Éireann. The network consists of adapted botanical and forest surveys carried out by the National Parks and Wildlife Service and the Department of Agriculture, Food and the Marine across a variety of habitats including bogs, grasslands and woodlands (level 1 sites – see Figure 2.15a). These surveys are intended to determine any changes in the diversity of the plant communities in those habitats due to variations in atmospheric nitrogen deposition or NH 3 concentrations. The surveys are supplemented by atmospheric monitoring managed by the EPA on a smaller network of sites (level 2 sites – see Figure 2.15b), which are a subset of the level 1 network. Air quality monitoring for NH 3 is currently carried out at ten of these sites and it is anticipated that this will increase to approximately 19 sites by 2027.