EPA - Ireland's Environment, An Integrated Assessment - 2020

Ireland’s Environment – An Integrated Assessment 2020 Figure 3.10 Modelled annual average nitrogen dioxide concentrations in Dublin for 2017 Topic Box 3.3 Modelling Air Quality in Dublin In 2019, the EPA released a report entitled Urban Environmental Indicators: Nitrogen Dioxide Levels in Dublin , which detailed modelled concentrations of nitrogen dioxide beyond monitoring stations (EPA, 2019a). The report found that based on air quality indicative monitoring and modelling predictions many areas across Dublin, in particular those close to busy roads, were above the EU nitrogen dioxide annual limit value of 40 μg/m 3 . The modelled concentrations of nitrogen dioxide were highest around the M50 motorway, along certain city centre streets, and around the entrance and exit of the Dublin Port tunnel. Away from busy roads, the modelling showed that levels of nitrogen dioxide are low. The modelled predictions have since been used, along with indicative measurements, to aid the siting of new monitoring stations such as those at the Pearse Street and St John’s Road West sites. Figure 3.10 shows the modelled annual average nitrogen dioxide levels across Dublin. Nitrogen Dioxide Diffusion Tube Results in Other Cities Since 2017, the EPA, in partnership with local authorities in Dublin, Cork, Limerick, Galway and Waterford, has been monitoring indicative nitrogen dioxide levels using passive diffusion tubes. Diffusion tubes allow measurements to be obtained at additional locations beyond the permanent monitoring network. Figure 3.11 shows the indicative annual nitrogen dioxide levels from diffusion tubes around Limerick City. These studies have enabled areas of high nitrogen dioxide concentrations, associated with heavily trafficked roads, to be identified. Information for other cities and years are available on the EPA website at www.airquality.ie. The air quality situation in 2020 has changed significantly as a result of restrictions on people’s movement in response to the coronavirus (COVID-19) pandemic, especially during the period of ‘full lockdown’. There is clear evidence that there was a decrease in air pollution, particularly towards the end of March and beginning of April 2020, which coincided with the introduction of restrictions on movement. The EPA has been assessing monthly concentrations of nitrogen dioxide and comparing them with the corresponding period in previous years. Owing to a strong association with road transport, nitrogen dioxide levels have been affected to the greatest extent, with decreases of up to 50 per cent compared with previous years. The largest decreases were observed at urban traffic monitoring stations in the National Ambient Air Quality Monitoring Network. 74