1,000 Dublin citizen scientists measure pollution from traffic

Date released: March 10, 2022

  • The Clear Air Together Citizen Science Project, led by the EPA and the Environmental Education Unit of An Taisce, has worked with 1000 Dublin citizen scientists to measure air pollution from traffic in their local areas.
  • The results clearly show that higher nitrogen dioxide levels are linked with higher traffic volumes.
  • The results will be used by the EPA to to support air quality modelling in Dublin and will be used by Dublin local authorities to support air quality management.
  • None of the results indicate a breach of EU air quality limit (40 µg/m3).
  • Clean Air Together is moving to Cork in late 2022.

10 March 2021: The Environmental Protection Agency (EPA) and An Taisce’s Environmental Education Unit this evening hosted a webinar with the citizen scientists of the Clean Air Together project, to present the results of the study. During October 2021, these citizen scientists measured levels of the harmful air pollutant, Nitrogen Dioxide (NO2). The information gathered by them will now be used by the EPA to assist with air quality modelling and forecasting.

Commenting on the project, Andy Fanning, Programme Manager in EPA, said:

“Clean Air Together is a real success story for Citizen Science, with almost one thousand residents in Dublin measuring the levels of air pollution in their local areas. While the EPA has fixed air pollution monitoring sites in Dublin, this project has given us data about many areas that we are currently unable to monitor. This is the first time such a study has been run in Ireland and we are thrilled to see the level of interest. Unfortunately, we had to turn some people away and very much hope we can find ways to work with them again in the future. We simply couldn’t have completed this project without Dublin’s citizen scientists”.

Results showed that, while NO2 levels across Dublin city and county were generally good, higher levels were found near busy roads. This is not unexpected, as NO2 comes mainly from traffic. None of the levels reported in this project exceeded the EU annual average limit (40 µg/m3) but it should be noted that lower levels of NO2, are better for everyone’s health. All results are available on the Clean Air Together project site.

Sabrina Moore, Clean Air Together project manager An Taisce’s Environmental Education Unit added:

“The level of interest in this project shows people’s growing awareness of the importance of good air quality in their city, and a genuine interest in helping to protect their environment. So, what can we all do for our air quality? Where possible we should try to limit our personal car use by using public transport more often, or by walking or cycling. Continued investments in these infrastructures will make these choices easier. By shifting our behaviour we can make a difference and ensure that air quality is healthier across the city”.

Further information: Emily Williamson, EPA Media Relations Office 053-9170770 (24 hours) or media@epa.ie

Notes to Editor

Summary of results

The results show the impact of traffic on Nitrogen Dioxide (NO2) air pollution levels: higher NO2 levels are linked with higher traffic volumes. All results are available on the Clean Air Together project site.

On the map, higher NO2 results are represented as orange dots and yellow dots - mostly present in the city centre (within the canals) and along some of the major roads in Dublin city. Moving outwards to the suburbs and away from major roads, the lower levels of NO2 (light blue) are found. Most of the lowest results (dark blue dots) can be found further away on the outer suburbs of Dublin, sea-side towns and countryside of Dublin county.


Image of map of coloured dots showing results of Clean Air Together (Dublin)
Image of map of coloured dots showing results of Clean Air Together (Dublin)


The results fall into the following categories:

  • Orange dots (30 μg/m3 – 40 μg/m3) represent 2% of the measurements.
  • Yellow dots (20 μg/m3 – 30 μg/m3) represent 12% of the measurements.
  • Light blue dots (10 μg/m3 – 20 μg/m3) represent 66% of the measurements.
  • Dark blue dots (0 μg/m3 – 10 μg/m3) represent 20% of the measurements

Air Quality Monitoring

The EPA continually monitors air quality across Ireland and provides the Air Quality Index for Health (AQIH) and real-time results online at www.airquality.ie. Results are updated hourly, and people can log on at any time to check whether the current air quality is good, fair or poor.
Clean Air Together is a partnership project between the Environmental Protection Agency (EPA) and Environmental Education Unit of An Taisce. Details of the project are available at www.cleanairtogether.ie and the EPA website.

Air quality is assessed through the National Ambient Air Quality Monitoring Programme. The programme comprises the EPA, working with local authorities and other public bodies, has established 97 air monitoring stations, 18 of which were installed in 2020 and 13 measure NO2 levels across Dublin. Monitoring data from these stations is available in real time on the website www.airquality.ie and the data is used to inform national policy and meet Irelands commitments to European reporting.

What is Nitrogen Dioxide?

Nitrogen dioxide (NO2) is a gas emitted by traffic and is the main pollutant of concern from traffic pollution. NO2 is linked to airway inflammation in healthy people and increased respiratory symptoms in asthmatics. Over the long term, NO2 exposure is linked to increased risk of respiratory infection in children.

Comprehensive information on NO2 and air quality is available at www.airquality.ie

How was Nitrogen Dioxide measured in the Clean Air Together project?

Nitrogen Dioxide is measured using a measurement tube called a diffusion tube, which is a small plastic tube about the size of a lip stick tube. The bottom white cap of the tube is removed to let air pass through during the measurement period. A special substance is contained in the upper grey cap that can absorb NO2. The small tube is placed on the outside of window of the participant’s properties and left in place for a four-week period. Once the measurement period is over, air sampling is stopped by closing off the tube with the white cap and the tube then returned by post for lab analysis.

What is being done to address NO2 in Dublin?

Dublin’s Air Quality Action Plan (2021), sets out 14 broad measures and a number of associated actions to address the exceedance of the nitrogen dioxide annual limit value in 2019 at St John’s Road West, Inchicore located near Heuston station.

Further information is available at: