Hundreds of Cork City citizen scientists measure air pollution from traffic. Clean Air Together Cork City – The Results!

Date released: February 22, 2023

  • The Clean Air Together Citizen Science Project worked with over 700 citizen scientists in Cork city to measure air pollution from traffic in their local areas.  
  • The results show that higher nitrogen dioxide levels are linked with higher traffic volumes. 
  • While none of the results indicate a breach of the current EU air quality limit (40 µg/m3) there is no safe level of air pollution. Making good choices can reduce levels of air pollution in our environment. 
  • The results will be used by the EPA to help model air quality in Cork City and will also  be used by Cork City Council to support the implementation of the Council’s 2021-2026 Air Quality Strategy.

22 February 2023:  In October 2022, more than 700 citizen scientists measured levels of the harmful air pollutant, Nitrogen Dioxide (NO2) in Cork City as part of the Clean Air Together (Cork City) project. A public event will be hosted in Cork City Hall this evening at 5pm to present the results of the study to them. The project was led by the Environmental Protection Agency (EPA) and An Taisce’s Environmental Education Unit, who worked with Cork City Council to deliver this large-scale project.  

The information gathered will now be used by the EPA to assist with air quality modelling and forecasting, and by Cork City Council to support the implementation of the Council’s 2021-2026 Air Quality Strategy.  

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

“Clean Air Together Cork is a great success story, with over 700 Citizen Scientists in the City measuring the levels of traffic pollution in their local areas.  While the EPA already has fixed monitoring sites in the city, this project has given us data about many areas that we are currently unable to monitor.  We simply couldn’t have completed this project without Cork City’s citizen scientists, and it is wonderful to see the commitment of the people of Cork City to their local environment”.

Nitrogen Dioxide levels across Cork City were generally low and none of the results found levels above the EU annual average limit (40 µg/m3).   Some higher levels were found near busy roads and in the city centre, which is expected as NO2 comes mainly from traffic. Lower levels of Nitrogen Dioxide are better for everyone’s health as there is no safe level of air pollution.  All results from the project are available on the Clean Air Together project site

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

“The 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.  We can all make a difference, in our everyday lives, to ensure that air quality is healthier across the city.  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 sustainable choices easier”.

Further information: Emily Williamson, EPA Media Relations Office 053-9170770 (24 hours) or
Photos from the live event on Wednesday 22nd will be available from the EPA Media Relations Office also.

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.

Map of Cork City Clean Air Together results


On the map, higher NO2 results are represented as orange dots and yellow dots - mostly present in the city centre and along some of the major roads in Cork 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 Cork City.

The results fall into the following categories:

  • Orange dots (30 μg/m3 – 40 μg/m3) represent 1% of the measurements.
  • Yellow dots (20 μg/m3 – 30 μg/m3) represent 6% of the measurements.
  • Light blue dots (10 μg/m3 – 20 μg/m3) represent 35% of the measurements.
  • Dark blue dots (0 μg/m3 – 10 μg/m3) represent 58% of the measurements

At 6 out of 10 locations sampled, NO2 levels fall into the lowest category.  As expected, this includes locations in the countryside and in less trafficked parts of Cork city.  Most other locations are in the next category up (10-20 µg/m3).  In total, the (0-20 µg/m3) category accounted for 93% of the study’s results (light blue and dark blue dots).  7% of the results are above 20 µg/m3.  The highest NO2 levels were found by national roads: 

  • Lower Glanmire road and MacCurtain street (N8)
  • Commons Road, Leitrim Street and Carroll’s Quay (N20)
  • South Link Road (N27).

The Cork campaign follows a similar and successful campaign in Dublin in 2021. A third campaign is being planned in Galway City for later in 2023. 

Air Quality Monitoring

The EPA continually monitors air quality across Ireland and provides the Air Quality Index for Health and real-time results online at  Results are updated hourly, and people can check at any time whether the current air quality is good, fair, or poor.

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 110 air monitoring stations, and 5 of which are in Cork City.  Monitoring data from these stations is available in real time on the website and the data is used to inform national policy and meet Irelands commitments to European reporting.

The results of Clean Air Together (Cork City) are an indication of the level of NO2 measured at particular locations in Cork City in October 2022.  NO2 levels can vary considerably over the year with changing traffic volumes and weather conditions.  Therefore, the results should be viewed as a “snapshot”, representative of the NO2 levels in October 2022 and not a definitive measurement of NO2. 

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.

The results of Clean Air Together Cork indicate that EU legal limit for NO2 was not exceeded.  However, these month long results also suggest that in some cases the new health-based Annual Average guideline for Nitrogen Dioxide from the WHO of 10 µg/m3 may not have been met.  It is the EPA’s view that Ireland and Europe should move towards achieving the health-based WHO air quality guidelines over time.  

Comprehensive information on NO2, air quality and the air quality standards for Ireland is available at

How was Nitrogen Dioxide measured in the Clean Air Together project? [See demonstration video here: How to install your tube - Clean Air Together Cork City - YouTube.]

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 is then returned by post for lab analysis.

What is being done to address NO2 in Cork City? 

Cork City Council adopted their Clean Air Strategy in 2021 while at a national level the Climate Action Plan (2021), and the New National Investment Framework for Transport in Ireland (2021) have been adopted which all comprise of actions that will help reduce levels of NO2 across the country. These actions include among many:

  • Building more and safer cycle lanes and footpaths.
  • Investing in clean public transport and exploring the development of low emission zones. There are now multiple hybrid buses running in many towns / cities.
  • Planning to apply the 15-minute city development concept more frequently. A 15-minute city is a neighbourhood in which you can access your day-to-day needs within a 15-minute walk of your home (think schools, access to health professionals, groceries, etc.). 
  • Building more electric-vehicle (EV) charging stations and making it more accessible to purchase an EV as your next vehicle purchase.
  • In April 2022, Cork City Council launched Ireland’s first Clean Air Zone. The area encompasses Oliver Plunkett Street and adjacent streets (part of the main shopping and commercial areas in the city) and involves restricting vehicle access to the area other than deliveries (morning and evening) and creates a pedestrian priority zone. Other such pedestrian priority zones exist at Rory Gallagher Square and adjacent streets.
  • As part of proof of concept of the Clean Air Zone, five new real-time air quality sensors have been installed in the vicinity of the area to measure NO2. The aim will be to measure the effect of the traffic restrictions on air quality within the Clean Air Zone.
  • Cork City Council will continue its partnership with Cork Healthy Cities and the air quality specialists in University College Cork in collaborating and engaging with the public on air quality issues. For example, a new school’s air quality information and activity pack will be launched in late 2023.

Where’s next?

Later this year Clean Air Together will be moving to Galway City – so watch this space if you’re a resident in Galway City and wish to become a participant!

Clean Air Together

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 and on the EPA website.