Clean Air Together (CAT) is a citizen science project where people voluntarily sign up to measure levels of Nitrogen Dioxide (NO₂) pollution in their local area. NO₂ is a traffic-related air pollutant that can cause negative health impacts. NO₂ particularly impacts children, people with pre-existing heart and lung conditions such as asthma, outdoor workers, the elderly, and those communities who may be more exposed to air pollution because of where they live or work.

The first Clean Air Together campaign took place in October-November 2021 where approximately 1,000 citizens across Dublin successfully measured NO₂ near their home, business, or school. Clean Air Together is a joint project between the Environmental Protection Agency (EPA) and the Environmental Education Unit of An Taisce.

The project aims to create a better understanding of NO₂ air pollution in Dublin. The citizen measurements will help the EPA develop air pollutant mapping and forecasting models for the whole of Ireland in the Life Emerald Project. This will include the development of a near real-time mapping system of air pollution at street level, scheduled for completion by 2023. The air quality maps and forecasts will go on to inform policies aimed at improving air quality and lowering levels of NO₂.

Over 2,500 Dublin residents applied to participate in Clean Air Together (Dublin 2021), with 1000 participant spaces available. This huge level of public interest and the amount of valid results points to a public willingness to participate in citizen science and illustrates the success of the initiative. The EPA and An Taisce therefore extends a massive THANK YOU to all who participated, supported, and gathered important data on traffic pollution in Dublin by measuring NO₂ outside their property. The work could not have been done without you.

The map above shows the NO₂ measurements gathered by CAT participants over four weeks in October-November 2021. You can click on a dot to see the level of NO₂ measured at a location of interest.

The results clearly show the impact of traffic on NO₂ air pollution levels:

the more traffic there is, the higher the levels of NO₂.  

When zooming out on the map you can see a trend emerging: higher results represented as orange and yellow dots are mostly present in the city centre (within the canals) and along some of the major roads around Dublin.

Moving outwards to the suburbs and away from major roads, the measurements drop to lower levels of NO₂ (light blue). Finally, 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. 

 

The pie chart above shows the distribution of Clean Air Together results.

Dark blue represents the lowest NO₂ levels measured. 20% percent of the measurements were dark blue. Most measurements were in the light blue category (66%). 12% of the CAT measurements were in the yellow category, and 2% were in the orange category. No measurement fell into the highest red category.

Locations with the highest results (30μg/m³ – 40μg/m³ and 20μg/m³ – 30μg/m³) were found:

In the city centre within the canals (Grand canal to the South and the Royal canal to the North). They include roads:

• near Trinity College Dublin, Merrion square, St Stephen’s green and in the Liberties to the South of the Liffey
• by Connolly station, Busaras, in trafficked areas of North strand or Phibsboro to the North
• the quays on both sides of the Liffey and by Heuston station (St John’s Road West, Inchicore)

In Dublin city along some of the national roads and regional roads such as:

• the Malahide, Botanic or Swords Roads to the North
• the Donnybrook, Stillorgan roads, Harold’s cross, Kimmage lower and Crumlin roads to the South
• by the M50, especially to the West/North-West near the Palmerstown and Blanchardstown interchanges

By contrast, the lowest results (0μg/m³ – 10 μg/m³) were found in different locations across Greater Dublin’s countryside such as Balscadden (North Dublin County/Fingal), Rathmichael or Old Connaught, or in outer suburban areas such as Stepaside or Saggart.

Light blue dots covered most of Dublin suburbs, especially away from major roads.

The results also suggest that the greater the distance between a dwelling and a busy road the lower the NO₂ levels. NO₂ quickly reduces with distance, for example a long front garden or living on an upper floor of an apartment building can offer some protection against NO₂ pollution. This finding is important asublin continues to grow and change. 

 

 Further information:

• EU Air Quality Directive
• World Health Organisation Air Quality guidelines

 

There are many ongoing initiatives in place that aim to reduce levels of NO₂ in Dublin and Ireland - and there are actions you can take to help too!

 

1) What is being done?

 

The four Dublin Local Authorities, the EPA, and the government have adopted several policy measures including the Climate Action Plan (2021), Dublin’s Air Quality Action Plan (2022), and the New National Investment Framework for Transport in Ireland (2021) comprising actions that will 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 Dublin and two zero-emissions hydrogen buses.
• 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.

 

 2) What can YOU do?

 

There are many simple steps you can take. Collectively, these steps can have a big impact on reducing the levels of NO₂ across Dublin.

YOU can:

• Think twice before using your car. One less journey a day or week can make a big difference!
• Try to walk or cycle on shorter trips instead of using your car. This emits zero emmissions and is a step towards a healthier lifestyle. Enquire with your company about the Bike to Work Scheme, safe and secure cycle parking and changing facilities at work.
• Use public transport if it is an option for you instead of driving for longer journeys.

• Alter your driving habits and switch off your engine when your vehicle is stopped. This helps to reduce NO₂ emissions and reduce the amount of pollutionpedestrians and cyclists will breathe in from your vehicle
• Support flexible working arrangements such as home working to reduce the number of vehicles on the road
• Raise any concerns with your local public representative and get their support for cleaner air and healthier communities
• Could you consider an electric vehicle for your next purchase?
• Consider buying more local goods. Many items have travelled long distances to get to the supermarkets and each journeyyour purchased goods have made raises the amount of air pollution for other citizens and animal life on the planet

 

Nitrogen dioxide (NO₂) is an air pollutant that mainly comes from vehicle traffic. NO₂ levels change throughout the year because of:

• Traffic: As NO₂ is a traffic related pollutant, the emissions are higher around busy roads than quiet country roads.
• Weather: Weather can significantly influence how much NO₂ is in air we breathe. In windy weather, pollution can move around whereas on very still, warm days pollution can hover, and may be higher.
• Ventilation: The size of your surrounding streets can affect how much air pollution is in your area. A narrow street with tall buildings can be more polluted than a wide street with lower buildings as there is less space for air to move around.

 

Why does NO₂ matter for your health and the environment?

 

Being exposed to NO₂, even for short periods, can have harmful effects on our health and wellbeing. Short-term exposure to NO₂ is linked to adverse respiratory effects including airway inflammation in healthy people and increased respiratory symptoms in asthmatics. Long-term exposure is associated with increased risk of respiratory infection in children. Research from Trinity College shows that over 50’s living in Ireland in areas with higher levels of NO₂ are more likely to have asthma.

NO₂ pollution also impacts the environment. It affects the quality of fresh water, soil, and ecosystems, and NO₂ can be absorbed to the atmosphere and later fall as something called ‘acid rain’ that can damage plant life and buildings. NO₂ also behaves like a greenhouse gas.

EPA monitoring and computer modelling shows that in some urban areas NO₂ pollution is increasing. The EPA in collaboration with the Local Authorities manages a national network of air monitoring stations. The EPA has 97 monitoring sites throughout the country, 13 of which measure NO₂ in Dublin. Real-time air pollution data can be seen on www.airquality.ie.

While NO₂ is one of the main ambient air pollutants of concern in Dublin, there are other air pollutants of high concern such as Particulate Matter (PM). To learn more about how other air pollutants can impact your health and the environment, and what is being done to lower their levels go to www.airquality.ie.

 

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Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it's the only thing that ever has.