These installations reflect the recognition that air quality in Cork — and other Irish cities and towns — needs to improve.

Air pollution causes around 1,300 premature deaths in Ireland every year — about 80 in Cork City alone. That’s almost 10 times more than road traffic fatalities. Poor air quality also exacerbates conditions like asthma, hastens neurological decline in older people, and long-term exposure increases an individual’s vulnerability to transmissible respiratory diseases like Covid.

Air quality is therefore of vital concern to public health and people’s well-being, and the city is right to take it seriously.

But trying to clean the air once it’s polluted, as CityTrees do, is the wrong approach. The primary approach must be to reduce sources of pollution.

As Gary Fuller from Kings College London puts it, cleaning the air is like trying to remove milk from tea — it’s an exercise in futility.

CityTrees lower pollutant levels by 15% within a few metres, but that is not enough to have much impact even on a single street.

Elsewhere, Cork City Council has developed an innovative local air quality programme. So rather than focus on CityTrees, let’s consider what measures councils can take to improve air quality.

Home heating

The main sources of air pollution in Irish towns and cities are the burning of solid fuels like coal, peat, and wood for domestic heating, followed by traffic emissions. Solid fuel burning produces big spikes in particle levels on winter evenings and can reach levels typical of polluted cities in developing countries.

Local authorities could cap the chimneys of council housing as an effective short-term measure to improve air quality, followed by a deep retrofit as funding becomes available. There is also scope to influence household behaviour. 

Research by my colleague, Dr Marica Cassarino in Applied Psychology at UCC, indicates that many households in Cork light fires even when it’s not their primary heating system and therefore not essential to keep warm. Encouragingly, many people indicated that they would consider not lighting fires if alerted that air pollution was forecast to be poor. This is an emerging approach and shows potential to improve local and national air quality.

Transport

Vehicles are major sources of pollution and local authorities have the most influence on transport emissions. Whether for climate or air quality, reducing vehicle usage must become a priority at local and national levels.

Removing barriers to walking and cycling, improving public transport, and re-allocating road space are all needed to reduce traffic emissions.

Although improving bus, rail, and tram options is important, it is walking and cycling that have the greatest potential to promote clean, sustainable travel.

Consider transport in Malmo and Freiburg, two cities similar in size to Cork. Both cities are leading examples of environmental sustainability and have outstanding public transport options. Surprisingly, double to triple the number of people walk or cycle than take the bus or tram.

These figures are encouraging because they show that focussing on active travel can produce quick and effective improvements in air quality and reducing climate emissions.

For these reasons, I expect that pedestrianisation and the installation of protected cycle lanes in Cork over the last year will improve air quality. The new infrastructure is also affecting people’s transport choices, with data from the Strava app showing a doubling in the number of people cycling in the city.

Electric vehicles have a role in improving air quality and reducing climate emissions, but are not “zero emission”, as many claim. They produce significant amounts of particulate matter from road and tyre wear, energy costs of manufacture and recharging are high, and they may discourage active travel.

How about more trees?

Other measures could improve air quality. A campaign against vehicle idling. Messages of electronic roadside boards to promote walking and cycling. Developing clean air zones around schools to protect vulnerable young lungs. Expanding and enforcing bus-prioritisation on St Patrick’s Street, would make public transport more reliable and attractive. Lastly, real trees. Planting of tens of thousands of living trees would capture some air pollutants and make our gardens, estates, and urban spaces more beautiful.

Councils face the challenge that air quality, like climate mitigation, cannot be hived off into an Environment department. A holistic, cross-cutting approach is needed. Spatial development. Roads and transport. Parks. Housing. All affect how we live our lives, the energy we use, and the pollution we produce and breathe in. 

The dire warnings in this week’s IPCC report show that business-as-usual is not an option. The last year has shown that with commitment and urgency, we can change entrenched patterns. And these changes will be for the better.

• Dr Dean Venables is a research group leader in the Centre for Research into Atmospheric Chemistry and a lecturer in the School of Chemistry and the Environmental Research Institute at University College Cork.