Cork City Council has defended its decision to spend €350,000 on robotic trees that clean pollutants from the air, which an academic has described as "a costly and ineffectual gimmick".
The five trees were purchased as part of a plan to improve air quality throughout the city over the next five years. They are located on Patrick Street and Grand Parade.
Council's director of operations David Joyce said the 4m-high units purchased as part of the City Trees Project filter pollutants generated by traffic out of the air. He said each unit could sift an amount of air equivalent to that needed by up to 7,000 people every hour.
Council executive scientist Kevin Ryansaid the units contain a specialised culture of moss that absorbs pollutants such as particulate matter and nitrogen oxides generated by traffic and then emit clean air.
He said studies by the Leibnitz Institute for Tropospheric Research in Germany found that the moss – located on trays held within the slatted timber units – cleans about 80 per cent of fine dust from the air.
Dr Dean Venables of University College Cork's Centre for Research into Atmospheric Chemistry commended the council for being the first in Ireland to introduce an air-quality strategy. But he said the city trees element is "a costly and ineffectual gimmick".
While the units may clean the air in their immediate vicinity, he said they would have no discernible impact on overall air quality in the city and Ireland’s core strategy to improve air quality should remain the reduction of emissions.
Mr Joyce said the units were just one aspect of the council’s air-quality strategy and should be considered in tandem with moves such as the pedestrianisation of 17 city streets and the introduction of 75 electric vehicles by the council.
“We need to reduce emissions across the city and anybody who reads our air-quality strategy will see that there are significant long-term and city-wide strategies to reduce the impact of pollutants across the city. However, that is something that is going to take time and take money,” he said.
He said the Cork Area Metropolitan Transport Strategy 2040 involved an investment of €3.5 billion in more environmentally friendly and sustainable means of transport and would hugely improve air quality, but the plan would take years to realise.
“So rather than waiting until that is delivered and sitting on our hands and doing nothing in the interim, it makes sense for us to implement short- and medium-term interventions to help improve the air quality. And that is what the City Trees Project is aimed at achieving,” he said
Mr Joyce said the city trees were not a substitute for the real variety, 1,200 of which would be planted across across the city this year with 1,500 to follow in 2022.