Controversial ‘robot trees’ have been installed in Cork city centre to help to clean pollutants from the air.
Five high-tech CityTrees, costing some €350,000 for the year including maintenance, are being installed at St Patrick’s St and on the Grand Parade near the City Library.
CityTrees are large structures covered in mosses designed to filter harmful pollutants such as fine dust particles and nitrogen oxides (NOx) from the air.
The moss acts as a filter to ‘trap’ and ‘eat’ fine dust, making it a sustainable and regenerative fine dust filter.
Scientific studies by the Leibniz Institute for Tropospheric Research have shown that these 'moss mats' clean about 80% of fine dust from the air.
The CityTrees also have in-built sensors to collate air quality data for analysis and 40-inch TV screens to share information about air quality in the city. They also feature a built-in chair to act as street furniture.
Cork City Council said that they form one part of its strategy to tackle pollution, which also includes the planting of 1,300 trees this year.
“These are not there to replace a tree. A tree takes in carbon dioxide and releases oxygen," said David Joyce, operations director, Cork City Council.
“These CityTrees take in particulate matter — dust — from diesel engines, from burning fossil fuels, and it captures that dust and eats the dust so it takes 80% of that dust out of the air.
The project is funded by the Government. It is one of more than 500 such projects in 11 counties funded as part of a €55m National Transport Authority funding package announced under the July stimulus plan in response to the Covid-19 crisis.
The funding is to support pedestrian and cyclist movement and to enhance accessibility in cities, towns, and villages.
But atmospheric scientist Dean Venables said that the devices are “a costly and ineffectual gimmick” and will have no meaningful impact on the city’s air quality.
Dr Venables, a researcher at the Centre for Research into Atmospheric Chemistry at University College Cork, told thethat Ireland's core strategy has to be about reducing emissions, not just clawing back some of the pollution after the fact.
He said that although the CityTrees may clean the air in the immediate vicinity of the structures, they would have no discernible impact on overall air quality in the city.
“The most important strategy has to be to reduce emissions," he said.
"You need to stop emissions of carbon as well rather than capture them and try to claw back.
"Burning solid fuel — coal, peat, wood — causes the worst pollution in Cork City. In the city centre, during the day, the main problem will be traffic fumes. Ireland has a large diesel fleet which produces particulate matter and nitrogen oxide.
"While I am critical of the CityTrees approach, what is positive is that air quality is recognised as an issue by the city council. As a result, Cork has the most innovative national approach to air quality monitoring with a network of low-cost sensors across the city. Monitoring air quality will not, by itself, improve air quality, but such measurements are the first step to raise awareness of the importance of air quality as a major public health issue."
An Rabharta Glas councillor Lorna Bogue said that she has been getting “a lot of contact” about the “robot trees”.
Ms Bogue had been working on establishing a large-scale tree-planting project in Cork City and said that certain tree species such as lime trees are very effective at absorbing contaminants from the air.
And real trees would also contribute to a cooling effect by blocking sun from hitting the tarmac.
Air pollution is responsible for up to 1,300 deaths in Ireland each year, according to the Environmental Protection Agency.
According to Build Up, the European portal for energy efficiency in buildings, every CityTree reduces local air pollution in a proximity until 50m by up to one-third.
One CityTree equals 275 natural trees and can convert 240 tons of CO2 equivalents from dust pollution and soot per year, it said.
The CityTrees are self-sustaining with energy and water due to connected solar cells and rain water collection systems and need only a few hours of maintenance per year.