The reaction has been mixed.

A number of new ‘robot trees’ have appeared on St Patrick Street as part of a Cork City Council drive to make the city air cleaner for residents and visitors.

The City Trees, also known as ‘moss wall’ towers, absorb air pollutants such as particulate matter (PM) and nitrogen oxides (NOx) and emit clean air.

The 1st of our CityTrees were installed today on St Patricks St.

CityTrees help combat fine dust particle pollution &other pollution associated with traffic congestion.

Air pollution causes up to 1,300 deaths each yr, says @EPAIreland

👩‍💻Check out https://t.co/b4H0SfyTJP pic.twitter.com/F5E0kBJabq

— Cork City Council #StaySafe (@corkcitycouncil) August 9, 2021

Made by German company Green City Solutions, each City Tree can do the pollution-zapping work of 275 individual real trees. The CityTree filters 3500 m3 of air every hour, which corresponds to the hourly breathing volume of approx. 7000 people.

The company says the idea is to use a number of the towers to “create a place that invites you to enjoy the space and take a deep breath.”

Sounds rather lovely, actually.

Well done @Corkcoco @corkcitycouncil providing purified air to our #city 💪🙏👏 pic.twitter.com/FjquCUDQDx

— dukes coffee company (@dukescoffeeco) August 9, 2021

Scientific studies by the Leibniz Institute for Tropospheric Research have shown that moss mats clean about 80% of fine dust from the air by ‘trapping’ and ‘eating’ it, making it a sustainable and regenerative fine dust filter.

The pilot project for Cork was first announced in 2020 as part of a €4m green stimulus package. It was later dismissed as ‘a waste of public money’ by Labour’s John Maher.

Much of the confusion seems to come from the belief that the moss towers are an alternative to real trees. However, Cork City Council’s tree planting programme continues apace, with 1300 trees planted in parks and communities across the city throughout 2021.