THE true cost of Hereford's moss carbon dioxide filters has been revealed.

A freedom of information request to Herefordshire Council has revealed the costs of installation and maintenance of the filters as well as how much carbon dioxide they have removed from the air.

Hereford currently has three moss filters in, near Trekkit in Eign Gate, near The Courtyard in Edgar Street, and at the Eign Street bus stop.

The Eign Gate filter became operational in June 2022, while the other two became operational in June 2023.


And thousands have been shelled out by Herefordshire Council for them, with the information revealing that the purchase price of the Edgar Street filter was £40,374.54 while the Eign Gate filter cost £43,911.27, and the Eign Street filter cost £34,291.35.

Running costs for all three units, which has included labour, capital replacement parts, replacement of moss mats and reporting and monitoring data for 60 months has cost an additional £61,048, Herefordshire Council said.

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The council said the filter units have been estimated to produce a reduction of approximately 342kg of carbon dioxide per year (on a moss filter footprint of 9m2), with the moss using it during photosynthesis and producing oxygen as a by-product.

It said the three units have in total also filtered 580.6g of fine particulate matter, which makes up a large part of city air pollution, from the air.

What do moss filters do?

Herefordshire Council said the moss filters were installed as part of a range of measures to "enhance the city centre environment", with improvements aimed at encouraging people to spend more time in the city when they visit and funded jointly by the council and Marches LEP.

The council said moss has "possibly the best air cleaning and oxygenating capabilities of any plant, so is one of nature's best air filters", and that the "enormous surface area of moss" mean the filters are more efficient at filtering and cooling the air around them than trees.

The moss mats are claimed to be able to clean around 80 per cent of fine dust and particles from the air, and using ventilation technology filters breathing air for up to 7,000 people per hour