Maligned gases
Your item (12 March) about trees in Edinburgh removing about 100 tons of carbon dioxide per year contained a misuse of the language.
Carbon dioxide is not a pollutant – it is a constituent of the atmosphere and whether or not any increase of it is bad or not is beside the point.
It is no more a pollutant than oxygen, nitrogen, argon or water vapour would be. This abuse of language may appeal to the global warming faithful but it is still a wilful distortion.
(Dr) PM Dryburgh
Edinburgh