Carbon dioxide

I am grateful to Dr Gavin  Whittaker (Letters, 14 March) for introducing me to the latest amendment as to the meaning of pollutant.

By The Newsroom

Published 15th Mar 2013, 00:00 BST

If the effects of CO2-induced global warming are ever established, this variation of the definition may be justified but, until that happens, I will defend the established meaning of the word.

(Dr) PM Dryburgh

Newbattle Terrace

Edinburgh