The word may have initially been used to describe male wet dreams – but now there is no aspect of our environment that we are not intent on profaning

Air pollution in big cities, we learned this week, causes large reductions in intelligence, which is perhaps one good reason for moving Parliament out of London. Toxic air is a scientific and health issue, but the way we speak of it has religious roots.

“Pollution” comes from the Latin for the desecration of a sacred space, spiritual or moral corruption, or general filth. In the middle ages it was adopted in French for nocturnal emissions of the kind that emanated from sleeping male sinners. Nowadays, of course, we happily chuck all kinds of stuff into rivers, seas and the air, including warming carbon dioxide and NOx, or nitrogen oxides. Add noise pollution and light pollution, and it seems there is no aspect of our environment we are not intent on profaning.

The vestigial sense of the sacred in our idea of pollution chimes with the spiritual rhetoric of some environmentalists seeking to protect Gaia, the Earth goddess. China, where the pollution study was conducted, by contrast boasts of a gruff military approach, having declared “war on pollution” five years ago. As with so many wars, it may be a long time yet before the belligerents can breathe easy.