Ozone in its place

Ozone is to science what 1066 is to history. If there’s one thing we know about chemistry (and there may not be) it is that ozone is jolly good and should be encouraged. So a mostly unspoken hip-hip hooray greeted news that the hole in the ozone layer has shrunk. That is attributed to the change in refrigerator and aerosol chemicals since 1985, when the world signed the Montreal Protocol. Yet ozone might not be quite what we think. P G Wodehouse gave the popular view when he said the zippiness of New York was caused by “something in the air, either the ozone or the phosphates or something”. In reality ozone, a poisonous gas, irritates eyes and lungs. It does sterling work in the stratosphere as the Earth’s Factor 40 sunblocker. At ground level it makes smogs sting, and no zone is improved by ozone.