The poisonous residue from car exhausts is causing a public health crisis and could be the death of sparrows too
You may never have heard of cow parsley syndrome, yet its been visible over much of Britain for the past month the spectacle of country roads fringed with a dense throng of tall white feathery flowers, three- to four-feet high, which many people now think of as an attractive addition to the landscape. Its a pity they do, for the point about the syndrome is this: theres lots of cow parsley, sure. But there isnt anything else.
Along mile after mile of our rural highways, especially the closer you get to London, every spring you will see masses of this frothy foam. But what you often wont find is the lovely variety of wildflowers that 30 to 40 years ago decorated these same roadside verges: comfrey, ladys smock, white dead-nettle, garlic mustard, birds-foot trefoil, ox-eye daisy, early purple orchid and many more. The cow parsley has largely crowded them out because it has been fertilised into excessive growth. Much of the fertiliser has come in the form of nitrogen compounds from car exhausts, especially diesel ones a striking example of how air pollution from motor vehicles is impacting on the natural world.
People get that. Absolutely. But what is not nearly so well appreciated is the way in which air pollution is now playing havoc with the natural environment too, principally through the atmospheric deposition of nitrogen compounds and perhaps also through particulates, the microscopic soot particles that diesel engines emit.