Mowing The Lawn Actually
Increases Summer Smog
London - Scientists have good news for millions of reluctant gardeners - cutting the grass causes pollution.
The smell of a newly-trimmed lawn is caused by a burst of a chemical cocktail from the "wounded" plant.
The dozen substances include methanol, acetaldehyde, acetone and butanone which can cause the summer smog that plagues Britain's cities. And putting clippings on compost heaps make matters worse.
As the grass starts to dry the emissions are stronger and last for hours.
Researchers say that the harvesting of crops adds 1.6 million tons of acetone to the eight million tons released naturally into the atmosphere each year.
Experts at the US National Oceanographic and Atmospheric Administration and Colorado University believe the chemical warfare is a response by plants to being "attacked" by mower blades.
Professor Ray Fall, university head of chemistry and biochemistry, said: "Every time even a cow chomps the grass you get these little surges.
"It seems so unlikely the smell of freshly-mown grass is toxic."