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PETROL-driven lawnmowers in Europe should be fitted with catalytic
converters. Until then the sweet smell of freshly cut grass wafting across
suburbia will continue to be mixed with alarming quantities of cancer-causing
chemicals.

A pioneering study by Roger Westerholm, an analytical chemist at Stockholm
University, has found that one hour鈥檚 mowing produces as much polycyclic
aromatic hydrocarbons (PAHs) as a 150-kilometre drive in an average car. The 4
milligrams of PAHs emitted by the exhaust of a typical Swedish mower in an hour
included 鈥渞elatively large amounts of carcinogenic PAHs鈥�, Westerholm says.

He found 26 different PAHs in the mower exhaust, including 100 micrograms of
benzo[a]pyrenes, which are widely implicated as a carcinogen in cigarette smoke.
The lawnmower also emitted more than half a kilogram of carbon monoxide, and
several grams each of methane, hydrocarbons, nitrogen oxides and smoke
particulates.

Westerholm says that mowers and other petrol-powered garden tools such as
leaf blowers and chainsaws should follow the example of cars and be fitted with
catalytic converters. 鈥淚n the tests, catalytic converters cut PAH emissions by
more than 90 per cent,鈥� he says. They also cut most other pollutants by between
30 and 50 per cent. 鈥淯sing a catalyst would help prevent most emissions from
small engines. Of course, people could use an electrically powered lawnmower
instead,鈥� he adds.

Many lawnmowers in the US are less toxic than European models, says
Westerholm, because of pollution regulations introduced in 1998 covering
鈥渘on-road鈥� engines. Prior to these regulations, up to one-tenth of the PAHs in
the air in American suburbs came from garden machinery.