21/05/2007

Idling Worse Than Re-starting Diesel Engines

Shut off those diesel school bus engines! That was the clear message delivered
by Alan J. Steinberg, US Environmental Protection Agency (EPA) Regional
Administrator at a press conference. EPA studied school bus exhaust levels when
the buses were parked but engines kept running and calculated the benefits from
turning them off for various periods and then restarting them. The study
concluded that idling for more than three minutes generates more pollution than
stopping and re-starting the engine ­ debunking a widely held belief of some
drivers. Turning the engine off cuts carbon monoxide, fine particles, nitrogen
oxide, and carbon dioxide ­ a greenhouse gas.

"Pollution from school buses has health implications for everyone, especially
asthmatic children," said Alan J. Steinberg, EPA Regional Administrator. "This
study shows in no uncertain terms that allowing a bus to idle exposes children
to more pollution and shows that a very simple step ­ shutting off that engine
­ can really make a difference."

Under the study, EPA measured the pollution from six buses. The level of
pollution from buses that idled for more than three minutes was 66% higher in
fine particles than pollution generated from shutting off the buses then
re-started.

Diesel exhaust particles can penetrate deep into the lungs and pose serious
health risks, including aggravating the symptoms of asthma and other
respiratory problems in healthy individuals. The Northeast has some of the
highest asthma rates in the nation, including childhood asthma rates near 12
percent in areas of New York City.

Due to the longevity of diesel engines, it is estimated that about one-third of
all diesel school buses now in service were built before 1990. Older buses are
not equipped with today's pollution controls or safety features and are
estimated to emit as much as six times more pollution as the new buses that
were built starting in 2004, and as much as sixty times more pollution as buses
that meet the 2007 diesel standards. There are steps that school bus operators
can take now to reduce pollution levels including idling reduction programs,
anti-caravanning practices, ensuring proper maintenance of engines, and
replacing and retrofitting older buses.

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AplusA-online.de - Source: Environmental Protection Agency