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]]]]]]]]] DIRTY-CAR TUNEUPS BEAT OXY-FUELS BY A MILE [[[[[[[[
By Donald H. Stedman (2/6/90)
Mr. Stedman is a professor of chemistry
at the University of Denver.
[From The Wall Street Journal, 6 February 1990, p. A18:3]
[Kindly uploaded by Freeman 10602PANC]
Every version of the Clean Air Act currently under
consideration contains provisions for mandating alternative
fuels. Cost estimates reviewed for the Business Roundtable vary
from $40 million to several billion dollars a year. Millions of
dollars are already being spent in Arizona, Colorado, Nevada and
New Mexico on the mandated use of oxygenated fuels in vehicles as
a carbon-monoxide control measure.
Yet the same Environmental Protection Agency database used to
justify the use of oxygenated fuels shows there's a better way to
control carbon-monoxide emissions: Tuning up the small minority
of dirty cars is twice as effective as -- and much cheaper and
simpler than -- using oxygenated fuels in the entire fleet.
At the University of Denver, we have analyzed the studies of
oxygenated fuel on vehicle emissions in the EPA's national
database and other available studies. The results from all the
studies are striking in their similarity.
Half the carbon monoxide emitted comes from about 10% of the
vehicles tested. Half the improvement in the per-mile carbon
monoxide emissions attributed to fuel oxygenation comes from the
same 10% of the fleet. If those few vehicles were to have their
emissions systems tuned up to equal the average of the rest of
the fleet, the emissions improvement would be almost twice as
large as the improvement obtained by using oxygenated fuel for
the entire fleet.
As an example, an EPA study of 84 vehicles published last year
showed that 80 of them emitted a total of 397 pounds of carbon
monoxide, while the dirtiest four emitted 338 pounds [85.1% of
the base]. When the entire fleet was put on oxygenated fuel, the
total emissions reduction was 203 pounds [57.9% of the base],
with the dirty four contributing 107 pounds of that improvement
[52.7% of the improvement]. If the dirty four were tuned to emit
the average of the rest of the fleet, they would emit a total of
20 pounds -- a 318-pound reduction in emissions [80.1% of the
base] from the tuning up of only four vehicles.
Oxygenated fuels cost more, decrease gas mileage and damage
vehicle components. Therefore, a program that identifies and
mandates tuneups for just the gross polluters offers major
advantages.
An actual tuneup study of 10 vehicles was conducted in 1978 by
the Colorado Department of Health. The 10 vehicles studied
emitted a total of 434 pounds of carbon monoxide using normal
gasoline. When 10% ethanol fuels were used, the fleet emission
dropped to 335 pounds [77.2% of the base]. When only the two
dirtiest cars were tuned up, and the normal fuel retained, the
fleet emissions dropped to 294 pounds [67.7% of base].
Last summer, there was a widely publicized rally for
methanol-fueled vehicles. It was not widely publicized that the
emissions from those specially prepared vehicles were essentially
identical to those from any new vehicle that could have been
bought from any showroom nationwide. It is tempting to suggest
that the problem is not dirty fuels, but dirty cars.
The University of Denver has developed a remote sensing device
that can detect carbon-monoxide emissions from passing vehicles.
The results of more than 250,000 measurements agree with the
statistics from the government testing programs; namely, half the
carbon monoxide emitted comes from about 10% of the vehicles. We
now have a tool to identify the gross polluters very cheaply.
All the data show conclusively that a good tuneup of a few
vehicles would be more cost effective than mandating less
efficient fuels for everyone.
Mandated oxygenated-fuel programs cost an estimated $500 per
ton of carbon monoxide removed, according to a study prepared for
the EPA last September by RCG/Hagler, Bailly Inc. (The estimate
does not include a realistic assessment of gas mileage lost, or
any estimate of vehicle-parts damage.) Annual exhaust-pipe
inspection and maintenance programs cost more than $780 per ton
of carbon monoxide removed. A program based on remote sensing
and tuneups of the gross polluters would cost, I estimate, only
$40 per ton.
All the studies point to the cost-benefit advantages of this
program. The choice is clear.
* * *
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