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Special Characteristics
A critical examination of the emissions
control application suggests that these systems may operate effectively for much of a
vehicles useful life, but ultimately, many of these systems may degrade and exhibit highly
variable behavior that is accompanied by gross emissions of hydrocarbons, CO, and NOx.
Thus, the issue is not to develop systems whose performance when new is exemplary. Rather,
it is to develop reliable maintenance free emission control systems that will operate at
close to new car levels when a vehicle is well past 100,000 miles and into its third,
fourth, or fifth level of ownership. This remains a major challenge, particularly if years
of neglect and poor maintenance are considered. In general, it seems plausible to think
that reliable emission control systems for exhaust and evaporative emissions hold the key
to reducing urban emissions and ozone formation in many areas, particularly in California,
where 40 percent of vehicles have more than 100,000 miles on their odometer. The
United States is
pre- eminent in this technology area, driven by our commitment to clean air.
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