Page 451 - Fundamentals of Air Pollution 3E

II. Titles 399

Title II: Provisions Related to Mobile Sources
Title II of the Clean Air Act Amendments of 1990 is related mainly to
vehicles that operate on roads and highways. Off-road, or nonroad, engines
and vehicles used for site drilling, remediation, or related construction may
be regulated if the administrator of EPA determines that some degree of
emission reduction is necessary.
The EPA has summarized the provisions related to mobile sources (4) as
follows:
While motor vehicles built today emit fewer pollutants (60% to 80% less, de-
pending on the pollutant) than those built in the 1960s, cars and trucks still account
for almost half the emissions of the ozone precursors VOCs and NO^, and up to
90% of the CO emissions in urban areas. The principal reason for this problem is
the rapid growth in the number of vehicles on the roadways and total miles driven.
This growth has offset a large portion of the emission reductions gained from motor
vehicle controls.
In view of the unforeseen growth in automobile emissions in urban areas com-
bined with the serious air pollution problems in many urban areas, the Congress
has made significant changes to the motor vehicle provisions on the 1977 Clean
Air Act.
The Clean Air Act of 1990 establishes tighter pollution standards for emissions
from automobiles and trucks. These standards will reduce tailpipe emissions of
hydrocarbons, carbon monoxide, and nitrogen oxides on a phased-in basis beginning
in model year 1994. Automobile manufacturers will also be required to reduce
vehicle emissions resulting from the evaporation of gasoline during refueling.
Fuel quality will also be controlled. Scheduled reductions in gasoline volatility
and sulfur content of diesel fuel, for example, will be required. New programs
requiring cleaner (so-called 'reformulated' gasoline) will be initiated in 1995 for the
nine cities with the worst ozone problems. Other cities can 'opt in' to the reformu-
lated gasoline program. Higher levels (2.7%) of alcohol-based oxygenated fuels will
be produced and sold in 41 areas during the winter months that exceed the federal
standard for carbon monoxide.
The new law also establishes a clean fuel car pilot program in California, requiring
the phase-in of tighter emission limits for 150,000 vehicles in model year 1996 and
300,000 by the model year 1999. These standards can be met with any combination
of vehicle technology and cleaner fuels. The standards become even stricter in 2001.
Other states can 'opt in' to this program, though only through incentives, not sales
or production mandates.
Further, twenty-six of the dirtiest areas of the country will have to adopt a program
limiting emissions from centrally-fueled fleets of 10 or more vehicles beginning as
early as 1998.

Title III: Hazardous Air Pollutants
Toxic air pollutants are pollutants which are hazardous to human health
or the environment but which are not specifically regulated by the CAA.
These pollutants are typically carcinogens, mutagens, and teratogens. The
CAAA of 1977 failed to result in substantial reductions in the emissions of
these harmful substances.