Transcript Document

Chapter 11
Improving Air Quality:
Controlling Mobile Sources
© 2004 Thomson Learning/South-Western
Urban Air Pollution: An Important Policy
Motivation
 Measuring U.S. Air Quality
Air quality index (AQI) – an index that signifies the
worst daily air quality in an urban area over some
time period
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Urban Air Pollution: An Important Policy
Motivation
 Urban Smog
Photochemical smog – a type of smog caused by
pollutants that chemically react in sunlight to form
new substances
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Controlling Mobile Sources
 Brief Retrospective on Motor Vehicle
Emission Controls
1963 – Congress passed into law the Clean Air Act,
the first extensive set of air quality standards
Early years of mobile source controls were marked
by a series of extensions and a chronicle of delays
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Controlling Mobile Sources
Figure 11.2 National Emissions Estimates for Mobile Sources by
Major Category for 1999
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Controlling Mobile Sources
 Current U.S. Controls on Motor Vehicles and
Fuels
1990 Clean Air Act Amendments strengthened U.S.
controls on motor vehicle emissions and fuels
Included incentives to encourage technological
development of cleaner-running vehicles and
cleaner alternative fuels
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Controlling Mobile Sources
 Emission reductions for motor vehicles
Onboard Pollution Control Systems for Light-Duty
Vehicles
Fuel Quality Controls
Reformulated gasoline – newly developed fuels that
emit less hydrocarbons, carbon monoxide, and
toxics than conventional gasoline
Oxygenated fuel – formulations with enhanced
oxygen content to allow for more complete
combustion and hence a reduction in CO
emissions
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Controlling Mobile Sources
Clean Fuel Vehicles – a vehicle certified to meet
stringent emission standards
Clean alternative fuels – fuels such as methanol,
ethanol, or other alcohols, or power sources, such
as electricity, used in a clean fuel vehicle
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Economic Analysis of Mobile Source
Controls
 Absence of Benefit-Cost Analysis: An
Inefficient Decision Rule
Technology forcing – by design specifically set to
compel the auto industry to find solutions
Benefit-based – standards set to protect public
health and welfare
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Economic Analysis of Mobile Source
Controls
Figure 11.3 Inefficiency of a Benefit-Based Decision Rule on
Motor Vehicle Emissions
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Economic Analysis of Mobile Source
Controls
 Uniformity of Auto Emissions Standards
Ongoing problem with U.S. mobile source controls
is that with few exceptions the emission standards
are applicable across the board on every model
produced and without regard to where the vehicle
will be driven
Uniform standard
Two-tiered standard
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Economic Analysis of Mobile Source
Controls
 Inherent Bias Against New versus Used
Automobiles
One dilemma of environmental law is the inherent
bias caused by more stringent controls placed on
new polluting sources
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Economic Analysis of Mobile Source
Controls
Figure 11.5 Modeling the Bias Against New Automobiles
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