Lecture 05: U.S. Clean Air Act,
Exceptional Events
Atmospheric Chemistry and Air Pollution, 2016
Today’s Objectives
• History of air quality regulation in the U.S.
• Evolution of Clean Air Act
• Role of “exceptional events” within Clean Air Act
Reading: Chapt. 8 of Jacobson
Air Pollution Review 1940s, 1950s
1940s: Smog severe in Los Angeles
1947: Los Angeles Air Pollution Control District forms
1948: Donora, Pennsylvania smog disaster
1949: National symposium on air pollution in Los Angeles
1951: Oregon approves agency to control air pollution
1952: Air pollution disaster in London
mid-1950s: Ozone levels in Los Angeles reach 0.65 ppmv
1955: President Eisenhower asks Congress to examine air pollution
Air Pollution Laws 1950s
U.S. Air Pollution Control Act of 1955
Federal technical assistance to state air pollution control
Funding of Public Health Service for studies of air pollution
Did not impose regulations on air pollution
Delegated regulation to state and local level
U.S. Air Pollution Laws
1959
California Motor Vehicle
Control Board set f irst auto
emission standard worldwide.
1963 model cars required to
reroute crankcase hydrocarbon
emissions back to manifold for
reburning.
1960 NOx control device
1959 Corvette
Awesomecarauctions.com
aqmd.gov
Motor Vehicle Air Pollution Control
Act of 1965
First regulation of automobiles at federal
level
Emission standards to reduce tailpipe
hydrocarbons (HCs) 72%, CO(g) 56%
For 1968 model cars; patterned after
California for 1966 cars
More than half of 1968 and 1969 cars did
not meet standard
[released in 1971]
Dipity.s3.amazonaws.com
Air Quality Act of 1967
U.S. divided into Air Quality Control Regions (AQCR)
Required publication of Air Quality Criteria (AQC) reports
Science reports about effects of pollutants on health/welfare
Provide suggestions about acceptable levels of pollution
States set their own standards based on AQC reports
State Implementation Plans (SIP)
State plan for regulation submitted to federal government
If no state enforcement, federal government could sue state
EPA Regions
www.croll.com
Clean Air Act Amendments of 1970
Creation of U.S. Environmental Protection Agency (USEPA)
National Ambient Air Quality Standards (NAAQS)
Primary: to protect public health (e.g., asthmatics, elderly)
Secondary: to protect public welfare (e.g., visibility, buildings)
Criteria Air Pollutants
Originally: CO(g), NO2(g), SO2(g), total suspended particulates
(TSP), hydrocarbons (HCs), “oxidants”
Lead added in 1976
“Oxidants” change to O3(g) in 1979
HCs removed in 1983
TSP changed to PM10; PM2.5 added in 1997
Clean Air Act Amendments of 1970
Attainment areas
Regions where primary standards met
Nonattainment areas
Regions where primary standards were not met
New Source Performance Standards (NSPS)
Set by USEPA to limit emission from new stationary sources
National Emission Standards for Hazardous Pollutants (NESHAPS)
For pollutants causing mortality, severe illness
Initially, for, asbestos, beryllium, mercury. List expanded in 1984
Congressional control of automobile emissions
Required 90% reduction HCs, CO(g) by 1975 and NOx by 1976
Reduced to 70 ppbv in
2015
History of Ozone NAAQS
htp://www3.epa.gov/tn/naaqs/standards/ozone/s_o3_history.html
State Implementation Plans
“...the use of SIPs, which originated with the Air Quality Control
Act of 1967, continued under CAAA70. CAAA70 required that
SIPs address primary and secondary standards. Through a SIP,
each state was required to set ambient air quality standards at
least as stringent as federal standards, evaluate air quality in
each AQCR within the state, and establish methods and
timetables for improving air quality in each AQCR to meet state
standards. The SIP was required to address approval
procedures for new pollution sources and methods of reducing
pollution from existing sources. Once submitted, a SIP required
U.S. EPA approval; otherwise, the U.S. EPA had the power to
take control of the state's air pollution program.”
Jacobson, Sect. 8.1.6
CAFE Standards
1975: Energy Policy Conservation Act
Gave National Highway Traff ic Safety Administration
(NHTSA) right to set Corporate Average Fuel Economy Standards
for cars and light trucks (<3900 kg) & SUVs < 4500 kg
1978
First CAFE standard for passenger vehicles 18 mpg
1990-2010
27.5 mpg
2011
30.2 mpg
Clean Air Act Amendments of 1977
Prevention of Signif icant Deterioration (PSD) in areas already under
attainment. Three classes of regions designated:
Class I: Pristine areas (parks, wilderness) no new sources
Class II: Moderate changes allowed but regulations desired
Class III: Major growth allowed if NAAQS not exceeded
PSD permit needed for growth in region allowing growth
New source must use Best Available Control Technology
(BACT)
Computer modeling mandated to check whether new pollution sources
might result in standard exceedence
Control of CFCs (which lead to stratospheric ozone loss)
Nonattainment Areas
Nonattainment Areas
Clean Air Act Amendments of 1990
1990: 96 cities still in violation of ozone NAAQS
--> nonattainment areas divided into six categories
“Extreme:” Los Angeles
“Severe:” Baltimore, New York, Chicago, Houston
New sources in nonattainment areas must achieve
Lowest Achievable Emissions Rate (LAER) by
adopting Reasonably Achievable Control Technology
(RACT)
Hazardous Air Pollutants (HAPs)
Emission limits for 189 toxic chemicals using
Maximum Achievable Control Technologies (MACTs)-can consider cost, non-air quality health & environmental
benef its
More control of CFCs
Trans-State Boundary Pollution
“Section 126 of CAAA70 allows downwind states to file
petitions with the U.S. EPA to take action to reduce
emissions in upwind states when such emissions make it
difficult for the downwind state to meet federal air quality
standards”
Sect. 8.1.13 of Jacobson
What is the “AQI”
What is the “AQI”
http://airnow.gov/index.cfm?action=aqibasics.aqi
How is AQI calculated?
How is AQI calculated?
Q: What does AQI = 100 mean?
How is AQI calculated?
How is AQI calculated?
How is AQI calculated?
Q: Can you think of some potential issues with use of the AQI?
Trends in Air Quality
U.S. Air Quality Trends 1980-2009
Figure 8.1, USEPA (2011)
Trends in Air Quality
U.S. Air Quality Trends 1980-2009
Q: why the dramatic decline in Pb (lead)?
Figure 8.1, USEPA (2011)
Trends in Air Quality
Visual Range Trends 30 U.S. National Parks
Visibility lower in
the East, b/c RH
higher in the East,
so aerosol particles
have greater liquid
water contents and
larger sizes
“Exceptional Events”
What is a “Natural Event”?
Q: Can you think of some natural events?
Examples of Exceptional Events
(1) Chemical spills and industrial accidents
(2) Structural fires
(3) Exceedances due to transported pollution
(4) Exceedances due to a terrorist attack
(5) Natural events
Examples of Exceptional Events
(3) Exceedances due to transported pollution
Could be crossnational, or even crossstate borders
Examples of Exceptional Events
(5) Natural events
Exceptional Event Demonstrations