International Regulation of Urban Smog Since the 1940s - Air Pollution and Global Warming: History, Science, and Solutions - page 178

8.1.5. Air Quality Act of 1967
On November 21, 1967, the U.S. Congress passed a
third amendment to the Clean Air Act of 1963, the
Air Quality Act of 1967 (PL 90-148). This act divided
the United States into several inter- or intrastate Air
Quality Control Regions (AQCRs). Officials in each
AQCR conducted studies to determine the extent of
air pollution in the region, collect ambient air quality
data, and develop emission inventories. The act also
specified that the Department of Health, Education,
and Welfare develop and publish Air Quality Criteria
(AQC) reports, which were science-based reports con-
taining information about the effects, as a function of
concentration, of pollutants that damage human health
and welfare. The reports also contained suggestions
about acceptable levels of pollution. Each state was then
required to set and enforce its own air quality standards
based on the acceptable levels suggested in the AQC
reports. The standards had to be at least as stringent as
those suggested in the reports. Each state was required
to submit a State Implementation Plan (SIP) to the
federal government discussing how the state intended
to meet its air quality standards. A SIP consisted of a list
of regulations that the state would implement to clean
a polluted region. If the SIP was not approved by the
federal government or if the state did not enforce its
regulations, the federal government had the authority
to bring suit against the state. If the SIP was approved,
the state was delegated federal authority to regulate air
pollution in the state.
The act also recommended the publication of air
pollution control methods through control technology
documents ,provided funds to states for motor vehi-
cle inspection programs, and allowed California to set
its own automobile emission standards. In 1969, the
CAA63 was amended again to authorize research on
low emission fuels and automobiles.

and it resulted in the transfer of administrative duties for
air pollution regulation from the Department of Health,
Education, and Welfare to the U.S. EPA. CAAA70 spec-
ified that the U.S. EPA design National Ambient Air
Quality Standards (NAAQS) for criteria air pollu-
tants ,socalled because their permissible levels were
based on health-based guidelines, or criteria, obtained
from AQC reports.
NAAQS were divided into primary standards ,
designed to protect the public health (in particular,
that of people most susceptible to respiratory prob-
lems, such as asthmatics, the elderly, and infants), and
secondary standards , designed to protect the public
welfare (visibility, buildings, statues, crops, vegetation,
water, animals, transportation, other economic assets,
and personal comfort and well-being). The U.S. EPA
wasrequired to set primary standards based on health
considerations alone, not on the cost of or technology
available for attaining the standard. Regions in which
primary standards for criteria pollutants were met were
called attainment areas , and those in which primary
standards were not met were called nonattainment
areas .
The six original criteria pollutants specified by
CAAA70 were CO(g), NO 2 (g), SO 2 (g), total suspended
particulates (TSPs), THCs, and photochemical oxi-
dants. Particulate lead [Pb(s)] was added to the list in
1976, ozone [O 3 (g)] replaced photochemical oxidants
in 1979, THCs were removed from the list in 1983, and
TSPs were changed to include only particulates with
diameter

≤

m and called PM 10 , and a PM 2.5 stan-
dard was added in 1997. PM 10 and PM 2.5 are, more
precisely, the concentration of aerosol particles that
pass through a size-selective inlet with a 50-percent
efficiency cutoff at 10- and 2.5-

10

m aerodynamic diam-
eter, respectively. Table 8.2 lists criteria pollutants for
which NAAQS primary and, in most cases, secondary
standards have been set. Secondary standards are the
same as primary standards for most criteria air pollu-
tants. One exception is CO(g), for which no secondary
standard has been set because its major impact is on
human health. A second exception is SO 2 (g), for which
aseparate secondary standard has been set. Table 8.2
also shows California state standards. For all pollutants,
California state standards are stricter than are NAAQS.
CAAA70 further specified that the U.S. EPA design
New Source Performance Standards (NSPS), which
were emission limits for new stationary sources of
pollution. Each state was required to inspect new
stationary sources and certify that pollution controls
indeed worked and would remain working for the

8.1.6. Clean Air Act Amendments of 1970
In late 1970, President Richard Nixon combined several
existing federal air pollution programs to form the U.S.
Environmental Protection Agency (U.S. EPA), whose
purpose was to enforce federal air pollution regulations.
On December 31, 1970, Congress passed the Clean Air
Act Amendments of 1970 (CAAA70, PL 91-604). The
purpose of CAAA70 was

to amend the Clean Air Act to provide for a more
effective program to improve the quality of the Nation's
air,