Environmental Information
PREVENTING SIGNIFICANT DETERIORATION OF AIR QUALITY
IN CLEAN AIR AREAS
INTRODUCTION
A major purpose of the Clean Air Act of 1970 is "to
protect and enhance the quality of the Nation's air resources
so as to promote the public health and~welfare and the pro-
ductive capacity of its population." The Act is administered
by the U.S. Environmental Protection Agency (EPA).
Under the Act, States are required to develop and carry
out State Implementation Plans (SIPs) to achieve and maintain
national ambient air quality standards established by EPA.
The standards set clean air goals to protect health (primary
standards) and welfare (secondary standards).
The Act has been interpreted by the courts as,also barring
degradation of air in areas that are cleaner than the national
ambient air quality standards require.
EPA has issued regulations to provide ways in which States
can protect air quality in areas where the air is already
cleaner than is required by the standards. The background of
these regulations is this:
On May 30, 1972, as a result of a suit filed by the Sierra
Club, EPA was ordered by the District Court of the District of
Columbia to disapprove all State Implementation Plans which did
"not prevent significant deterioration of air' quality" in
currently clean air areas.. EPA was ordered to publish regu-
lations to this effect. The District Court order was appealed
by EPA to the U.S. Court of Appeals where it was affirmed, and
subsequently to the U.S. Supreme Court where it was affirmed by
a tie vote.
Following the initial court action, EPA disapproved all
State Implementation Plans which did not explicitly "prevent
significant deterioration."
There was no firm judicial or legislative guidance available
to EPA on what constituted significant deterioration or on how
to prevent such deterioration. Nevertheless, after extensive
public comment was analyzed, EPA published final regulations in
the Federal Register on December 5, 1974.
U.S. ENVIRONMENTAL PROTECTION AGENCY, WASHINGTON, D.C. 20460
-------
-2-
WHAT THE REGULATIONS DO
The regulations establish three classifications of air
quality levels based on how much increase will be permitted
.in ambient concentrations of particulate matter, such as dust,
soot and smoke, and of sulfur dioxide.
Class I — regions where practically any air quality deteri-
oration would be considered significant. In this class, the
annual mean increases in present pollution levels would be
limited to five micrograms of particulates per cubic meter of
air and to two micrograms of sulfur dioxide per cubic meter
of air.
Class Il — regions where deterioration in air quality that
would normally accompany moderate, well-planned growth, would
not be considered significant. The allowable annual mean
increase would be limited to 10 micrograms of particulates and
15 micrograms of sulfur dioxide per cubic meter of air.
Class Ill — regions where intensive major industrial growth
is desired. But levels of particulates and sulfur dioxide
would not be allowed to rise oeyond the point of the most
stringent Federal air standards to protect the public health
and welfare.
EPA designated all areas of the country as Class II bearing
in mind the twin objectives of the Clean Air Act to protect air
quality and "promote...productive capacity."
REDESIGNATION
Under the EPA regulations, the States (including sovereign
Indian governing bodies) may request redesignation of an area
to Class I or Class IM. Managers of Federal land, however, may
request redesignation only from Class II to Class I.
The redesignation of an area may be necessary to achieve
the social, economic or environmental objectives of its popu-
lation or of the Nation as a whole. The regulations give the
primary decision-making responsibility to the States to help
them achieve their various objectives.
Requests for redesignation must reflect full consideration
of environmental, economic and social effects of the classification
change on the affected area and on the surrounding region and
the Nation as we!1.
The public must be involved. Full public participation
is an essential element of the redesignation process. An
analysis of the anticipated effects of a classification change
must be made available to the public prior to and at a public
hearing on the proposed redesignation.
-------
-3-
HOVJ THE REGULATIONS WORK
The prevent-on of significant air quality deterioration
is to be achieved by a review of major sources of industrial
air pollution prior to plant construction. A list of the
industries regulated follows:
1. Fossil-fuel fired steam electric plants of more than
1,000 million B.T.U. per hour input.
2. Coal cleaning plants (i.e., thermal dryers).
3. Kraft pulp mills (i.e., recovery furnaces).
4. Portland cement plants.
5. Primary zinc smelters.
6. Iron and steel mills (i.e., metallurgical furnaces).
7. Primary aluminum ore reduction plants.
8. Primary copper smelters.
9. Municipal incinerators capable of burning more than
250 tons of refuse per day.
10. Sulfuric acid plants.
11. Petroleum refineries.
12. Lime plants.
13. Phosphate rock processing plants.
14. By-product coke oven batteries.
15. Sulfur recovery plants.
16. Carbon black plants (i.e., furnace process).
17. Primary lead smelters.
18. Fuel conversion plants.
19. Ferroalloy production facilities.
EPA has established criteria published in the September 10,
1975, Federal Register to add other source categories. Such
sources would be those that emit more than 25 pounds per hour
of particulate matter or sulfur dioxide and have a New Source
Performance Standard. (This standard limits emissions from new
industrial plants.)
-------
-4-
EPA significant deterioration regulations require that new
or modified sources use the best available control technology
to limit their emissions. Industrial development in clean areas
will not only be well planned and orderly but will cause less
pollution than earlier developed industrialized areas., which
now must be cleaned up.
Applications for permission to build any of these new air
pollution sources will not be approved without a determination
that the air quality level in the class concerned will not be
exceeded.
The regulations offer the States and local governments
an opportunity to assume responsibility to review and approve
applications for new industrial development.
Decisions arising from the new regulations are too important
to be left to technicians alone. Government at all levels must
seek out the advice of affected and interested citizens to help
make these decisions. And citizens should make themselves heard.
EPA had to decide what degree of air quality deterioration
would be considered "significant." In areas having very clean
air, it was not possible to set standards based on any measure-
ments of damage to the public health or welfare. On the other
hand, it was the intent of the 1970 law to prevent the air every-
where from becoming uniformly dirty through a "leveling out" of
the Nation's air pollution.
The EPA regulations seek to define "significant" in a
reasonable way that will allow both for protection of clean
areas and for national economic growth. Any growth that occurs
will be well planned, orderly and with application of best
available control technology to keep the air as clean as possible.
Overall, the regulations will result in much more stringent
limitations on pollution than would be the case if no such rules
exi sted.
WILL THIS MEAN THAT ALL ECONOMIC GROWTH WILL STOP?
Not at all. The air pollution limit for a Class II
area, for example, would under normal circumstances permit
construction there of any of the major source categories that
will be regulated in the program to prevent significant
deterioration.
In a Class III area, an aggregation of major industrial
projects may be constructed as long as air quality standards
are not exceeded.
The program thus can help States and local governments
-------
-5-
and citizens decide not only where growth should be prohibited,
but also where growth should be encouraged.
DOES THIS PROGRAM MEAN MORE FEDERAL CONTROL?
No. The program gives the States and local governments
the flexibility and primary responsibility for making decisions
that affect the people they serve. State and local people have
a better understanding of the social, economic and environ-
mental factors that go into decisions to reclassify. State
and local governments can be more responsive to State and local
needs than any Federal agency. Moreover, EPA believes that
State and local governments should continue to exercise the
basic land-use decision-making responsibility.
CAN A CLEAN AREA PROTECT ITSELF?
That's up to local governments and the State, mainly.
Even a slight increase in pollution in the air might damage
the economy of a recreational area. On the other !iand, an
area facing severe unemployment may welcome industrial growth
and new job opportunities. Even in the latter cas , however,
air quality impact can and should be minimized.
EPA believes that most decisions about development of
affected areas should not be based only on environmental factors
For this reason, as long as proper procedures are followed and
no decision is arbitrary or capricious, EPA wants the States
or local governments and the people to make decisions about
whether to reclassify an area to Class I (no development) or
Class III (whatever development the air quality standard will
allow).
REGIONAL AND NATIONAL EFFECTS OF RECLASSIFICATION
An example of a "regional" effect would be the downwind
impact of air pollution' from a power plant. Where a major
industrial source is planned, the facility must be situated
so it will not affect air quality in "adjacent" areas--
perhaps up to a distance of 60 miles in the case of a coal-
fired power plant of 1,000 or more megawatts controlling
emissions to meet new source performance standards. For
other major sources, and for power plants controlling emissions
beyond new source performance standards, downwind effect
generally will be considerably less — perhaps 6 to 30 miles.
Such variables as the terrain, weather conditions, and the
size of the source would be determining factors.
"National" effects might include such elements as the
impact of pollution on food supply and production, the pre-
servation of sufficient recreation and wilderness land, and
the supply and development of energy resources.
-------
-6-
After a State's proposed redesignation of an area to
Class I or III is offered for public comment in the Federal
Register, Federal agencies and any citizen would be expected
to make known their views on any national effects of which
they are aware. Finally, it would be up to the Administrator
of EPA to rule on the proposed request.
WON'T EVERYONE BE TRYING TO SWITCH TO CLASS I OR III?
EPA believes not. No large-scale switching of classifications
is expected because Class II--into which all areas now fall--
will accommodate most moderate, well planned development while
also providing substantial safeguards for air quality. And the
public can be expected to react against efforts either to
unreasonably restrain development or to endanger valued areas
that should be preserved.
January 1976
------- |