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NAVIGATING THE CLEAN AIR ACT
Since it was reauthorized six years ago, the Clean Air Act (CAA)
has generated an extraordinary amount of regulatory activity by both
EPA and the states. The programs these agencies are implementing
are often complex and as such it may be helpful to step back for
a moment and look at the overall framework established to improve
air quality in the United States.
Title I -- Urban Air
Title I of the CAA contains general statements of policy, authorizes
financial assistance to states, and establishes a framework for
national ambient air quality standards for six so-called "criteria" pollutants,
including ozone. VOCs are regulated under the criteria pollutants
program as ozone precursors.
Title II -- Motor Vehicles
This section of the CAA establishes emission control programs for
automobiles, trucks, and airplanes. EPA is also empowered to
target facilities and areas that attract mobil sources of pollution.
Title III -- Air Toxics
In Title III, Congress established a list of 189 hazardous air
pollutants or "HAPs." EPA is required to establish
technology-based standards for industry sources of HAPs. Once
these standards are in place, EPA must conduct a "residual
risk" evaluation of their effectiveness in controlling emissions
to determine if additional regulation is needed. This section
also covers general administrative provisions, citizens suits,
and judicial review of EPA CAA rules.
Title IV -- Acid Rain
Congress established a program to allow sulfur dioxide emissions
to be allocated and traded. In addition, nitrogen oxide emission
limitations are required for certain coal-fired electric utility
units. Industries most affected are those that burn coal or oil
or otherwise emit substantial quantities of these pollutants.
Title V -- Operating Permits
The minimum elements of state operating permit programs are contained
in Title V. Major sources must obtain an operating permit that
addresses all pollution control obligations. Sources must also
file periodic reports on the extent of their compliance.
Title VI -- Stratospheric Ozone
To address global warming, Title VI authorizes EPA to establish
labeling requirements for products manufactured with ozone-depleting
substances and products containing such substances. EPA is authorized
consistent with the Montreal Protocol to phase-out ozone-depleting
compounds.
GLOSSARY OF KEY AIR POLLUTION CONTROL TERMS
| Area Source |
Any stationary source of hazardous
air pollutants that is not a major source. Attainment Area
An area considered to have air quality as good or better
than the NAAQS. |
| BACT |
Best Available Control Technology
is the technology required pursuant to § 165 on new
major sources and major modification subject to PSD requirements
(sources located in attainment areas), which reflect the
best control in use taking into account costs. PSD, or Prevention
of Significant Deterioration, is a program established under
Title I of the Clean Air Act to preserve air quality in areas
already meeting the National Ambient Air Quality Standards
(NAAQS). |
| Criteria Pollutants |
Emissions which are subject to National
Ambient Air Quality standards (NAAQS). They are: lead (Pb);
oxides of nitrogen (NOx); sulfur dioxide (SO2); ozone; carbon
monoxide (CO); and small particulates (PM-10). |
| CTGs |
Control Technique Guidelines. EPA's
method of applying the RACT concept to specified industrial
categories in nonattainment areas; they contain information
both on the economic and technological feasibility of available
techniques. CTGs will be expanded and revised by EPA in the
near future. |
| FIP |
Federal Implementation Plan. Plans
promulgated by EPA if states fail to develop approvable SIPs. |
| Fugitive Emissions |
Emissions not caught by an emission
control or capture system. |
| HAPs |
Hazardous Air Pollutants. One of
189 air pollutants listed in CAA § 112. Many of these
substances are also VOCs. |
| LAER |
Lowest Achievable Emissions Rate
is the degree of control required pursuant to § 173
of the Clean Air Act on new major sources and major modifications
in nonattainment areas; the technology must be in use or
most stringent in any SIP (does not take into account cost).
LAER is the most stringent emission limitation among control
technologies. |
| MACT |
Maximum Achievable Control Technology
(MACT). The maximum degree of reduction that is achievable
through capture, treatment, process changes, substitution
of materials and work practices, and taking into account
costs and benefits. MACT may be varied depending on whether
the source is a new, existing, or area source. |
| Major Source |
(also "Major Stationary Source")
The definition varies depending upon the level of attainment
for a particular pollutant in the area in which the plant
is located. For example, in severe ozone nonattainment areas,
a major source will be one that emits more than twenty-five
tons of ozone precursors. For hazardous pollutants, a major
source is an industrial facility which emits 10 tons per
year of any single air toxic on 25 tons per year of any combination
of air toxics. |
| NAAQS |
National Ambient Air Quality Standards.
Maximum allowable concentrations of pollutants which represent
goals for desirable air quality for human health (primary
standards) and agricultural, production, and aesthetic purposes
(secondary standards). EPA sets these standards for each
criteria pollutant. |
| NESHAP |
National Emissions Standards for
Hazardous Air Pollutants. Program established under CAA § 112
to regulate HAPs. |
| Nonattainment |
Failure to meet the NAAQS for a
criteria pollutant in a particular AQCR. In 1977, Congress
divided all areas of the country into two categories: those
that failed to meet NAAQS (i.e., nonattainment areas) and
PSD areas. Nonattainment areas are further categorized as "extreme," "severe," "moderate," or "marginal." The
more polluted the area, the more stringent the restrictions. |
| NSR |
New Source Review. Program for pre-construction
review of new major sources and major modifications under
PSD and Nonattainment requirements. |
| NSPS |
New Source Performance Standards.
Emission limitations for stationary sources in particular
industrial categories. NSPS target specific pollutants from
specified industries, rather than air quality in general. |
| Ozone Smog |
Ozone is not a pollutant emitted
directly into the atmosphere but rather is the product of
a complex series of chemical reactions initiated when VOCs
and NOx emissions are exposed to sunlight. It should not
be confused with the layer of ozone in the upper atmosphere
(stratospheric ozone) which shields the sun's harmful ultraviolet
radiation. Permit Program The air emissions source operating
permit program established under CAA Title V. |
| PM-10 |
The regulatory identifier for all
types of airborne particulate matter with a diameter of less
than 10 microns. Smaller particles are more likely to cause
adverse health effects because of their ability to penetrate
the body's natural defenses. |
| Potential To Emit |
The maximum capacity of a source
to emit any air pollutant under its physical and operational
design. Any physical or operational limitation on the capacity
of a source to emit an air pollutant, including air pollution
control equipment, restrictions on the hours of operations,
or on the type or amount of material combusted, stored or
processed shall be considered if the limitation is federally
enforceable. |
| PSD |
Prevention of Significant Deterioration.
Generally refers to one of the two programs Congress created
in 1977 (the other being the nonattainment program). The
PSD program is designed to avoid degradation of air quality
in areas of the country with satisfactory air quality. |
| RACT |
Reasonably Available Control Technology
is the technology required for existing major source in nonattainment
areas. RACT typically reflects controls the EPA has identified
in Control Technique Guidelines (CTG) or other guidance.
SIPs must be revised to required RACT for control of VOC
emissions from sources for which EPA has published (or will
publish) a CTG. |
| SIP |
State Implementation Plan. A state-specific
plan for ensuring that all nonattainment areas within a state
meet ambient air quality standards (NAAQS) and for avoiding
degradation of air quality in PSD areas within the statutory
deadline. |
| Synthetic Minor Sources |
Sources that would otherwise be
classified as "major sources" based on their "potential to
emit" but avoid classification as a major source by agreeing
to observe an emission limit below the applicable major source
threshold. The emission limit must be physical or operational
and must be federally enforceable. |
| VOCs |
Volatile Organic Compounds. A general
term for a wide range of hydrocarbons which come from combustion
processes, gasoline vapors, solvents, etc. With NOx and sunlight,
VOCs react to form ozone. |
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