Encyclopedia of Environmental Science and Engineering, Volume I and II

72 AIR POLLUTION SOURCES

pollutants (nitrogen dioxide, sulfur dioxide, hydrocarbons,

carbon monoxide, particulate matter and ozone) were identi-

fied in 1971 as the most “universal” within the United States

and the most significant pollutants contributing to the degra-

dation of the lower atmosphere or troposphere. Once national

air quality standards were established each state was given

the responsibility to make sure that emissions from sources of

air pollution in that state and neighboring states do not violate

these air quality standards by developing and implementing

creative plans for reducing source emissions. Recognizing

that hydrocarbons in the atmosphere did not, as a class of

pollutants, create a singular and internally consistent ambient

air quality problem, the class term was dropped and lead was

added as a new pollutant class.

Hazardous Pollutants These are air pollutants for which

no air quality standard has been established but nevertheless

cause or contribute to an increase in the mortality rate or

serious irreversible or incapacitating illness. The hazardous

pollutants listed by January 1988 are: asbestos, beryllium,

mercury, vinyl chloride, radionuclides, coke oven emissions,

benzene and inorganic arsenic.

In November of 1990, the U.S. Congress passed Clean

Air Act amendments (CAAA) into law which greatly expand

the list of regulated chemicals—Hazardous Air Pollutants

(HAPs)– to about 190. The EPA’s mandate is to promulgate

standards for the control of HAP emissions from about 100

source categories, employing maximum achievable control

technology (MACT). To date greater than 95% of MACT

standards have been published.

Source: http://www.epa.gov/ttn/atw/eparules.html

SOURCE CLASSIFICATIONS

The management and control of air pollution is generally

achieved through the regulation and control of air pollution

sources. For convenience, sources of air pollutants may be

classified according to the size or the nature of the pollutant

activity and source type characteristics.

Classification According to Magnitude

For convenience of analysis, air pollution sources are divided

into two classes (1) major sources and (2) minor sources.

Major sources are sources whose emissions quantities

are large enough to cause them to have a dominant role in the

pollution potential of an area. Prior to the 1990 CAAA, the

U.S. Environmental Protection Agency classified all sources

that emitted or had the potential for emitting 100 tons/year

of any single pollutant as a major source.

Today, the definition has been revised and made more

stringent. Depending upon an area’s air quality, emissions of

as little as 10 tons/year would constitute a major source.

Major sources are fixed (stationary) and commonly

occupy a limited area relative to a community. They include:

1. Major industrial and manufacturing plants.


2. Steam—Electric power plants.
   3. Industrial and Municipal Incinerators.
   4. Facilities that use solvents (surface coating,
   degreasing, dry cleaning, plastics manufacture,
   rubber manufacture) and lose petroleum products
   by evaporation.
   5. Facilities that lose petroleum product from stor-
   age and marketing (tank farms, service stations)
   operations.
   6. Motor vehicles, aircraft, ships and railroads in which
   the combustion of fuels for transportation occurs.
   7. Dumps, incinerators, etc. in which combustion of
   wastes occur.
   8. Facilities or units in which the decomposition of
   organic wastes occur.
   9. Sewage treatment plants.

Industrial plants constitute a highly varied and complex

chemical system, each industry presenting a unique air pollu-

tion problem. The characteristics of the emissions produced

are directly related to the peculiarities of the operation in

question, that is, on the raw materials, the fuels, the process

method, the efficiency of the chosen process, the method and

the type of air pollution control measures applied.

Minor sources are those which cannot be cataloged prac-

tically on a source-by-source basis. They may be stationary

or mobile and are commonly spread throughout the commu-

nity. These sources are associated with:

1. Combustion of fuels in residences and commer-
   cial buildings and institutions for personal com-
   fort and convenience.


2. Service industries such as laundries, dry-cleaning
   plants, repair services, etc.


3. Animal processing.


4. Handling and use of paints, lacquers and other
   surface coatings containing organic solvents.


5. Food processing in restaurants, grills, coffee
   roasting, etc.

Classification According to Nature of Emissions

The U.S. Environmental Protection Agency classifies sources

depending on both the quantitative and qualitative nature of

the emissions. The source categories are:

1. NSPS (New Source Performance Standard) sources.
   These are sources for which national emissions
   standards have been established. All sources built
   subsequent to the date of establishment of these
   emissions standards must meet NSPS requirements.


2. SIP (State Implementation Plan) sources. These
   are sources built prior to the establishment of the
   new source standards. These older SIP sources
   have no national emissions standards to follow per
   se, but rather their level of emissions is determined
   on a source-by-source basis and depend on the air
   quality of the area in which they are located. If the

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