[Code of Federal Regulations]
[Title 40, Volume 5]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR58.1]

[Page 205-208]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 58--AMBIENT AIR QUALITY SURVEILLANCE--Table of Contents
 
                      Subpart A--General Provisions
 
Sec. 58.1  Definitions.


    As used in this part, all terms not defined herein have the meaning 
given them in the Act:
    Act means the Clean Air Act as amended (42 U.S.C. 7401, et seq.).
    Administrator means the Administrator of the Environmental 
Protection Agency (EPA) or his or her authorized representative.
    Aerometric Information Retrieval System (AIRS)-Air Quality Subsystem 
(AQS) is EPA's computerized system for storing and reporting of 
information relating to ambient air quality data.
    Annual State air monitoring report is an annual report, prepared by 
control agencies and submitted to EPA for approval, that consists of an 
annual data summary report for all pollutants and a detailed report 
describing any proposed changes to their air quality surveillance 
network.
    CO means carbon monoxide.
    Community Monitoring Zone (CMZ) means an optional averaging area 
with established, well defined boundaries, such as county or census 
block, within a MPA that has relatively uniform concentrations of annual 
PM2.5 as defined by appendix D of this part. Two or more core 
SLAMS and other monitors within a CMZ that meet certain requirements as 
set forth in Appendix D of this part may be averaged for making 
comparisons to the annual PM2.5 NAAQS.
    Consolidated Metropolitan Statistical Area (CMSA) means the most 
recent area as designated by the U.S. Office of Management and Budget 
and population figures from the Bureau of the Census. The Department of 
Commerce provides that within metropolitan complexes of 1 million or 
more population, separate component areas are defined if specific 
criteria are met. Such areas are designated primary metropolitan 
statistical areas (PMSAs; and any area containing PMSAs is designated 
CMSA.

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    Core PM2.5 SLAMS means community-oriented monitoring 
sites representative of community-wide exposures that are the basic 
component sites of the PM2.5 SLAMS regulatory network. Core 
PM2.5 SLAMS include community-oriented SLAMS monitors, and 
sites collocated at PAMS.
    Corrected concentration pertains to the result of an accuracy or 
precision assessment test of an open path analyzer in which a high-
concentration test or audit standard gas contained in a short test cell 
is inserted into the optical measurement beam of the instrument. When 
the pollutant concentration measured by the analyzer in such a test 
includes both the pollutant concentration in the test cell and the 
concentration in the atmosphere, the atmospheric pollutant concentration 
must be subtracted from the test measurement to obtain the corrected 
concentration test result. The corrected concentration is equal to the 
measured concentration minus the average of the atmospheric pollutant 
concentrations measured (without the test cell) immediately before and 
immediately after the test.
    Correlated acceptable continuous (CAC) PM analyzer means an optional 
fine particulate matter analyzer that can be used to supplement a 
PM2.5 reference or equivalent sampler, in accordance with the 
provisions of Sec. 58.13(f).
    Effective concentration pertains to testing an open path analyzer 
with a high-concentration calibration or audit standard gas contained in 
a short test cell inserted into the optical measurement beam of the 
instrument. Effective concentration is the equivalent ambient-level 
concentration that would produce the same spectral absorbance over the 
actual atmospheric monitoring path length as produced by the high-
concentration gas in the short test cell. Quantitatively, effective 
concentration is equal to the actual concentration of the gas standard 
in the test cell multiplied by the ratio of the path length of the test 
cell to the actual atmospheric monitoring path length.
    Equivalent method means a method of sampling and analyzing the 
ambient air for an air pollutant that has been designated as an 
equivalent method in accordance with part 53 of this chapter; it does 
not include a method for which an equivalent method designation has been 
canceled in accordance with Sec. 53.11 or Sec. 53.16 of this chapter.
    Indian Governing Body means the governing body of any tribe, band, 
or group of Indians subject to the jurisdiction of the United States and 
recognized by the United States as possessing power of self-government.
    Indian Reservation means any Federally recognized reservation 
established by treaty, agreement, executive order, or act of Congress.
    Local agency means any local government agency, other than the State 
agency, which is charged with the responsibility for carrying out a 
portion of the plan.
    Meteorological measurements means measurements of wind speed, wind 
direction, barometric pressure, temperature, relative humidity, and 
solar radiation.
    Metropolitan Statistical Area (MSA) as designated by the most recent 
decennial U.S. Census of Population Report.
    Monitor is a generic term for an instrument, sampler, analyzer, or 
other device that measures or assists in the measurement of atmospheric 
air pollutants and which is acceptable for use in ambient air 
surveillance under the provisions of appendix C to this part, including 
both point and open path analyzers that have been designated as either 
reference or equivalent methods under part 53 of this chapter and air 
samplers that are specified as part of a manual method that has been 
designated as a reference or equivalent method under part 53 of this 
chapter.
    Monitoring path for an open path analyzer is the actual path in 
space between two geographical locations over which the pollutant 
concentration is measured and averaged.
    Monitoring path length of an open path analyzer is the length of the 
monitoring path in the atmosphere over which the average pollutant 
concentration measurement (path-averaged concentration) is determined. 
See also, optical measurement path length.
    Monitoring Planning Area (MPA) means a contiguous geographic area

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with established, well defined boundaries, such as a metropolitan 
statistical area, county or State, having a common area that is used for 
planning monitoring locations for PM2.5. MPAs may cross State 
boundaries, such as the Philadelphia PA-NJ MSA, and be further 
subdivided into community monitoring zones. MPAs are generally oriented 
toward areas with populations greater than 200,000, but for convenience, 
those portions of a State that are not associated with MSAs can be 
considered as a single MPA. MPAs must be defined, where applicable, in a 
State PM monitoring network description.
    NAMS means National Air Monitoring Station(s). Collectively the NAMS 
are a subset of the SLAMS ambient air quality monitoring network.
    NO2 means nitrogen dioxide. NO means nitrogen oxide. 
NOX means oxides of nitrogen and is defined as the sum of the 
concentrations of NO2 and NO.
    O3 means ozone.
    Open path analyzer is an automated analytical method that measures 
the average atmospheric pollutant concentration in situ along one or 
more monitoring paths having a monitoring path length of 5 meters or 
more and that has been designated as a reference or equivalent method 
under the provisions of part 53 of this chapter.
    Optical measurement path length is the actual length of the optical 
beam over which measurement of the pollutant is determined. The path-
integrated pollutant concentration measured by the analyzer is divided 
by the optical measurement path length to determine the path-averaged 
concentration. Generally, the optical measurement path length is:
    (1) Equal to the monitoring path length for a (bistatic) system 
having a transmitter and a receiver at opposite ends of the monitoring 
path;
    (2) Equal to twice the monitoring path length for a (monostatic) 
system having a transmitter and receiver at one end of the monitoring 
path and a mirror or retroreflector at the other end; or
    (3) Equal to some multiple of the monitoring path length for more 
complex systems having multiple passes of the measurement beam through 
the monitoring path.
    PAMS means Photochemical Assessment Monitoring Stations.
    Particulate matter monitoring network description, required by 
Sec. 58.20(f), means a detailed plan, prepared by control agencies and 
submitted to EPA for approval, that describes their PM2.5 and 
PM10 air quality surveillance network.
    Pb means lead.
    Plan means an implementation plan, approved or promulgated pursuant 
to section 110 of the Clean Air Act.
    PM2.5 means particulate matter with an aerodynamic 
diameter less than or equal to a nominal 2.5 micrometers as measured by 
a reference method based on 40 CFR part 50, Appendix L, and designated 
in accordance with part 53 of this chapter or by an equivalent method 
designated in accordance with part 53 of this chapter.
    PM10 means particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers as measured by a 
reference method based on appendix J of part 50 of this chapter and 
designated in accordance with part 53 of this chapter or by an 
equivalent method designated in accordance with part 53 of this chapter.
    Point analyzer is an automated analytical method that measures 
pollutant concentration in an ambient air sample extracted from the 
atmosphere at a specific inlet probe point and that has been designated 
as a reference or equivalent method in accordance with part 53 of this 
chapter.
    Population-oriented monitoring (or sites) applies to residential 
areas, commercial areas, recreational areas, industrial areas, and other 
areas where a substantial number of people may spend a significant 
fraction of their day.
    Primary Metropolitan Statistical Area (PMSA) is a separate component 
of a consolidated metropolitan statistical area. For the purposes of 
this part, PMSA is used interchangeably with MSA.
    Probe is the actual inlet where an air sample is extracted from the 
atmosphere for delivery to a sampler or point analyzer for pollutant 
analysis.
    PSD station means any station operated for the purpose of 
establishing the

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effect on air quality of the emissions from a proposed source for 
purposes of prevention of significant deterioration as required by 
Sec. 51.24(n) of part 51 of this chapter.
    Reference method means a method of sampling and analyzing the 
ambient air for an air pollutant that will be specified as a reference 
method in an appendix to part 50 of this chapter, or a method that has 
been designated as a reference method in accordance with this part; it 
does not include a method for which a reference method designation has 
been canceled in accordance with Sec. 53.11 or Sec. 53.16 of this 
chapter.
    Regional Administrator means the Administrator of one of the ten EPA 
Regional Offices or his or her authorized representative.
    SAROAD site identification form is one of the several forms in the 
SAROAD system. It is the form which provides a complete description of 
the site (and its surroundings) of an ambient air quality monitoring 
station.
    SLAMS means State or Local Air Monitoring Station(s). The SLAMS make 
up the ambient air quality monitoring network which is required by 
Sec. 58.20 to be provided for in the State's implementation plan. This 
definition places no restrictions on the use of the physical structure 
or facility housing the SLAMS. Any combination of SLAMS and any other 
monitors (Special Purpose, NAMS, PSD) may occupy the same facility or 
structure without affecting the respective definitions of those 
monitoring station.
    SO2 means sulfur dioxide.
    Special Purpose Monitor (SPM) is a generic term used for all 
monitors other than SLAMS, NAMS, PAMS, and PSD monitors included in an 
agency's monitoring network for monitors used in a special study whose 
data are officially reported to EPA.
    State agency means the air pollution control agency primarily 
responsible for development and implementation of a plan under the Act.
    Storage and Retrieval of Aerometric Data (SAROAD) system is a 
computerized system which stores and reports information relating to 
ambient air quality. The SAROAD system has been replaced with the AIRS-
AQS system; however, the SAROAD data reporting format continues to be 
used by some States and local air pollution agencies as an interface to 
AIRS on an interim basis.
    Traceable means that a local standard has been compared and 
certified, either directly or via not more than one intermediate 
standard, to a National Institute of Standards and Technology (NIST)-
certified primary standard such as a NIST-Traceable Reference Material 
(NTRM) or a NIST-certified Gas Manufacturer's Internal Standard (GMIS).
    TSP (total suspended particulates) means particulate matter as 
measured by the method described in appendix B of part 50 of this 
chapter,
    Urban area population means the population defined in the most 
recent decennial U.S. Census of Population Report.
    VOC means volatile organic compounds.

[44 FR 27571, May 10, 1979, as amended at 48 FR 2529, Jan. 20, 1983; 51 
FR 9586, Mar. 19, 1986; 52 FR 24739, July 1, 1987; 58 FR 8467, Feb. 12, 
1993; 59 FR 41628, 41629, Aug. 12, 1994; 60 FR 52319, Oct. 6, 1995; 62 
FR 38830, July 18, 1997; 63 FR 7714, Feb. 17, 1998]