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Table of Historical Ozone NAAQS
History of the National Ambient Air Quality Standards for Ozone
During the Period 1971-2008
Final
Rule/Decision
Primary/
Secondary
Indicator
Primary and
Secondary
Total
photochemical
oxidants
1971
Nitrogen Dioxide
Secondary Standards
36 FR 8186
Apr 30, 1971
(1)
Averaging
Time
1-hour
Level
Ozone Implementation
44 FR 8202
Feb 8, 1979
Particulate Matter
Standards
Primary and
Secondary
O3
1-hour
Form
(2)
0.08
ppm
Not to be exceeded more
than one hour per year
0.12
ppm
Attainment is defined when
the expected number of
days per calendar year,
with maximum hourly
average concentration
greater than 0.12 ppm, is
equal to or less than 1
1979
Ozone Standards
1993
PM Implementation
58 FR 13008
Mar 9, 1993
1997
Sulfur Dioxide Primary
Standards
Sulfur Dioxide
Secondary Standards
Sulfur Dioxide
Implementation
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Ozone (O3) Standards -
Lead Implementation
Nitrogen Dioxide
Implementation
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Nitrogen Dioxide
Primary Standards
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62 FR 38856
Jul 18, 1997
2008
73 FR 16483
Mar 27, 2008
EPA decided that revisions to the standards were not warranted at the time
Primary and
Secondary
O3
8-hour
Primary and
Secondary
O3
8-hour
(1)
O3 = ozone
(2)
Units of measure are in parts per million (ppm).
Annual fourth-highest daily
maximum 8-hr
concentration, averaged
over 3 years
Annual fourth-highest daily
0.075 maximum 8-hr
ppm concentration, averaged
over 3 years
0.08
ppm
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Last updated on Tuesday, June 11, 2013
http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_history.html
2/4/2015