National Ambient Standands | Louisiana Department of Environmental Quality
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National Ambient Standands
Air Quality Standards
Use the following table to access information about the individual standards as well as the attainment status and ongoing efforts surrounding each pollutant.
Criteria Pollutant
Primary/ Secondary
Averaging Time
Level
Form
Attainment Status
Carbon Monoxide
Primary
8-hour
1-hour
9ppm
35ppm
Not to be exceeded more than once per year
Attainment
Lead
Primary and Secondary
Rolling 3-month average
0.15 µg/m3 (1)
Not to be exceeded
Attainment
Nitrogen Dioxide
Primary
Primary and Secondary
1-hour
Annual
100 ppb
53 ppb (2)
98th percentile, averaged over 3 years
Annual Mean
Attainment
Ozone
Primary and Secondary
8-hour
0.070 ppm (3)
Annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years
Attainment
Particle Pollution PM2.5
Primary and Secondary
Annual
24-hour
12 µg/m3
35 µg/m3
Annual mean, averaged over 3 years
98th percentile, averaged over 3 years
Attainment
Particle Pollution PM10
Primary and Secondary
24-hour
150 µg/m3
Not to be exceeded more than once per year on average over 3 years
Attainment
Sulfur Dioxide
Primary
Secondary
1-hour
3-hour
75 ppb (4)
0.5 ppm
99th percentile of 1-hour daily maximum concentrations, averaged over 3 years
Not to be exceeded more than once per year
Non-Attainment for St. Bernard Parish
(1) Final rule signed October 15, 2008. The 1978 lead standard (1.5 µg/m3 as a quarterly average) remains in effect until one year after an area is designated for the 2008 standard, except that in areas designated nonattainment for the 1978, the 1978 standard remains in effect until implementation plans to attain or maintain the 2008 standard are approved.
(2) The official level of the annual NO2 standard is 0.053 ppm, equal to 53 ppb, which is shown here for the purpose of clearer comparison to the 1-hour standard.
(3) Final rule signed March 12, 2008. The 1997 ozone standard (0.08 ppm, annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years) and related implementation rules remain in place. In 1997, EPA revoked the 1-hour ozone standard (0.12 ppm, not to be exceeded more than once per year) in all areas, although some areas have continued obligations under that standard (“anti-backsliding”). The 1-hour ozone standard is attained when the expected number of days per calendar year with maximum hourly average concentrations above 0.12 ppm is less than or equal to 1.
(4) Final rule signed June 2, 2010. The 1971 annual and 24-hour SO2 standards were revoked in that same rulemaking. However, these standards remain in effect until one year after an area is designated for the 2010 standard, except in areas designated nonattainment for the 1971 standards, where the 1971 standards remain in effect until implementation plans to attain or maintain the 2010 standard are approved.
Ozone Pollution and Prevention
Baton Rouge Ozone Attainment Efforts
Ozone Related Links on EPA Website
Sulfur Dioxide Standard
On June 22, 2010, EPA promulgated a revised 1-hour, 75 ppm, sulfur oxide (SO2) primary standard. The SO2 primary standard was revised to provide requisite protection of public health. Under Section 110 (a) of the Federal Clean Air Act, States after promulgation of a national primary ambient air quality standard (or any revision thereof), must implement plans to attain or maintain the standard. The State Implementation Plan (SIP) must demonstrate, through refined air quality modeling, that all sources contributing to or having the potential to contribute to monitored and modeled violations will be sufficiently controlled to ensure timely attainment and maintenance of the new SO2 standard.
The primary SO2 final rule (1) replaces the 24-hour and annual standard, (2) establishes a new 1-hour standard (3) utilizes the 3-year average of the 4thhighest daily maximum 1-hour concentration, (4) establishes new requirements for the SO2 monitoring network, and (5) finalizes conforming changes to the Air Quality Index (AQI).
