New National Ambient Air Quality Standard
For Ground-level Ozone

Air Quality

Air Quality Forecast & Agricultural Burn Status

Air Quality Index

Air Quality Standards

Air Quality Statistics

EPA’s New Standard for Ground-level Ozone

On March 12, 2008, the U.S. Environmental Protection Agency (EPA) strengthened the National Ambient Air Quality Standard (NAAQS) for ground-level ozone. Specifically, EPA revised the primary and secondary 8-hour ozone standards to 0.075 parts per million (ppm). The previous standard was 0.08 ppm. EPA last revised the ozone NAAQS in 1997. At that time, the primary and secondary 8-hour ozone standards were set at 0.08 ppm (effectively 0.084 due to rounding). For now, the 1997 ozone NAAQS and all the associated regulatory requirements will remain in place; state and local air agencies will continue implementing their plans for the 1997 ozone NAAQS.

 

By 2010 EPA will designate areas in the country that do not attain the new ozone NAAQS. Those areas will have three years to develop attainment plans to show how they will attain the new ozone standard.

 

Depending upon the severity of their ozone problem, non-attainment areas will have until the year 2030 to attain the new ozone NAAQS.

 

EPA estimates that there are 345 monitored counties in the country that currently violate the new ozone NAAQS, and that 28 counties are projected to violate the standard in 2020.

 

Along with EPA’s action to strengthen the ozone NAAQS, EPA also revised the Air Quality Index (AQI) for ozone to reflect the more stringent new standard. The AQI is a color-coded tool designed to inform the public about daily air pollution levels in the communities.

 

Category

AQI Value

1997
8-hour (ppm)

2008
8-hour (ppm)

GOOD

0-50

0.000-0.064

0.000-0.059

MODERATE

51-100

0.065-0.084

0.060-0.075

UNHEALTHY FOR
SENSITIVE GROUPS

101-150

0.085-0.104

0.076-0.095

UNHEALTHY

151-200

0.105-0.124

0.096-0.115

VERY UNHEALTHY

201-300

0-125-0.374

0.116-0.374

 

As part of the Ventura County APCD’s mission to monitor the County’s air quality and provide timely information to the public, the APCD forecasts the County’s ozone air quality on a daily basis and uses the AQI to inform the public of the County’s air quality. Click here to see the air quality forecast for Ventura County.

 

How does this change affect Ventura County?

Ventura County has been designated by EPA as a “moderate” non-attainment area for the 1997 0.08 ppm ozone NAAQS. EPA predicts that Ventura County is one of the 28 counties that will not be able to attain the new ozone standard by the year 2020.

 

As of March 13, 2008, the APCD began reporting the County’s ozone levels using the new ozone Air Quality Index. The use of the new AQI is more protective of the public’s health and will result in more days being shown with an increased AQI.

 

For more information:

EPA's website announcing the new ozone standards is:

http://www.epa.gov/groundlevelozone/actions.html#mar07s

 

Click on the link below view an EPA slide presentation on the new ozone standard.

http://www.epa.gov/groundlevelozone/pdfs/2008_03_text_slides.pdf

 

Click on the link below to see a map of counties with monitors violating the 2008 8-hour ozone standard of 0.075 ppm.

http://www.epa.gov/groundlevelozone/pdfs/2008_03_monitors_violating_2008.pdf

 

Click on the link below to see a map of counties with monitors projected to violate the 2008 8-hour ozone standard of 0.075 ppm in 2020.

http://www.epa.gov/groundlevelozone/pdfs/2008_03_monitors_projected_violate_2020.pdf