Ozone Action Days

Ozone Action Days

Air Division
Planning & Air Quality Analysis Branch

Tony Davis, Branch Manager - (501) 682-0728

Ozone Action Days

"Air Quality is a Priority in the Natural State"

Throughout the May through September "Ozone Season", ozone forecasts for the Little Rock/North Little Rock Metropolitan Statistical Area (MSA) are conducted on a daily basis. This MSA area includes Pulaski, Saline, Faulkner, and Lonoke Counties.

For air quality information throughout the entire year the ADEQ Air Quality Index (AQI), a measure of overall air quality that identifies the most significant air pollutant for the day, is reported by ADEQ's Technical Services Division on weekdays.

Air quality is variable and dependent upon a number of factors including; sunlight, temperature, wind speed and direction. Like the weather, it can change from day to day or even hour to hour. The U.S. Environmental Protection Agency (EPA) and others are working to make local air quality information as available to the public as weather information. Ozone Action Days is our local central Arkansas program coordinated through Metroplan and the Central Arkansas Clean Cities Coalition in cooperation with the Arkansas Department of Health (ADH), Arkansas Department of Environmental Quality (ADEQ), and the Arkansas Highway and Transportation Department (AHTD). Counties included in the program are Pulaski, Faulkner, Lonoke and Saline.

Air pollution affects everyone. Every day, the average adult breathes over 3,000 gallons of air. Children breathe even more air per pound of body weight and are thus more susceptible to air pollution. Children are even at a greater risk than adults because they are more active outdoors and their lungs are still developing. The elderly are more sensitive than healthy adults to air pollution because senior citizens often have heart or lung disease. When people have a short-term exposure to air pollutants above certain levels, they may experience temporary health concerns, such as eye irritation and burning, throat irritation, and difficulty breathing. Long-term exposure to air pollution can cause chronic health concerns, such as cancer and damage to the body's immune, neurological, reproductive, and respiratory systems.

Since the inception of the Ozone Action Days program in 1998, the participating agencies have worked to increase public awareness of ozone related health risks and ways to reduce ozone precursor emissions. "Ozone Action Alerts" are declared when ozone forecasts have indicated the next day’s conditions could support the formation of high concentrations of ground level ozone. The Ozone Action Days program emphasis is on providing notification about the predicted high ozone episodes with suggestions for voluntary actions to protect public health, especially those populations identified as most at risk and ways in which individuals and groups can work to reduce the production of nitrogen oxides and volatile organic compounds released into our air.

The air quality professionals of the ADEQ Air Division Planning and Air Quality Analysis Branch create the daily ozone forecast. Several external resources and tools are used in support of these forecasts. Little Rock’s National Weather Service Forecast Office provides current meteorological condition and next day meteorological forecasts that provide valuable input into decision trees and statistical analysis processes.  Ozone monitors throughout the state provide the real-time ozone data for use in forecasting and also supply the data to produce AIRNow’s animated ozone maps.  Please access the daily ozone forecast and incorporate the health protection recommendations into your plans for the following day. Remember that ozone forecasting is a prediction of tomorrow’s ground level ozone concentrations. While the ozone forecasters do their best to be as accurate as possible, because it is a prediction, occasionally they are incorrect.

As of Ozone Season 2000, ozone forecasts for the Little Rock/North Little Rock MSA have been posted on ADEQ’s website and EPA’s AIRNow website each day from May through September. Arkansas’ Ozone Action Days program and 165 other cities across the United States use the format of EPA's Air Quality Index (AQI) to clearly display predicted ozone levels. The AQI format focuses on the health effects of breathing polluted air. The AQI is like a yardstick that runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and health risk. A specific color has been assigned to each AQI category to make it easier for people to quickly understand the significance of air pollution levels. By 3:00 p.m., the daily ozone forecast is posted on this Web page.

Ozone Action Day Alerts and Advisories are issued when ground-level ozone concentrations in the Little Rock/North Little Rock MSA are forecast to be in exceedance of the National Ambient Air Quality Standards (NAAQS).  http://www.epa.gov/ttn/naaqs/ has more information about the NAAQS. The predicted Air Quality Index on these days will be in the unhealthy range. Fax or email notification will be provided to local news media, employers, and other participating organizations or interested individuals (usually by 4:00 p.m.).

There are now two basic types of Ozone Action Days:

  1. An Ozone Action Advisory will be declared when the AQI forecast is code orange, indicating that prolonged outdoor exertion is UNHEALTHY FOR SENSITIVE GROUPS (i.e., children and persons with asthma or other breathing problems). 
  2. An Ozone Action Alert will be declared when the AQI forecast is code red, indicating that prolonged outdoor exertion is UNHEALTHY FOR EVERYONE

In addition, UNUSUALLY SENSITIVE PEOPLE should routinely check the AQI as reported in newspapers and on the radio, television, and the Internet and consider limiting prolonged outdoor exertion when the AQI is code yellow.

A Web site dedicated to Ozone Action Days information has been set up by Metroplan.  ADEQ advises Metroplan on ozone-related issues and provides support.

The Technical Services Division of ADEQ calculates the local Air Quality Index (AQI), not to be confused with the Ozone Forecast.  It is a scale used to report actual levels of ozone and the other four major atmospheric pollutants of concern (http://www.adeq.state.ar.us/techsvs/airmain.htm).  The higher the AQI value the greater the health concern.