Ground-Level Ozone Maps
(Available May through September)

In most areas, ozone concentrations are likely to be highest between the months of May and September. All citizens should be aware of the potential health risks that exposure to ozone can cause. Ozone maps will be made available to the public as a result of this project to help inform people about the daily levels of ozone pollution in their local areas. The color scheme on the maps will help people learn about the kinds of things they can do to protect their health as well as the health of the environment.  Please see our Note and Disclaimer below. Read the FAQ's below to learn more about ozone maps.

Please select from the following Ozone Maps:

  • Animation for Ohio

    This map is an animated representation of Ozone readings, calculated for an EIGHT-HOUR period, for all Ohio EPA and Local Air Agency monitoring sites for the previous day. Ozone levels are divided into five scales, with a different color assigned to each scale. The viewer can then equate the map colors with the different levels of Ozone throughout the state. The time of day is noted at the bottom of the map, and as the time of day changes, the map colors change to depict the varying levels of Ozone throughout the day.

  • 1-Hour peak of Ozone in Ohio

    (Available May through September)
    This map is a representation of the highest ONE-HOUR Ozone readings for all Ohio EPA and Local Air Agency monitoring sites for the previous day. Ozone levels are divided into six scales, with a different color assigned to each scale. The viewer can then equate the map colors with the different levels of Ozone throughout the state.

  • AQI --  8-hour peak of Ozone in Ohio

    This map is a representation of the highest Ozone readings, calculated for an EIGHT-HOUR period, for all Ohio EPA and Local Air Agency monitoring sites for the previous day. Ozone levels are divided into five scales, with a different color assigned to each scale. The viewer can then equate the map colors with the different levels of Ozone throughout the state.

  • Midwest

NOTE: These maps represent ozone pollution data measured across the state during the previous day. These maps are created using data in "RAW" form, meaning that the data you see are exactly what was collected electronically from each pollution monitor several times during each day. It is important to remember that "RAW" data are never considered valid until verified by Ohio EPA and Local Air Agency personnel, a process that can take much more time than the near real-time data available on this web site. Thus, data seen here may not necessarily be "FINAL" data. Thus, please keep in mind that what you see in these reports will not always be 100% accurate and are subject to change!

Ozone (O3) Mapping Project

Frequently Asked Questions:

  1. What is Ozone?

  2. What are the effects associated with exposure to ozone?

  3. What is the Ozone Mapping Project?

  4. How is ozone mapping helpful to you?

  5. How are the maps created?

  6. What types of maps are available?

  7. Where can I see the Ozone Map?

  8. How can I get more information about the Ozone Map?

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What is Ozone?

  • Ozone is the primary ingredient of smog in our cities and other areas of the country. Though it occurs naturally in the stratosphere to provide a protective layer high above the earth, at ground-level it is the prime ingredient of smog.
  • Ground-level ozone is formed when volatile organic compounds and nitrogen oxides react in the presence of sunlight. Sources of volatile organic compounds and nitrogen oxides include automobiles, power plants, gas stations, paints, cleaners, aircraft, locomotives, and lawn and garden equipment.
  • Ozone concentrations can reach unhealthy levels when the weather is hot and sunny. Ozone does not form as readily when temperatures are cooler, and/or when steady rain occurs.

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What are the health effects associated with exposure to ozone?

  • While beneficial in the upper atmosphere, ozone in the lower atmosphere can cause a variety of health problems because it damages lung tissue, reduces lung function, and adversely sensitizes the lungs to other irritants.
  • Children, especially asthmatic children, are at special risk for adverse health effects from the dangers of ozone pollution. Children playing and exercising outside in the summertime, the season when concentrations of ground-level ozone are the greatest, may suffer from coughing, decreased lung function, and have trouble catching their breath. Asthmatic children and adults are much more likely to have asthma attacks. Medical studies have clearly shown that ozone can aggravate asthma, causing more attacks, increased use of medication, more medical treatment and more visits to hospital emergency rooms. Ten to twenty percent of all summertime respiratory-related hospital visits in the Northeastern US are associated with ozone pollution.

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What is the Ozone Mapping Project?

  • In 1996, President Clinton made a commitment to increase the availability of environmental information in Kalamazoo, Michigan that has become the "Right to Know Initiative". Under this initiative, EPA created the EMPACT (Environmental Monitoring for Public Access and Community Tracking) project. The ozone mapping project is the first activity of this project to be delivered to the public.
  • EPA worked closely with the States to develop and implement the ozone mapping project. The project uses real time data from over 400 monitoring stations located in 21 Eastern and Midwestern states to provide a picture of ozone levels throughout the day. Color-coded, animated images show how ozone forms during hot summer days and can be transported to areas downwind from sources of pollution. The maps generated allow local media to deliver accurate and timely health messages about ozone pollution.

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How is ozone mapping helpful to you?

  • In most areas, ozone concentrations are likely to be highest between the months of May and September. All citizens should be aware of the potential health risks that exposure to ozone can cause. The ozone maps that will be made available to the public as a result of this project will help inform people about the daily levels of ozone pollution in their local areas. The color scheme on the maps will help educate people about the kinds of things they can do to protect their health as well as the health of the environment.

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How are the maps created?

  • The monitors, which are operated by the State and local agencies, collect ozone concentrations over 5- to 20- second intervals, and report the data as averages over 1-hour intervals. From mid-May through mid-September, the State and local air pollution control agencies poll monitors between 2 and 7 times a day. Then, they send the 1-hour average concentrations to a central data collection center at EPA's Office of Air Quality Planning and Standards in Research Triangle Park, NC, where the maps are generated and posted to EPA's web site.
  • The color contours of ozone concentrations on the maps use a 5-color scale. Each color corresponds to a range of concentrations and indicates a level of air quality (good, moderate or unhealthy).

    Green color = Good

    = Moderate

    = Unhealthy for Sensitive Groups (i.e. children and asthmatics)

    = Generally Unhealthy

    = Very Unhealthy

     

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What types of maps are available?

  • In this project, EPA will generate 3 types of maps: still-frame maps of peak daily ozone concentrations, animated movies of ozone concentrations throughout each day, and still-frame forecast maps of the next day's predicted peak ozone concentrations.
  • Began in 1998, EPA generates animated movies and peak daily concentration maps for 17 mapping domains (different sub-sets of the entire 22-state region). EPA will update the animated movies throughout the day within an hour after each polling time (northeast and mid-Atlantic states will poll their ozone monitors from 8 a.m. through 10 p.m. EDT; the Midwestern states will poll their monitors at least at 7 a.m. and 7 p.m. EDT with an additional optional poll at 3 p.m. EDT). U.S.EPA will also produce forecast maps for the following day.
  • By providing the information about ozone levels in local areas, the ozone maps provide the public with an opportunity to take precautionary measures to limit exposure as well as actions to reduce pollution.

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Where can I see the Ozone Map?

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How can I get more information about the Ozone Map?

  • For more information about the ozone maps contact your state or local air pollution control agency or visit EPA's website at http://www.epa.gov/airnow.

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Note: Data in these reports are always referenced to Eastern Standard Time (EST).  Air Quality Index reports are updated several times during a day at 15 minutes past the hour ( 8A.M. - 10 P.M. EDT)

Disclaimer: The data in these reports have neither been validated nor quality assured by State or LAA Air Monitoring Agencies. These data may change and are not considered official until QA/QCed -- odd data are suspect invalid due to possible equipment trouble or telemetry problems.