These reports contain pollution data measured across the state during the current day or previous day. They present the data in "RAW" form, meaning that the data you see are exactly what was collected electronically from each pollution monitor every hour. Please see the note and disclaimer below. 

NOTE: The links to these reports have changed as of 5/24/18. Please update any established bookmarks or hyperlinks to ensure you are seeing the correct data.

Please select from the following reports.

  • Previous Day's Highest Hourly Averages Report - This report is a listing of the highest hourly average reading recorded during the previous day for each of these parameters: carbon monoxide (CO), sulfur dioxide (SO2), ozone (O3), particulate PM10, particulate PM2.5 and nitrogen dioxide (NO2), as measured at monitoring sites operated by the Ohio EPA and Local Air Agencies in Ohio.
  • Today's Air Quality Readings - This report is a listing of the hourly air quality readings recorded during the current day, as measured at air monitoring sites operated by the Ohio EPA and Local Air Agencies in Ohio. The daily average and maximum readings are also listed, along with the hour of the maximum reading.
  • Yesterday's Air Quality Readings - This report is a listing of the hourly air quality readings recorded during the previous day, as measured at air monitoring sites operated by the Ohio EPA and Local Air Agencies in Ohio. The daily average and maximum readings are also listed, along with the hour of the maximum reading.
  • Yesterday's 8-hour and 1-hour Ozone Maximum Values by Site - This report is a listing of the highest 8-hour average Ozone value and highest 1-hour Ozone value, for every Ohio EPA and Local Air Agency ozone monitoring station for the previous day. Because the Ozone 8-hour average is a forward-rolling-average, the value for the 11:00 PM hour for a given day is calculated using data from 11:00 PM through 6:59 AM the following day. As a result, this report will show the full, previous, calendar day by 8:30 AM on a given day. Prior to that, from 12:00 AM until 8:30 AM each day, this report will still reflect two calendar days ago. All times EST. EDT will be an hour shifted from the times reported here.

Each of the options above will access reports of pollution data measured across the state during the previous day. These reports present the 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 nearly immediate data availability on this website. Thus, data seen here may not necessarily be "FINAL" data. Please bear in mind that what you see in these reports will not always be 100 percent accurate.

Some readings will include letters or numbers in place of or after the data value, called "FLAGS." These flags indicate that something other than normal sampling occurred during that hour, such as monitor maintenance or calibration, daily diagnostic tests, performance audits, monitor malfunction, etc. Hourly readings that are blank indicate that there was no data available for that hour, usually due to monitor malfunction or a problem in communication between the monitoring site and the central computer system that retrieves the data.

The reports available in this section present data from several types of air pollution monitors. These monitors continuously sample the air to detect levels of air pollutants harmful to public health and welfare. The data collected by the monitors is then used to assess each area's compliance with the National Ambient Air Quality Standards (NAAQS), which are maximum acceptable levels of each pollutant as designated by the U.S. EPA. The pollutant names, or "Parameter," along with the unit of measurement, or "Unit," for each, are:

Parameter Unit
Carbon Monoxide (CO) PPM (parts per million)
Sulfur Dioxide (SO2) PPB (parts per billion)
Ozone (O3) PPB (parts per billion)
Nitrogen Dioxide (NO2) PPB (parts per billion)
Particulate Matter (PM10) UG/M3 (micrograms/cubic meter)
Particulate Matter (PM2.5) UG/M3 (micrograms/cubic meter)
   

 

Groups sensitive to the effects of air pollution:

  • Particle pollution - People with heart or lung disease (such as asthma), older adults and children
  • Ground-level ozone - People with lung disease (such as asthma), and children and adults who are active outdoors