A Public Health Challenge  

Ground ozone is problem pollutant in the Valley on hot summer days.  The pollutant is formed from NOx and Volatile Organic Compounds (VOCs) in the presence of sunlight.  Vehicle emissions and emissions from industries, power plants and products such as solvents and paints are among are sources we can control that contribute to ground ozone levels that can cause or aggravate health problems.  The federal standard for ozone was strengthened in 2015 and the Environmental Protection Agency has designated an area that include the City of Tempe as being in marginal non-attainment with the new ozone standard.   

Avoid idling your car, make use of public transportation, do not fuel gasoline during the hottest hours of the day are examples of measures that help reduce ozone levels.