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Thursday, November 26, 2015
News Release

Contact: Stacey Welling 
Phone: (702) 455-3201 
Email: stac@ClarkCountyNV.gov 
Monday, April 01, 2013 
Ozone Season Arrives in Las Vegas Valley through September 

    The first day of April marks the official start of ozone season in the Las Vegas Valley.   Clark County’s Department of Air Quality (DAQ) has issued a seasonal advisory for ozone that covers the spring and summer months when weather conditions and levels of pollutants can trigger a build-up of ground-level ozone during afternoon hours. The advisory is in effect now through September.  

    “We’ve made a lot of progress in cleaning up our local air quality in recent years, but ozone pollution continues to be a challenge for our community and others in the Western states,” said Clark County Commission Chair Steve Sisolak. “We all need to do our part to help reduce ozone pollution this time of year.”              

    Ground-level ozone, a key ingredient of urban smog, can become a pollutant of concern in the Las Vegas Valley as early as April and continue through the hot summer months. Ozone pollution typically builds up during daytime hours. Contributing factors include strong sunlight, hot temperatures, and pollutants from automobiles and other sources such as wildfires, as well as air blown into the valley from either Southern California or the Gulf of Mexico at times when the Gulf also affects local humidity.              

    Unhealthy doses of ground-level ozone can reduce lung function and worsen respiratory illnesses like asthma or bronchitis. Exposure to ozone also can induce coughing, wheezing and shortness of breath even in healthy people. When ozone levels are elevated, officials advise everyone to limit strenuous outdoor activity. At this time, unhealthy levels of air pollution are not occurring. Air Quality officials monitor conditions and will post an alert on the forecast page of the DAQ website if unhealthy levels occur.              

    Air Quality officials encourage residents to sign up for free text and e-mail advisories and air quality forecasts through the U.S. Environmental Protection Agency’s EnviroFlash service at www.enviroflash.org. Daily air quality reports and forecasts also are posted on the department’s website. Five-day forecasts cover ozone as well as carbon monoxide and dust. Air quality officials also send advisories to local media, schools, government jurisdictions and the National Weather Service if weather conditions and other factors seem likely to trigger the formation of a pollutant of concern in the valley. Alerts are posted on the forecast page if any of the department’s 11 monitoring stations detect unhealthy levels of the pollutant at a single site in the valley over a specific period of time set by the EPA.       

    The public also is encouraged to take the following actions to help reduce the formation of ground-level ozone:  

  • Fill up your gas tank after sunset.
  • Plan errands so they can be done in one trip.
  • Try not to spill gasoline when filling up, and don’t top off your gas tank.
  • Keep your car well maintained.
  • Use mass transit or carpool.
  • Don’t idle your car engine unnecessarily.
  • Walk or ride your bike whenever practical and safe.
  • Drive an electric or hybrid vehicle, or low-emission scooter or motorcycle.
  • Turn off lights and electronics when not in use. Less fuel burned at power plants means cleaner air.       
  • Consider low-maintenance landscaping that uses less water and doesn’t require the use of gas- powered lawn tools to maintain.                            

    In December the EPA approved Clark County’s plans for maintaining the agency’s 1997 national ambient air quality standards for ozone. However, the EPA adopted more stringent standards in 2008. The 1997 standard was 84 parts per billion (ppb) over eight hours. The 2008 standard is 75 ppb. Two of the eleven monitoring stations in Clark County are one part per billion over the 75 ppb standard.  A part per billion is about equal to a single drop of water in an Olympic-size swimming pool.  

    “We have not yet been designated non-attainment of the 2008 health-based standard for ozone by the EPA, said Lewis Wallenmeyer, Director of the County’s Department of Air Quality. “We need to remain vigilant in our efforts to reduce ozone pollution or our community could face federal sanctions and the need to implement new measures to reduce emissions that will undoubtedly increase costs to the community.”              

    Local air quality has improved significantly since July 2001 when the County Commission was designated as the air pollution control agency for Southern Nevada.  In 1985 the valley logged a record 41 unhealthy air days due to carbon monoxide. In January 1993 the area was designated as serious non-attainment for particulate matter (PM-10), a form of dust pollution. The County now meets health standards for carbon monoxide and PM-10.        


    Clark County is a dynamic and innovative organization dedicated to providing top-quality service with integrity, respect and accountability.  With jurisdiction over the world-famous Las Vegas Strip and covering an area the size of New Jersey, Clark is the nation’s 12th-largest county and provides extensive regional services to more than 2 million citizens and 42 million visitors a year. Included are the nation’s 7th-busiest airport, air quality compliance, social services and the state’s largest public hospital, University Medical Center. The county also provides municipal services that are traditionally provided by cities to almost 900,000 residents in the unincorporated area. Those include fire protection, roads and other public works, parks and recreation, and planning and development.