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All you need to know about air quality

Air Quality Forecast

Air Quality Hot Line: Washington D.C. Metropolitan Area 202-962-3299


Air Quality Weather Conditions Recommended Actions


  • Hot (Mid 90's to 100's), hazy and humid
  • Stagnant air, little or no wind
  • Little chance of rain
  • Stationary high pressure system with sunny skies

When air quality reaches unhealthful levels:

  • Children and elderly individuals should reduce outdoor activities
  • Healthy individuals should limit strenuous outdoor work or exercise

When  air quality is forecast to reach unhealthful levels, residents are strongly urged to:

  • Limit driving and, when possible, combined errands
  • Use area bus and rail lines, or share a ride to work
  • Avoid mowing lawn with gasoline-powered mowers
  • Refuel cars after dusk

Unhealthfy for Sensitive Groups

  • Temperature is in the upper 80's to low 90's
  • Light winds
  • Slow-moving high pressure system with sunny skies
When air quality approaches unhealthful levels, residents are urged to:
  • Refuel cars after dusk to limit daytime pollution
  • Avoid mowing lawns with gasoline-powered mowers
  • Share a ride or drive only their newest, best maintained vehicle.


  • Mid summer temperatures (upper 70's to mid 80's)
  • Light to moderate winds (15 knots or less)
  • High pressure system with partly or sunny skies
When air quality is in moderate range, residents should:
  • Consolidate trips and errands
  • Limit idling when possible
  • Conserve electricity and set air conditioners to 78° F


  • Cool summer temperatures (mid 70's to low 80's)
  • Windy conditions (15-20 knots or higher)
  • Heavy or steady rain
  • Passing cold front carries pollution out of area
Throughout the ozone smog season (May through September), residents should make an extra effort to:
  • Carpool, use transit, bike or walk when possible
  • Keep cars and boats tunned-up
  • Use environmentally paints and cleaning products


Transit Services · Montgomery County Department of Transportation · 240-777-5800 · Fax: 240-777-5801 · 101 Monroe St · 5th Floor · Rockville, Maryland 20850 ·
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