Skip Navigation
logo of MCDOT


   Montgomery County Department of Transportation
   Division of Transit Services  


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




For any MCDOT service request or complaint, call 311
When dialing outside of the county, call 240-777-0311 or submit via their website.

For website comments or to report website problems or broken links, please email us.
This email address does not handle service requests or complaints.

Transit Services · Montgomery County Department of Transportation
Questions/Comments · Inside Montgomery County dial 311 · TTY: 301-251-4850
Outside Montgomery County dial 240-777-0311