Opacity Limits

State law prohibits the generation of excessive chimney smoke. Except for brief periods during start-up and refueling, smoke is in violation when it obscures objects viewed through it by more than 20%. Spokane Clean Air's air quality specialists are certified opacity readers and are recertified every six months.

Pictured above is what smoke looks like at densities of 20%, 40% & 80%.

After start-up, check out your chimney. If you see more than heat waves, provide more air (open your damper) to your fire.  Smokey chimneys may also be the result of burning "wet" or "unseasoned" wood.  To dry firewood properly, it should be split, stacked and loosely covered at least six months prior to burning. If it is not properly seasoned, it will result in less heat and more smoke. 

Generation of smoke densities greater than 20% can result in fines issued by Spokane Clean Air. Stoves, fireplaces and inserts operated with dry wood and a generous air supply produce less smoke and more heat. For more information on wood heating, including a link to a 4-minute video, "How to operate your wood stove more efficiently," click here.