[UPDATE: This provision was removed Jan. 27, 2010, see previous post: Over 30 Residents Testify, Wet Wood Retained on Prohibited Fuels List.]
The local Air Quality Ordinance, 2010-28, has a provision prohibiting smoke opacity greater than 50% (page 7) after 9/1/2011.
What does 50% opacity look like? See page 5 of this FNSB written notice of restrictions for solid fuel-burning devices to see what 25%, 50%, and 75% opacity look like. Also view this set of photos posted on Puget Sound Clean Air which shows opacity levels of 20%, 40%, and 80%.