When cities and counties in the Bay Area adopt the ordinance, it allows the installation of

• Natural gas fireplaces which are the cleanest air quality option. Natural gas fireplaces generate a fraction of a gram of PM per hour.
• EPA certified wood heaters which meet EPA's particulate emission standard of 7.5 grams per hour. They incorporate combustion controls -- generally a secondary combustion zone, or use catalysts akin to the catalytic converters used in motor vehicles.
• Pellet-fueled wood heaters which burn cleaner because they control the mixing of fuel and air more tightly than conventional woodstoves. Emissions of virtually all pellet stoves are substantially lower than EPA standards.
• Fireplaces certified by EPA to have emissions no greater than those of an EPA certified wood heater. At present, EPA does not have such a certification program. However, the Northern Sonoma Air Pollution Control District has developed a protocol for testing fireplaces. As of September 2003, no fireplace manufacturers have submitted data to the Air Pollution Control District that indicates they can meet the 7.5-gram per hour PM standard.

The model ordinance also contains the following prohibitions:

1. A prohibition on wood burning when the Air District issues a "Spare the Air Tonight" advisory. Spare the Air Tonight asks residents not to burn wood because of unhealthy levels of PM.
2. A prohibition against using certain fuels, such as garbage and plastics, in a wood burning appliance.

When a city or county adopts the model wood smoke ordinance, enforcement takes place through the permit process at local building departments. The ordinance requires residents to provide documentation that the device to be installed is allowed by the ordinance.

Since the ordinance was promulgated, Air District staff have worked with health agencies and interested residents in the Bay Area to advocate for the adoption of the ordinance. As of April 2006, the ordinance had been adopted by 41cities and eight of the nine Bay Area counties.

Air Quality Benefits of the Model Ordinance
Air District staff calculate that for every 1,000 new homes built in accordance with the provisions of the ordinance, three tons of PM10 are avoided each winter based on the assumption that:

• the average residence burns 0.28 cords of wood per winter season;
• 90 percent of the homes have wood burning fireplaces; and
• 38 percent of homeowners burn wood during the winter season.

There is also a corresponding decrease in carbon monoxide and toxic air contaminants generated by the burning of wood.

The wood smoke ordinance gives local communities better control over the quality of their lives, contributes to cleaner air, and reduces health costs. It also assists local air districts in attaining and maintaining federal and state PM standards in a reasonable, cost-effective manner.