During No-Burn days, residents are prohibited from burning wood in their fireplaces or any indoor or outdoor wood-burning device. The No-Burn rule prohibits burning wood as well as manufactured fire logs, such as those made from wax or paper.

Alternatives to wood burning include clean-burning gas or alcohol fuel log sets, installed directly into an existing fireplace. These items can give the same warmth and feel of a traditional fireplace, but emit less pollution.

No-Burn Alerts are issued when emissions and stagnant weather cause unhealthy levels of fine particulate pollution. Since 2011, mandatory wood-burning curtailments from November through February have been in effect during days when poor air quality is forecast. 

The South Coast Air Basin currently has some of the highest levels of fine particulate pollution in the United States, according to the South Coast AQMD.

The region's estimated 1.2 million wood-burning devices are significant sources of air pollution, emitting an average of 5 tons of particulate matter per day. During the winter, when wood burning is at its peak, wood burning is estimated to cause more than 10 tons per day of particulate matter emissions - equal to nearly seven times the amount of daily primary particulate matter emitted from all of the power plants in the Southland.

Additionally, wood burning in fireplaces can pollute indoor air with fine particulates and toxic air pollutants.