Los Angeles, California
"A residential no-burn alert will be in effect Wednesday in the South Coast Air Basin — which includes the greater Los Angeles area, Orange County and the Inland Empire — due to a forecast of fine particle air pollution.
Under the alert issued by the South Coast Air Quality Management District, residents are barred from burning wood in fireplaces until midnight."
Under California law, Title 17 Section 80110, the ARB (Air Resources Board) shall specify each day of the year as a permissive burn day, or a no-burn day for each air basin or other specified area.
UPDATE
They issued a no-burn day for 5 straight days! In the middle of winter! Are they serious? Why don't they just BAN wood-burning fireplaces permanently and be done with it. And also ban everything else that contributes to air pollution. Like smoking. And driving. And breathing.