Michael A crackling fire in the fireplace spreads cozy warmth and a comfortable atmosphere. However, instead of logs, we tend to burn 4-hour Duraflame logs from the supermarket (Rundbrief 11/2004) because burning wood not only involves work in obtaining it, but also requires constant replenishing.
This type of heat generation is not entirely environmentally friendly, and therefore the city of San Francisco prohibits the burning of material in fireplaces on particularly hot or smoggy days. This applies not only to the handful of days designated as official Spare-the-Air Days (Rundbrief 07/2006) which are declared and the city makes public transportation is partially free to entice commuters to leave their cars at home.
Whether or not fireplaces are allowed on a particular day can easily be checked on the Air Quality Forecast site on the internet. If there is a green sign, you are allowed to light a fire in the fireplace, but if it is red, it is prohibited under penalty. It is rumored that mobile teams patrol the city on prohibited days, observing chimneys for suspicious smoke plumes. Law-abiding citizen can register on baaqmd.gov and then receive emails with the current conditions. Addendum 01/2014: The rag H alf Moon Bay Patch reports that offenders who burn wood in the fireplace during Spare-The-Air days must pay a $100 fine.
However, the ban only applies on certain days during the "Spare the Air Season" from early November to the end of March. In April, we were allowed to fire up as much as we wanted again and make the apartment comfortably warm while the outside temperature was a chilly 13 degrees Celsius.