A record number of alerts banning wood fires were issued this winter during the Spare the Air season that ended Feb. 29, according to the Bay Area Air Quality Management District.
The district, which issues alerts when air pollution levels are expected to exceed safe limits, issued 15 alerts this winter.
Officials reported 10 days when pollution levels exceeded the national air quality and another nine days that came close. The high level of alerts, the highest in five years, was due to a winter of unusually dry, stagnant weather, district officials said.
"It was a tough winter for air quality and public health, but things could have been much worse," said Jack Broadbent, the district's executive officer. "Wood burning overall is decreasing, but we still see unhealthy levels in certain neighborhoods throughout the Bay Area."
Wood smoke, the single largest source of winter air pollution in the Bay Area, contains particulates and carbon monoxide and is linked to respiratory illnesses such as asthma, bronchitis and lung disease.
Violators of the ban on wood burning receive a warning letter for the first offense and a $400 ticket for additional offenses. The district received 3,777 complaints about wood smoke from residents and issued 346 warning letters and 13 tickets.
The highest number of complaints were made in Santa Clara, Marin and Contra counties, but the highest number of warning letters were issued in Sonoma County residents, where 108 people were observed to be in violation of the ban.
Air pollution from wood smoke is down 15 percent over the past five years, according to the district.
--Bay City News and Michelle Fitzsimmons