There is no Spare the Air alert for Tuesday, Oct. 27. The Bay Area Air District's five-day forecast, last updated Monday morning, shows good air in most of the region.

AQI forecast by zone, Mon./Tue.

  • Northern Zone: 36 / 36 (Good)
  • Coast and Central Bay: 55 / 55 (Moderate)
  • Eastern Zone: 38 / 40 (Good)
  • South Central Bay: 37 / 38 (Good)
  • Santa Clara Valley: 50 / 44 (Good)

The forecast rates Wednesday through Friday as good in every zone except Coast and Central Bay, which stays moderate.

What the numbers mean

The AQI runs from 0 to 500. A reading of 0 to 50 is good, and 51 to 100 is moderate. In the moderate range, the district says unusually sensitive people should consider limiting prolonged outdoor exertion. The Air District says ozone is the main alert trigger from April to October and fine particles are the main trigger from November to February.

Wood-burning season starts soon

Burning wood is illegal on any Spare the Air alert day called for particle pollution. The district says wood smoke is the Bay Area's largest wintertime source of air pollution, at more than a third of fine particle pollution.

Related: our earlier smoke advisory coverage.