SAN FRANCISCO (CBS SF) — Moderate air quality is expected to persist over the Bay Area this week as pollution from wood smoke stays near ground level, a spokeswoman for the Bay Area Air Quality Management District said Monday.

Cold temperatures overnight and the holiday season means more of the approximately 1.4 million fireplaces and wood stoves in the region are in use, air district spokeswoman Erin DeMerritt said.

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Between November and February, wood smoke is the largest source of pollution in the Bay Area.

Latest Bay Area Air Quality Data

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A weather pattern of warm air over cold air in the atmosphere is expected to act like a lid and keep wood smoke close to the ground.

A similar stagnant weather pattern was in place last week. Wood smoke and vehicle emissions contributed to less than ideal air quality then.

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