After dramatic improvement over the weekend, air quality deteriorated in some parts of the Bay Area on Monday as smoke again drifted in from the Glass Fire burning in the North Bay.

“We’ve still got the onshore winds that are kind of keeping the coast a little cleaner,” said Bay Area Air Quality Management District spokesman Juan Romero. “The northerly winds are bringing smoke into the Bay Area.”


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“Wildfire smoke is unpredictable,” he said.

On Sunday, air quality improved dramatically throughout most of the Bay Area as the winds pushed smoke from the Glass Fire in Sonoma and Napa counties toward the Central Valley.

On Monday afternoon, the only areas with good air quality were along the coast. In the central Bay Area, conditions were moderate, and farther east, they turned unhealthier. The North Bay also had a mix of moderate and unhealthy air.

A Spare the Air alert is in effect through Tuesday for the Bay Area. That means it is illegal to burn wood on those days.

“When the fires are burning anywhere in the air district and with the changing conditions, we want to make sure to keep the Spare the Air alert up,” Romero said.

According to Rick Canepa, meteorologist for the National Weather Service, the winds Monday were westerly, and should be more westerly and southwesterly, to perhaps even southerly through Wednesday.

“That looks favorable to keeping smoke from the Glass Fire away from the Bay Area through midweek,” he said.

Canepa said the Bay Area forecast for the next couple of days calls for temperatures in the 70s closest to the coast, in the upper 70s to mid-80s in the central Bay Area, and in the upper 80s to 90s in the outer portions of the East Bay and beyond.

Romero said rapidly changing conditions during this wildfire season have made predicting air quality particularly difficult. He suggested people regularly check the air quality before deciding to spend time outdoors.

“When conditions are forecasted to be unhealthy, people should stay indoors with the windows and doors closed if temperatures allow, which is the best way to protect themselves from the smoke,” he said. “If they can’t keep cool at home, go to a cooling center with filtered air.”

Air quality resources:

• The Bay Area Air Quality Management District collects and posts searchable AQI readings from air monitors around the region. You can also sign up for air quality alerts and get information about health and safety.

•, a partnership run by the EPA including federal, state and local air monitoring agencies, offers a “one-stop source for air quality data,” including interactive maps with local, national and world views. It also offers a Fire and Smoke Map with current fire conditions and air quality data including readings from the crowdsourced PurpleAir network.

• The Chronicle’s California Air Quality Map lets you zoom in to see readings in your area. It draws from the PurpleAir network and is updated every 10 minutes.

• This Chronicle guide explains different ways to look up the air quality in your microclimate.

• This explainer helps you assess when it’s OK to go outside if it’s smoky in the Bay Area, and what level of activities you can safely engage in.

• This explainer details the do’s and don’t of dealing with smoky air in your Bay Area home and car.

Kellie Hwang is a San Francisco Chronicle staff writer. Email: [email protected] Twitter: @KellieHwang

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