SAN FRANCISCO (CBS SF) — A number of Bay Area communities are seeing smoky conditions as a result of large fires in Northern California, and air quality conditions have reached unhealthy levels in some areas.

A view of the smoke settled over the Tri-Valley, August 31, 2017. (CBS)

San Mateo County and the Marin County Sheriff’s Office both reported heavy drift smoke from wildfires, enough for people to smell smoke. Residents were urged to keep windows closed if anyone has respiratory issues.

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The Napa County Office of Emergency Services also reported smoke from Northern California wildfires, but noted there were no fires in the county.

There were also no fires in the Lamorinda area, where the Moraga Police Department and Moraga-Orinda Fire Department each received calls about smoke.

Livermore-Pleasanton Fire Department Deputy Chief Joe Testa posted on neighborhood social network Nextdoor that the department had received numerous reports of smoke in the area, and also attributed it to fires burning in the state. Testa said there were no active fires in the region.

The Livermore Valley Joint Unified School District enacted inclement weather procedures at all school sites for Thursday and Friday because of the smoke and excessive heat. The district is limiting outdoor exposure of students and staff and canceling all athletic practices and competitions.

The Pleasanton Rage soccer club was among other local groups that have canceled all outdoor activities through end of Saturday.

The Bay Area Air Quality Management District (BAAQMD) said fires in Nevada and Butte counties were generating smoke that’s moving into the Bay Area. Also, smoke from Northern California and Oregon fires was coming down the coast and entering the area through the Golden Gate, the district said.

“We expect the smoke to last through Saturday and potentially through the weekend,” air district spokeswoman Kristine Roselius said.

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BAAQMD has issued a Spare the Air alert for the Bay Area for Thursday and Friday, marking 11 days this year that regional air quality officials have issued the alert warning of excessive smog.

Ralph Borrmann from BAAQMD says people need to take the spare the air alerts seriously because the particles in the air are from wildfires and are dangerous to breathe in. So while we see spare the air days often, this one is unique.

“When we get down to this level where we are saying its unhealthy, that is sort of a rarity,” said Borrmann.

Triple-digit temperatures, light winds, combined with smoke from wildfires elsewhere in Northern California and in Oregon, have created unhealthy levels of ozone in the region, according to BAAQMD.

“The Labor Day heat wave is expected to bring unhealthy air quality throughout much of the inland areas of the Bay Area,” air district executive officer Jack Broadbent said in a statement.

Air district officials were encouraging people to avoid exercising or doing outdoor activities during the hottest part of the day. People should also take public transit, carpool or consider working from home to avoid the number of cars on the road creating smog.

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