Calistoga Recovery

Cal Mart clerk Maria Espinoza wears a mask while serving customers at the grocery store on Monday as residents began returning to Calistoga following days of mandatory evacuations resulting from wildfires in the region.

The fires in Napa County are mostly contained, but that doesn’t mean residents can put their respirators away just yet. Smoke from wildfires across the Bay Area – including Napa, Sonoma and Solano counties – are continuing to contaminate the air, making it harmful to even breathe.

The Bay Area Air Quality Management District issued a health advisory in addition to a Spare the Air alert for Wednesday and Thursday, and says that the conditions may continue for “days to come,” according to a press release.

In the past two weeks, parts of the Bay Area have experienced air quality levels that are historically bad, said Walter Wallace, air district spokesman. Although levels were at times “hazardous,” he said, they’re comparable to a normal day in Beijing, China.

The Environmental Protection Agency measures air quality with Air Quality Index (AQI) numbers ranging between zero and 500. Air quality conditions are “good” when the AQI is between zero and 50, “moderate” between 51 and 100, “unhealthy for sensitive groups” between 101 and 150, “unhealthy” between 151 and 200, “very unhealthy” between 201 and 300, and “hazardous” between 301 and 500.

Air conditions in Napa were “unhealthy” Wednesday morning when the AQI hit an estimated 179 at 8 a.m. and 163 at 10 a.m. – the worst conditions in the Bay Area, according to the air district website. Conditions looked at little better in the afternoon when the AQI decreased to 115, “unhealthy for sensitive groups.”

Air quality, which had reached “hazardous” levels last week, had improved over the weekend, but took a turn for the worst on Tuesday, when it reached an estimated AQI of 158.

Napa County’s highest AQI so far this month was Oct. 10 when it reached estimated 378 – a “hazardous” level.

“Although air quality is improving in much of the Bay Area, smoky conditions will persist near and downwind of active wildfires,” said Jack Broadbent, district chief executive officer. “While the wildfires are still burning, the public should monitor air quality conditions and avoid outdoor activities if they smell smoke.”

Smoke can irritate eyes and airways, and cause symptoms including coughing, a scratchy throat and irritated sinuses, according to the air district. Elevated particulate matter in the air can trigger wheezing in people with asthma, emphysema or chronic obstructive pulmonary disease, also known as COPD. Children, the elderly, and individuals with respiratory illnesses are particularly susceptible to elevated air pollution levels and should take extra precautions to avoid exposure.

Residents impacted by heavy smoke should seek buildings with filtered air, like a public library or shopping mall, or move outside of the impacted area until smoke levels subside, says the district.

The closest cities for Napa County residents to visit in order to escape the “unhealthy” air conditions Wednesday were Vallejo, Concord, Oakland and Berkeley, where conditions were “moderate.” For “good” air, residents would have to travel into Sebastopol, just southwest of fires raging in Sonoma County.

Keep checking conditions, though, because “weather patterns and wind patterns can shift drastically” and blow smoke into other regions of the Bay Area, says Wallace. “The air quality can change dramatically within ... hours,” he said.

For those who can’t get away, the District recommends wearing N95 masks to help minimize breathing in fine particles. The district said Wednesday that it planned on delivering 40,000 N95 masks to fire-impacted counties, including Sonoma, Napa, Solano and Marin counties and evacuation shelters.

When properly fitted, N95 masks help filter fine particulates in wildfire smoke, but Wallace advises not to rely on them too much.

“We don’t want people to believe they’re completely protected when they’re not,” says Wallace. Something as simple as a beard or other facial hair can cause the mask to be improperly fitted, he said. Even if the mask helps filter out the particulates, you’re still being exposed. Ideally, when conditions are poor, stay inside, keep windows closed, recirculate the air conditioning and avoid any strenuous activity like working out.

Napa Valley Unified, St. Helena Unified, Calistoga Joint Unified, Howell Mountain Elementary and Pope Valley Union Elementary schools will not be open to staff or students when conditions are deemed “very unhealthy” or “hazardous.”

Continued poor air quality has delayed the planned reopenings of these districts until Monday. Napa Valley College is also closed until then.

There is hope for better air quality this week, albeit temporary, says forecaster Steve Anderson at the National Weather Service in Monterey.

Increased winds accompanied by some light rain should bring Napa County some relief Thursday and Friday, Anderson said.

Southwest winds were blowing smoke right into Napa County Wednesday, causing unhealthy air quality, Anderson said. As winds increase Thursday and Friday, though, the smoke is expected to blow north and out of the area, he said.

There’s a 70 percent chance of rain Thursday night through early Friday morning, he said, amounting to about a tenth of an inch.

“Any rain will, of course, be helpful,” he said. “That will help clear some of the air quality.”

Anderson called the two-day period a “brief relief” as hot, dry weather is expected to return over the weekend.

“We’ll be back to where we were when all this started, so we’re not out of the woods yet,” Anderson said. Temperatures should be around 80 degrees over the weekend and 85-90 degrees Monday through Wednesday. High winds aren’t expected, but humidity will be low early next week, he said.

Anderson said Wednesday afternoon that it’s too early to say whether or not more red flag warnings will be issued next week but it is possible.

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Maria Sestito is the former Napa Valley Register public safety reporter. She now writes for the Register as a freelancer.