Sonoma County air quality the worst it’s been in two years

Sonoma County, the Bay Area and a wider swath of California is in the midst of a historic stretch of poor air quality, smashing smog records and catapulting air quality readings into the rarely seen “very unhealthy” category.

The air hasn’t been this foul in the North Bay for two years, stretching back to California’s last record-breaking wildfire, air quality officials said.

Friday was the 25th consecutive day that Bay Area air quality regulators declared a Spare the Air day because of smoky, smoggy conditions.

A gray-white pall hung over Sonoma County most of the day, not as eerie or as oppressive as the orange glowing skies earlier in the week, but still blocking out much of the sun until midafternoon. Visibility was a little as a quarter-mile for much of the day.

Early indications Friday looked like the sun might peak through this weekend, with partly sunny skies in the weather forecast.

But by midday, particulates in the air from the multiple massive fires burning throughout the state and West Coast still hadn’t shown improvement.

In fact, the air was getting murkier, said Kristine Roselius of the Bay Area Air Quality Management District.

That data led to the district to extend the Spare the Air alert through Monday, when it will mark the 28th straight day of alarmingly poor air quality in the Bay Area, a record run after its 14th day. The previous record was set during the 2018 Camp fire, the state’s deadliest and most destructive inferno.

“That is not only a record, it’s actually double the record,” she said of the previous mark, set during the Camp fire, the state’s deadliest and most destructive inferno.

Health officials warned residents to stay inside on days like Friday, when tiny particles in smoke and other pollutants irritate the eyes, nose and respiratory system. Long-term exposure to those tiny bits can aggravate heart and lung disease.

The air quality Friday morning had crept up into purple on the EPA’s color-coded ladder of ratings. Purple signifies a particulate pollution rating of between 201 and 300 and is categorized as very unhealthy.

The next lowest level is orange for “unhealthy for sensitive groups” like those with lung or heart issues. Sonoma County has floated within that level and the one below it, “moderate,” for three weeks, since Aug. 19.

That was two days after the lightning-started blazes began in Sonoma, Napa, Mendocino and other counties, where the rampaging fires would soon shatter all-time marks for acreage burned.

Only three days since mid-August has Santa Rosa showed clearing and retreated into the “good” air quality zone, according to data from IQAir, which touts itself as the world's largest free real-time air quality information platform.

The hot, dry and windy extreme-fire weather ― along with all the burning trees and other vegetation ― have given rise to six of the largest 20 fires in California history. That grim list is topped by the fires that have merged in the Mendocino National Forest, called the August Complex, which has blackened almost a half-million acres.

Those fires, particularly in Sonoma and Napa counties, have ceased to be an immediate threat to homes or lives, but they are still burning and producing ash and smoke.

Roselius of the air quality board said meteorologists initially hoped winds might blow away some of the smoke this weekend.

She said the marine layer that was essentially holding smoke above it Thursday night developed holes, allowing the heavier smoke to drop through.

“Unfortunatel,y it pretty much collapsed and we have smoke everywhere,” she said. “So now there’s an even thicker blanket of smoke above us, and new smoke being generated by the fires.

“Normally we have onshore winds and it clears us out, but now we just have smoke.”

The National Weather Service forecasts patchy fog and haze through at least Sunday afternoon and predicts sunny skies for Monday.

But air quality forecasts showing more smoke may dash hopes of a semiclear weekend.

Sonoma County’s air quality was was expected to remain in the “very unhealthy” category through Saturday.

Sunday and Monday are expected to move to the slightly less urgent “unhealthy” zone before possibly clearing to “moderate” on Tuesday.

Areas farther north, including Ukiah, are expected to have unhealthy to very unhealthy air Friday and into midday Saturday, according to the weather service.

You can reach Staff Writer Lori A. Carter at 707-521-5470 or lori.carter@pressdemocrat.com. On Twitter @loriacarter.