Update, October 16: After a long weekend during which new fires started south of San Francisco while some northern fires inched toward containment, Monday’s Air Qualify Index (AQI) prediction spells relief for Bay Area residents suffering from the smoggy exhalations of the encircling infernos.
Air Now anticipates an average San Francisco air quality of 89 on Monday. That’s still about twice as bad as our usual air, but only qualifies as a “moderate” problem on the EPA’s six-classification scale, the sort of thing that should immediately affect “unusually sensitive people.”
Note that conditions ticked up to a more alarming 110, or “unhealthy,” just before 10 a.m.
Although predictions for last Friday appeared dire, the agency’s index indicates in hindsight that the actual average air quality that day in the city was about 98—not great, but not nearly as bad as expected.
Saturday saw the figure drop into the high 70s, and then Sunday even back down to a transcendent and downright normal 40 for the day.
The Environmental Protection Agency’s (EPA) site Air Now predicts that air quality on Friday will be even more smoky, smoggy, and hazardous to the public health than the previous haze all week, which turned the sun pink and replaced San Francisco’s usual foggy overcast with a Beijing-like funk.
The air quality forecast for today anticipates “unhealthy” conditions and gives the unsightly miasma an index score of 158.
For perspective, for the first week of October, before a series of fires stretching from Napa County to Butte County broke out, the Air Quality Index for San Francisco averaged 41.5—generally very good.
In famously smoggy Los Angeles, the predicated air quality Friday should average around 74—not great, but not a particularly pronounced hazard either, ranking as “moderate” on the EPA scale.
And according to the U.S. State Department, the hazard level in Beijing, China, which has one of the least healthy atmospheres of any major city worldwide, crept up to 161 once in the past 24 hours, but stayed beneath present San Francisco levels for almost the entire day.
When air quality gets worse than 150, the scale indicates that “everyone may begin to experience health effects” and that “members of sensitive groups may experience more serious health effects.”
The EPA advises that sensitive groups like children, the elderly, and those with existing respiratory problems should “avoid prolonged or heavy exertion” on days like this, while others should “reduce prolonged or heavy exertion.”
Business Insider reported earlier this week that San Francisco stores were already selling out of protective face masks.