That’s Not Just Fog Today. The Air Quality Is Terrible.

After last night's pleasant sunset, today's Air Quality Index is "Unhealthy."

There’s a reason you’re sneezin’ today. (Cal Fire)

This post has been updated with a quote from an esteemed meteorologist.

Is everybody in your office sneezing? Everybody in our office is sneezing. Although you could see genuine sunlight late into the afternoon yesterday, this summer has been so foggy that we’ve just gotten used to near-perpetual overcast days.

But today, the marine layer is mixed with genuine smoke from the fire complex up north and a relatively high humidity level to create hazardous conditions for anyone who inhales. It’s not a Spare the Air Day, but as of noon, the Air Quality Index (AQI) for San Francisco is 153, which is in the “Unhealthy” category — although just barely. That means “everyone may begin to experience health effects,” and “members of more sensitive groups may experience more serious health effects.” In other words, it’s not fog — it’s toxic haze.

(airnow.gov)

Curiously, the especially poor air seems localized to San Francisco and the northern reaches of the Peninsula, while the rest of the core Bay Area falls in a lower category and regions much closer to the fires are merely “moderate.” The marine layer is trapping a high amount of particulate matter, and that’s why our noses are tickling. Via tweet, meteorologist Daniel Alrick (@SFmeteorologist) tells SF Weekly that “Smoke from fires farther north (Pac NW & Canada) moved out over the Pacific in recent days, and onshore winds are now bringing that smoke into the central Bay Area.”

Cancel that Aqua Zumba kettlebell toss at Ocean Beach and stay the hell inside today.

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