OAKLAND, Calif. — My neighbors are picking lemons from their tree in gas masks. My husband is overnighting us particulate masks to breathe through because Home Depot and all the Ace Hardware stores nearby are sold out, just like they sold out of every single fan in August, during the heat wave. It’s the latest version of California’s new normal: Add masks to your emergency kit, don’t breathe deeply and try to stay inside.

When I woke up one morning last week with a nose bleed and a wracking cough, I decided to give in and order that particulate mask, but first I consulted with friends. “Is N95 the same as P95?” Liat asked, as we huddled over my laptop. My nurse friend said to search for N95, but the old bepreparedcalifornia.ca.gov pdf that is circulating uses a “P,” and Keally says the one put out by the pre-Pruitt Environmental Protection Agency is better. Seth sends out more links about smaller-size masks to a group of neighborhood parents because the ones we bought don’t come in kid sizes.

It’s been seven days now of some of the Bay Area’s worst ever air quality, and most of the fires north of us in Sonoma, Napa and Mendocino counties are minimally contained, or not at all. The smog enveloping Oakland, Berkeley, San Jose and other cities is literal and figurative: There has been little clarity about how best to protect ourselves. The consensus seems to be that we’re not supposed to exercise, that we should refrain from driving as much as possible and that if we do venture outside we should be wearing the kind of heavy-duty face masks that keep out the smallest particulate matter, these gray ashes that are falling from the sky.

My friend Iris and I brainstorm about the most airtight public spaces, places like movie theaters or hospitals that can filter air for large numbers of people, so we can gather there. She researches which filters really work for smoke pollution, and texts a group of us to say her living room will have the filter on at all times for anyone who needs to come over.