Much of the city was up late last night, as residents’ lizard brains prevented them from sleeping, sending alerts through grey matter that the house was on fire. This morning, photos flooded social media of bathroom sinks, back porches, and even dogs coated with ash. While we acknowledge that the inconvenience of bad air quality and having to dust tiny charred pieces of people’s burned homes off our Muni bus seats is a privileged position in today’s tragic events, many San Francisco residents — particularly those with respiratory issues — are suffering, too.

“Wildfire smoke is a mixture of gases and fine particles from burning trees and other plant materials,” writes the Centers for Disease Control and Prevention in a guide on the matter. “This smoke can hurt your eyes, irritate your respiratory system, and worsen chronic heart and lung diseases.”

Even those without pre-existing conditions can suffer side effects from smoke, such as headaches, trouble breathing, and a sore throat.

AirNow, an air quality site managed by the Environmental Protection Agency, lists current conditions in San Francisco as “unhealthy.” Based on their map, it appears that areas on the east and west edges of the city (near the water) are slightly less toxic than the central neighborhoods.

The Bay Area Air Quality Managment District issued a smoke advisory Monday morning, advising residents to limit outdoor activities. For those who are driving today, it’s recommended that air conditioning and car venting systems are set to re-circulate, to prevent outside air from entering.

While some city residents have turned to face masks to limit their exposure to particles, the CDC states that traditional masks, like those found in hardware stores, are only designed to capture large particles of matter such as sawdust. Tiny particles, such as those found in wildfire smoke, will still pass through the filters. Instead, the best masks to use to protect oneself are particulate respirators, commonly sold with the words “NIOSH,” “N95” or “P100” on the package. Masks should be replaced daily.

And as many local firefighters bravely tackle the flames in Napa, Sonoma and Santa Rosa, we can all do our part to keep San Francisco fire-free. Be extra cautious while cooking, burning candles, or smoking cigarettes indoors. Let’s hope that this blows over quickly, so our northern neighbors can begin the arduous process of rebuilding.

UPDATE, 12:30 p.m. The Department of Public Health announced that the city’s Homeless Outreach Team is performing wellness checks on city residents living on the streets. Those who request it are being transported to MSC South at 525 Fifth St., the Medical Respite and Sobering Center at 1171 Mission St., and Next Door Shelter at 1001 Polk St.

UPDATE, Thursday, Oct. 12. The Bay Area Air Quality Management District extended its health advisory and Spare the Air alert through the weekend. The fires are “causing unprecedented levels of air pollution” in the region, they say, and it will continue to be unpredictable.

As of Thursday morning, air quality in San Francisco, the Peninsula, East Bay, and Marin County is deemed “unhealthy.” If you see or smell smoke in your area, it’s recommended to stay indoors with windows and doors closed and to put any air condition units on recirculate.