Barred from gyms, schools and sporting events by COVID-19 restrictions, then forced indoors by wildfires, Bay Area residents are coping with yet another health threat: smoke leaking into their homes.

Sealing windows and doors, cleaning the air with air purifiers or filters, creating indoor space closed to the outside and drinking lots of water are some of the strategies suggested by authorities including the Centers for Disease Control and Prevention.

These precautions are all the more important with wildfire smoke causing elevated levels of particulate pollution that could leak indoors. The Bay Area Air Quality Management District on Saturday extended a Spare the Air alert through Aug. 26.

The first step to keeping polluted air out is to block it from seeping in through windows and doors, according to the air district. The district recommends caulking windows and using weather-stripping under doors. Instructions can be found on sites such as YouTube.

Tale of the tape

It is also possible to simply use paper towels held in place with painter’s tape. The latter material can be removed later without tearing off the paint.

People who have central air conditioning can use high-efficiency filters to capture fine particles from smoke, according to the Centers for Disease Control and Prevention. If the system has a fresh air intake, it should be set to re-circulate mode or the outdoor intake damper should be closed.

Portable air cleaners are good options, but not just any air purifier will do. For best results, the air cleaner should have a filter rated as “high efficiency” (high MERV) or HEPA, according to the U.S. Environmental Protection Agency.

Air cleaners under $200 “often do not clean the air as well and may not be as effective against wildfire smoke,” according to the EPA. Air purifiers should be non-ozone-generating.

Clearing the air

Another option is to create a “clean room,” sealing off all windows and outside doors and cleaning the air in the room with a portable air purifier.

“Stay hydrated by drinking water during heavy smoke events,” Sonoma County officials urged, cautioning that smoke can irritate the eyes and airways, causing cough, a dry scratchy throat and trouble breathing.

Adults “may benefit from wearing an N95 mask if they have one and must be outdoors. This helps protect you from unhealthy air,” according to Kaiser Permanente. Such masks can block the fine particulate matter in smoke.

Perhaps a bit of a silver lining: “Vacuuming stirs up particles already inside your home, contributing to indoor pollution,” according to the CDC. So, if nothing else, folks have at least a partial excuse from housework.