October will long be remembered in Northern California, where wildfires destroyed over 8,000 structures, killed scores, and forever changed Sonoma and Napa counties. Survivors face new threats and hazards seldom addressed in design-build magazines and chat rooms.
We instinctually fear flames from wildfires, but smoke and dust impact more people than fires. The young, pregnant, elderly, and anyone with a respiratory illness, such as asthma, are especially at risk. Even the healthiest individual can succumb to illness or death if they inhale too much smoke or dust.
Smoke from burning buildings and cars contains dangerous chemicals and heavy metals not found in your average campfire. Here are some best practices for minimizing exposure during wildfire season.
Air Sealing & Ventilation
Home Energy Magazine readers are familiar with air sealing to minimize heat loss, but emergency air sealing involves temporary measures you may not have considered.
- Keep windows and doors closed.
- Shut off outside air intakes for forced air systems. This may include temporarily covering attic or crawlspace vents, incoming air ducts for HRVs/ERVs and central forced air systems. (Note: Contact your HVAC professional to make sure it’s okay to block these vents. Doing so—on some units—may increase static pressure and burn out a fan.)
- Some ventilation systems are designed to filter outside air. These systems may continue operating if they do not noticeably worsen indoor air quality. While standard media filtration may effectively remove fine particulates, it will most likely do nothing to reduce smoke odors and combustion gases.
- If possible, minimize use of exhaust fans such as those in bathrooms and over stoves, and don’t forget that a clothes dryer is a huge “vacuum” that can cause significant outside air infiltration.
- Run central ventilation fans in recirculation mode. This process—even with standard residential air filters—has been found to successfully remove fine particulates from the air. This is true when you’re in a vehicle, too.
Protecting Yourself from Dust and Smoke
So now that you’ve done the above, how do you protect yourself from smoke and dust indoors?
- When it’s really dusty or you’re doing dust-generating work like cleaning, playing, or moving furniture or boxes, you should consider wearing a mask to reduce fine particle A typical “dust mask” does very little good. A rated N95 maskis suitable and recommended for most DIY situations. If you have a beard you’ll need a full-face respirator, which are considerably more expensive and effective.
- Use a plug-in HEPA air purifier or scrubber 24/7, but especially during and after cleaning and while sleeping.
- Clean using best practices for minimizing aerosolization of fine particulates:
- Wet-wipe and discard used rags. Do not dry dust with a feather duster or rag.
- Mop instead of sweeping. Wet mopping will capture more fine particulates and collect them in the waste bucket. Sweeping creates massive amounts of airborne dust.
- Use a True-HEPA vacuum on carpets, floors, couches, beds, and so on. Vacuum only when you’re just about to leave the space for some time. Vacuuming, even with a HEPA vacuum, will generate significant dust in the air. Leaving right after you vacuum allows that fine particulate to settle out of the air while you aren’t around to breathe it in. Vacuuming a bedroom right before bed is not advised.
- If you can afford it, hire a professional for cleaning mold, getting rid of asbestos, and for lead abatement.
Immediate Threats After a Fire
These basic measures may save your life when you return to clean up after a fire.
- Do not reenter a fire stricken area or building unless a professional has verified it is safe to enter. Fires may reappear and you don’t want to be stuck in the danger zone. Do not go around police/fire barricades or ignore evacuation orders.
- Do not approach downed power lines or attempt to work around electrical wires.
- If the structure has been significantly impacted and there are any concerns about the structural integrity of the building, do not enter until an expert or structural engineer clears the building.
- Do not enter areas with standing water. There may be hidden dangers in the water.
- Hire a professional fire restoration company—if you can. Talk to your insurance ASAP.
Most of the above comments are about managing dust (fine particulates) and smoke. Smoke smells are more tricky and worthy of a follow up blog. Smoke smells from fires can linger on building materials. Common approaches include applying a liquid-applied vapor barrier over materials or using ozone indoors. There are pros and cons of each approach, and there are other options to discuss. Our advice is to first focus on the dust and tackle the smoke smell next.
Alex Stadtner is President of Healthy Building Science, Inc.