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Taking precautions: What to do if your home is spared from a fire, but still smells like smoke

Taking precautions: What to do if your home is spared from a fire, but still smells like smoke

We at HypoAir sincerely hope that you and your family have not been forced out of your home by any of the recent wildfires.  Even if your home is spared from fire, if it is in close proximity, danger from lingering smoke particles is a real concern that you should know about and take precautions against.  You may know that smoke is a combination of ultra-fine particles and gasses, both of which can be toxic.  The gasses may be swept away by “airing out” your home or using activated carbon filters, but the particles settle into dust that can be disturbed anytime you clean or even when the HVAC comes on.  

A study was born in the weeks after the Marshall Fire, which occurred in the Boulder area in December 2021.  It spread very quickly and destroyed more than 1,000 homes and buildings.  Those that were near the flames but not burned, like the home of air quality scientist Christine Wiedinmyer, smelled like “the day after a campfire” and had ash on the door and window sills.  (Study finds potentially harmful chemicals lingered in homes affected by Marshall Fire)  Without testing, she did not know whether it was safe for her (or the neighbors who asked) to return to their homes.  So, she became part of a team of expert scientists who tested four homes in the area (including hers) in order to determine what toxins may have been left behind.  

The scientists collected samples of particles of dust in the air and on surfaces in January and February 2022. Elevated concentrations of potentially harmful materials like polycyclic aromatic hydrocarbons (PAHs) were detected in the dust samples.  PAHs are considered carcinogens by the Environmental Protection Agency, and it’s chemicals like these that deserve extra precautions in the way residents return to and clean their homes.  

When the scientists set up their equipment in the homes, they took dust samples from windowsills and used monitors to track particulate matter in the air, minute-by-minute.  The floating particles of ash produced by the fire seemed to settle out of the air in these houses within a day or two, but the dust that Wiedinmyer had seen on her windowsills lingered. In February, the researchers took measurements as a six-person cleaning crew entered one of the homes to vacuum and mop.  The concentrations of particles in the air nearly doubled during that time. Overnight in the same house, the team saw airborne particles spike about once every 20 minutes—likely due to the home's HVAC system switching on and off.  (Study finds potentially harmful chemicals lingered in homes affected by Marshall Fire

For this reason, the scientists recommend wearing a mask when you’re cleaning up fire damage, because human activity like cleaning resuspends the dust in the air, making it easy to breathe in.  Also, be sure to change your HVAC filter more frequently during the first few months after cleanup, and only use true HEPA vacuum cleaners, so exhaust from the vacuum cleaner will not blow dust back into the air.  Wiedinmyer herself “aired out” the home for a week before re-entering to clean.  During this time and going forward, a standalone HEPA filter would be very useful to filter particles that are missed by the HVAC system (if you have one!).  Our Germ Defenders, Mobile Air Angels and Whole Home Ionizers help to ionize and agglomerate dust, making it easier for the filters to trap it.

Another part of the aftermath of wildfires is dealing with contamination to drinking water systems. According to NPR for northern Colorado, The fire damaged six public drinking water systems, and toxic chemicals leaked into pipes from damaged homes and into hydrants where low water pressure created vacuums that pulled the compounds into the distribution system.  Although the personnel in these districts were not all clear on how and where to test, they were eager to do so when experts who had managed similar disaster response teams educated them.  Andrew Whelton, a professor of civil, environmental and ecological engineering at Purdue University, has taken part in several water disaster recoveries, including the 2017 Tubbs Fire and the 2018 Camp Fire in California, the Joint Base Pearl Harbor-Hickam contamination, and a chemical spill in West Virginia.  In a study he co-authored, he said that although the Marshall Fire response was not perfect, major crisis was averted because authorities did not refuse to test.  (Sadly I think many of us can recall other disasters that did not go so well).

There were a couple reasons that contaminants were introduced into these drinking water systems.  First, when a system loses pressure, toxins like wildfire smoke can get sucked into the distribution system.  Second, overheated plastic pipe can leach benzene and other chemicals for months or even years.  According to Whelton’s research, plastic pipes were primed to leach chemicals by temperatures as low as 392 degrees Fahrenheit; wildfires can exceed 1,400 degrees.  Thirdly, flushing out the system quickly with clean water is important to prevent smoke and chemicals from reaching damaged pipe, which can act as a reservoir for such toxins.

If your home survives a fire in the future, remember that unseen dangers like carcinogens may still linger and you need to take caution with your air and your drinking water.  Although it seems that authorities in the Boulder area were for the most part very proactive for public health during the Marshall Fire response, it’s usually up to individual residents in wildfire-prone areas to have stores of masks, filters and clean drinking water.  We hope you don’t have to go through such a catastrophe, but it certainly doesn’t hurt to be prepared.

Photo by Egor Vikhrev on Unsplash

Fire and Smoke Recovery

Fire and Smoke Recovery

Wildfires have been very destructive in the western half of the US in the late 2010's and early 2020’s.  As for the future, a 2022 report by the UN Environment Programme (UNEP) and GRID-Arendal projects an increase in extreme fires by 14% by 2030, 30% by the end of 2050, and 50% by 2100, due to climate change and land-use change. (breezometer.com)  

Fire disasters, like natural disasters, do not just destroy what the fire touches.  They can disrupt major infrastructures like highways and railways, power and water, and most important, air quality.  Because fires may smolder for some time, try to prepare to deal with the effects for weeks. 

If you live in an area prone to wildfires or prevailing winds that may carry smoke, here are some ways to prepare:

  • Seal doors and windows with weatherstripping, caulk and door sweeps.  
  • Find out how to adjust your HVAC system accordingly: you’ll want to close the fresh air intake and change over to recirculation, no matter whether you have central AC, a window air conditioner or portable air conditioner.
  • Purchase extra MERV 13 or higher filters for your HVAC system, to be used on poor air quality days.
  • If you live in an apartment building or condo with little control over the HVAC, consider purchasing vent filter material so you can place them in the vents into your space. Carbon vent filter material will neutralize many VOCs as well.
  • Purchase a HEPA air cleaner (non-ozone producing type) and be sure to have an extra filter or two on hand.    
  • Keep a number of N95 respirator masks on hand.    
  • Keep canned food and bottled water on hand.
  • Stock up on essentials for cleaning smoke odor: baking soda, white vinegar, rags, TotalClean


  • Try not to cook during a wildfire emergency, because cooking indoors increases small particulates and vapors in the air, and you won’t want to turn on your stove exhaust, as that will draw polluted outdoor air into the house.  Try to use just the canned food you have on hand.
  • Monitor the filters in your HVAC system and air purifiers and change them when you start to notice a color change on the front of the filter, or when the output air starts to smell like smoke. 
  • Check your local air quality and receive updates from airnow.gov . Fire and smoke maps are available under the heading fire.airnow.gov.  You can also register for a free 14-day trial of Breezometer’s Air Quality app.  Below is a diagram to understand air quality index values (airnow.gov).
  • Use N95 respirators to evacuate to a safer place if necessary.  

Source: airnow.gov


  • Don’t open windows and doors until the air quality index is less than 100.  When that happens, you can open windows fully to get more fresh air ventilation. 
  • Set up fans near doors and windows to “push” smoke odor and soot outside.

To remove smoke odor that infiltrated from outside, or if you had a fire in your home:

  • Run air purifier(s) continuously with charcoal filters. 
  • Sprinkle baking soda over carpets and rugs and leave it overnight.  Then using a vacuum with HEPA filter, vacuum out the carpets.  
  • Remove drapes, towels, and any hanging fabric exposed to smoke, and either launder it in your washing machine or send it for professional cleaning.  When washing it yourself, you can add a cup of distilled white vinegar to your regular laundry detergent to remove smoke.  Don’t machine dry the item until the odor has been removed; it may need an additional washing cycle.
  • Wipe down all hard surfaces, including walls, ceilings, floors and windows with TotalClean or a 1:1 mixture of warm water and white vinegar (TotalClean is more gentle than vinegar and can be used on stone, wood, etc.)  Dispose of rags or wash them out with mild detergent and water as you go.  

To clean fabric-upholstered items:

  • Try to remove any cushion covers that are washable.  
  • Clean bare foam cushions by using “air replacement”:  Place the cushion into a large vacuum-seal bag and sprinkle baking soda over it.  Seal the bag and use your HEPA vacuum to remove the air from inside the cushion.  Let the air back into the bag to re-inflate the cushion.   Repeat several times if necessary. 
  • Sprinkle baking soda over the piece and let it set overnight before vacuuming it off.
  • You can also move the piece outside to air it out in the sun.  
  • It’s difficult to remove smoke that’s settled into furniture, however, if it does not dissipate following using an ozone generator, you can contact a restoration company for their services if it’s a valuable piece to you.

Try an Ozone Generator to remove smoke odors:

  • Ozone generators should only be used once all surfaces that can be cleaned are thoroughly cleaned (walls, floors and ceilings too!).  
  • Ozone is not as effective in areas of high humidity, so running the air conditioner or a dehumidifier in the space to get the humidity down (60% or less) is advisable.  Central air conditioning and any exhaust fans must be shut down when using the ozone generator, though, because you’ll want the ozone to stay in the space. 
  • Use fan(s) within the space to circulate the ozone.
  • Ozone generators cannot be used in the presence of people, pets or plants, but once these are removed, they can be quite effective in removing smoke.  Follow all instructions to seal up the space and allow it to work for the full time advised before ventilating.  Contact HypoAir regarding rental of our ozone generators, or local restoration companies may rent ozone generators.    

For large areas with open walls and ceilings such as basements, garages or gutted homes, consider having them soda blasted by professionals to remove soot and smoke odor from the structure in hard-to-reach places.  Baking soda’s legendary cleaning and odor-absorption qualities can produce amazing results when combined with commercial equipment and a skilled contractor.


  • Spray deodorizers or fresheners to “cover up” the smell of smoke, because they do nothing to remove the contaminants, and many have toxic ingredients in them.
  • Attempt to live in spaces with heavy smoke damage until they are cleaned.  “Third-hand smoke” is the term used for the way carbon and chemicals in the smoke react to the materials in your home, and it can make you very ill.
  • Neglect flood remediation if the smoke damage was part of a fire in your home and fire response crews extinguished it using water.  Building materials must be removed or dried thoroughly within 48 hours in order to prevent mold growth. 

Photo by Daniel Tausis on Unsplash

Spread the warmth from your fireplace…not the air pollution!y

Spread the warmth from your fireplace…not the air pollution!

With temps turning colder and guests coming over for the holidays, I thought to myself, wouldn’t it be nice to start a fire in the fireplace soon?  With Thanksgiving a week away, I decided to make sure that it would be a joyful experience and not a regret!  Here’s some tips for getting your fireplace and wood ready.

The fireplace:

  • If you haven’t had the chimney cleaned in several years after using it, call a professional for this job and make sure they use HEPA filters in the vacuum.  
  • If you are not having your chimney cleaned (if so the cleaner can do this check), check that the damper is working properly:  Get some safety glasses on and a flashlight for this one.  Moving your head underneath the fireplace opening, use the lever handle to open the damper and make sure it stays open when you release it.  Hopefully you do not have the surprise of wildlife or a lot of debris being released when you open it!  Close it again until you get ready to start the fire, making sure that it closes fully and seals (see next point).
  • Sealing the fireplace damper when the fireplace is not in use is really important.  Inadequately sealed fireplaces are noted as being one of the worst air leakage sources in the home. According to the D.O.E.3, by weatherstripping the fireplace, the typical U.S. home can reduce air leaks by 14% or more. (hearth.com)  Here some ways of sealing your chimney, some of which would be better avoided:
    • Top mounted chimney dampers don’t seal the chimney space off from your home, meaning that the combustion products and cold (or warm) brick is still exposed to your air.  These aren’t highly recommended.
    • Plugs are inflatable devices that seal off the chimney when it’s not in use.  The problem is that they can deflate with colder temps, allowing air to leak through, causing it to need to be reinflated sometimes.  Sometimes the product itself leaks. 
    • Glass doors don’t adequately seal off the chimney, even though they look nice.  The solution: a magnetic, insulated cover will stop the drafts if your fireplace doors are sealed to the masonry.
  • A grate is really helpful to help your fire burn cleanly and not smoke too much.  Why?  A grate gets the wood up off the floor and allows air to circulate under and through the logs.  (This is the key to those new smokeless fire pits–air holes along the bottom of the fire pit get adequate combustion air to the wood!)  Check that your grate is sturdy.  If it is corroded or broken, take it to a welding shop for repairs.  You don’t want a pile of logs shifting and rolling or throwing a cascade of sparks when you’ve already started your fire!

The wood:

  • Only burn wood that is completely dry, which usually means it was cut and stored over 6 months ago.  Only burn hardwood,
  • Don’t buy firewood a long distance from your home.  Although it may look clean and dry, wood that is harvested over 50 miles from your home may have species of pests (eggs and insects) that are new to your area and by transporting them, you could unleash an invasive pest to the trees in your county. (Forestry Commission
  • Be selective about what kind of wood you burn indoors.  Stay away from wood with a lot of resin, such as pine and spruce, because burning it forms creosote that can cause a chimney fire.  Never burn treated wood or particleboard, as these release toxic fumes. (Family Handyman)
  • It's important to store all firewood outdoors until you're ready to use it, because firewood will naturally have some mold on it.  Storing it outdoors not only keeps the mold spores from entering your home but it also reduces the risk of spiders, ants and other unwanted insects from coming inside as well.  (firewood-for-life.com)
  • If you encounter wood with a lot of visible mold, it’s best not to bring it inside at all!  If the mold is on the bark, you can try to knock the bark off with a hatchet or hammer.  Remember, mold spores spread easily through the air and disturbing a mold colony just by moving the firewood (and stacking and then tossing it into a hot fireplace) will release millions of spores into your home!

What about firestarters?

  • Firestarters are easy to buy at the hardware or grocery store, but it may be harder to determine if their ingredients are safe and non-toxic.   In a 2014 study, burning synthetic firewood logs increased breast cancer risk in women by 42%.  Wood and synthetic logs are sources of polycyclic aromatic hydrocarbons (PAHs), which cause mammary cancer in animal experiments. Both contribute to residential air pollution, but researchers found that only the synthetic logs were found to be associated with an increased risk of breast cancer.
  • If you have any concern, take the safe route and make these firestarters easily from cardboard egg cartons, wax and sawdust (great project with your kids!)  The only caveat I would add is not to use just any candles for wax; paraffin candles are made from petroleum products, and soy candles are from hydrogenated oils that usually contain some paraffins.  If you can find it, unscented beeswax is the best!

Test it out! 

  • Keep a fire extinguisher nearby.
  • First and foremost, make sure the damper is open and any plugs or stops are removed before starting a fire.  Use your safety glasses when looking up into the chimney!
  • Always clean out cold ashes from a previous fire before starting a new one.  If you use your fireplace frequently, an ash vacuum is really helpful and speeds up the job.  Don’t use just any vacuum to suck up ashes, as vacuums without a HEPA filter will blow them all over the room!
  • Prime the flue: this means getting a flow of air going up the chimney.  The cleanest, simplest way is use a hair dryer on the hot setting, or a blow torch: just hold and point it up the flue for a few minutes. 
  • Place a few firestarters or balled up newspaper under the grate and some kindling (small pieces of wood) on the grate.  Start the fire with a long-handled igniter. 
  • When the kindling is burning well, place a few logs on the grate.
  • Does your fireplace smoke? (does smoke roll out of the top of the opening into the room?)  If so, the opening may be too large in relation to the flue, causing air to stall at the top of the firebox and allow smoke to come out into the room.  Here is a great video explaining the concept and how to fix it (or buy the right smoke guard and screen if you’re not a welder).  A smoke guard is a strip of metal that extends from the top of the opening down into the fireplace 4-8” to make the opening smaller and improe draft.  This article tells about an aluminum foil trick on how to size the smoke guard before you buy one, plus other reasons the fireplace may be smoking.
  • If there’s no smoke coming into the room, add more logs slowly, making sure to place them with good air flow from below. 
Fireplaces are not the cleanest or most efficient ways to heat your home, but the fireplace is here to stay in American homes because of its tradition and ambience.  For more tips on upgrading its efficiency, check out our other post on fireplaces here.  We wish you warm and cozy memories snuggled in front of your (safe, clean-burning) fireplace!