What you need to know about wildfire smoke in homes

When wildfires spread through neighborhoods, they burn all kinds of materials found in cars and homes and everything around them—electronics, paint, plastic, furniture.

Research shows that the mix chemicals are released when the combustion of man-made materials such as these is different and potentially more toxic than that spread during a vegetation fire. Smoke and ash blow under doors and around windows in nearby homes, bringing absorbed chemicals onto furniture, walls and other indoor surfaces, and continue to fumigate for weeks and months.

As people return to smoke-damaged homes after wildfires, there is they can take a few steps to protect their health before starting to clean.

High levels of metals and VOCs

In 2021, after the Marshall Fire engulfed neighborhoods near Boulder, Colorado, my colleagues at Colorado universities and labs and I heard from many residents concerned about ash and ash. persistent odors in their homes had otherwise survived the fire.

My colleagues found it in homes that they could quickly test high levels of metals and PAHs – polycyclic aromatic hydrocarbons – in ash. We also found high VOCs – volatile organic compounds – in the air samples. Some VOCs, e.g dioxins, benzene, formaldehyde and PAHscan be toxic to humans. Benzene a a known carcinogen.

At that time, we could find no information on the physical health effects of people returning to smoke-damaged homes after a wildfire. So we look for examples conducted a survey among residents affected six months after the fire, one year and two years after the fire.

Even six months after the fire, we found it many people have reported symptoms corresponding to the health risks associated with smoke and ash from fires.

More than half (55%) reported experiencing at least one symptom six months after the fire that they attributed to the Marshall Fire. The most common symptoms were itchy or watery eyes (33%), headache (30%), dry cough (27%), sneezing (26%), and sore throat (23%).

All of these symptoms, as well as a strange taste in the mouth, were associated with people reporting that they smelled different when they returned home a week after the fire.

Most of those surveyed said that the odors have diminished over time. Most people attribute odor improvement to the passage of time, cleaning surfaces and air ducts, changing furnace filters, and removing carpets, textiles, and furniture from the home. However, many still had symptoms.

We also found that living near large numbers of burned structures was associated with these health symptoms. We found that for every 10 additional destroyed buildings within 820 feet (250 meters) of a person’s home, there was a 21% increase in headaches and a 26% increase in bad taste in the mouth.

These symptoms overlap with what would be expected without exposure to the chemicals we found in the ash and measured in the air. we were able to learn about smoke damaged houses in depth.

Persistent symptoms and questions

There are still many unanswered questions about the health risks of smoke and ash damaged homes.

For example, we don’t yet know what the long-term health consequences might look like for people living in a house with persistent gases from fire smoke and ash. We found it significant population decline reports symptoms one year after the fire. However, 33% of people whose homes were affected and who responded to a follow-up survey still reported having at least one fire-related symptom. About the same percentage reported having at least one symptom two years after the fire.

We also could not measure the level of VOCs or metals that each individual was exposed to. However, we think that reports of a person’s house smelling a week after a fire changing demonstrates the possibility of VOCs in the home. This is likely to affect the health of people whose homes are exposed to smoke or ash from wildfires.

Tips for protecting yourself after wildfires

Forest fires houses and other buildings are burning more and more as more people move rural-urban interface, temperatures rise and fire seasons are lengthening.

Here are some if your home survived a wildfire nearby steps to think about before you start cleaning:

• When you’re ready to clean your home, start protecting yourself. At least wear an N95 (or KN95) mask and gloves, goggles, and clothing that cover your skin. Cleaning can send some of those gases and ash back into the air.
• Keep people with heart or lung conditions, the elderly, pregnant women, children and pets away from cleaning activities.
• Vacuum the floors, curtains and furniture. Recent scientific research how documents cleaning all surfaces can reduce reservoirs of VOCs within a home and reduce indoor air concentrations of VOCs. After the air outside has cleared, open the windows to let fresh air in.
• Avoid harsh chemical cleaners as they can react with the chemicals in the ash.
• To prevent further spread of ash, clean your HVAC filter and ducts and replace the filters monthly until the odor is gone. Portable air purifiers with carbon filters can help remove VOCs and particulates.
• If your car smells like smoke, consider changing the cabin air filter.

This is an update to this article first published on December 23, 2024.

Colleen E. Reidassociate professor of geography department, University of Colorado Boulder

This article is being republished Conversation Under Creative Commons license. read it original article.