Wildfire smoke does not need to reach a property directly to damage it, according to Jim Mandeville (pictured), senior vice president at First Onsite Property Restoration, who said homeowners and businesses hundreds or even thousands of kilometres from an active fire routinely underestimate the risk to their buildings.
The concern comes as new survey data from First Onsite found 63% of Ontarians are concerned about wildfire smoke, a 10-point increase year over year, as smoke from hundreds of active wildfires across Canada has repeatedly pushed Southern Ontario's air quality among the worst in the world.
Mandeville said the danger to property is easy to miss because the visible signs look, at first, like ordinary dirt rather than smoke contamination.
"You end up with soot deposits on the house, on the outside, and people, because they're not used to this, go, oh, well, the house is dirty," Mandeville said. "Yes, but it's soot from the wildfire."
Left untreated, that soot can cause lasting damage well beyond a dirty exterior, Mandeville said. White vinyl windows can yellow, glass can become pitted, and furnace filters can become clogged, all from material carried in from a fire that may be far outside the city.
"That material is still being carried in the air and still being deposited," Mandeville said, even when a property sits 1,500 or 2,000 kilometres from the fire itself.
Businesses face a distinct version of the same problem, Mandeville said, one that goes beyond property damage into liability. If smoke infiltrates a workplace to the point that indoor conditions resemble what is happening outside, employers may be creating an unsafe environment for staff without realizing it.
"If the inside of your facility looks like outside on one of these smoke days, there's a potential that you're creating an unsafe work environment, which is pretty scary from a liability perspective," Mandeville said.
In response, Mandeville said he is seeing two distinct approaches from businesses that take the risk seriously. Some are investing in upgraded HVAC systems with better filtration built in permanently, while others bring in temporary air purification equipment during prolonged smoke events rather than making a permanent infrastructure change.
The most common mistake Mandeville sees, however, is neither of these responses, but simple inaction, continuing everyday habits as though nothing has changed outside.
"They keep doing all the things they did before it got smoky outside," Mandeville said. "They go to bed and they open their window. They decide that it's not that hot today, and they open all the windows. They wedge open all their doors in their warehouse because they decided that they didn't need to invest in air conditioning."
Once soot is visibly present inside a home or business, Mandeville said the second common mistake is assuming it can be handled with routine cleaning. In reality, he said, professional remediation of a home with visible soot contamination can involve five to ten workers over a full day, or longer for more severe cases.
"When we come in, and we clean a home that's got visible soot in it, you could be talking five or 10 people cleaning in there all day in a long shift for potentially a week or two," Mandeville said. "That's not something your average homeowner has the time, skill, expertise or money for."
Commercial properties present an even larger version of the same challenge, Mandeville said, simply because of scale.
First Onsite's own guidance for homeowners and businesses during prolonged smoke events includes arranging a professional inspection, since contamination can spread into hidden areas that require specialized equipment to detect, and checking residue on surfaces such as windows: light brown dust is typically ordinary household dirt, while grey or black residue may indicate smoke contamination requiring professional attention.
Mandeville said the underlying pattern, whether at a home or a commercial building, is the same regardless of distance from the fire itself.
"It's just like being beside the fire," Mandeville said, "even though you're 15 or 1,500 or 2,000 kilometres away."
