Outline:
The dangers of wildfires never stop even when the fire is gone, as the ongoing danger could endanger thousands.
Last year, severe wildfires swept across Europe, consuming over a million hectares of land. This figure is four times the area affected in 2024 and covers a region bigger than the entire island of Corsica.
Over 1,800 forest fires were reported, releasing more than 38 million tonnes of CO₂. Severe wildfires in Portugal and Spain contributed to more than two-thirds of the damage across the EU, with experts stating that climate change increased the likelihood of such events by 40 times.
Currently, experts caution that once the fires have been put out, people who go back to their houses might still face dangers from exposure to recognized cancer-causing substances.
The aftermath of wildfires
A recent research, released in Environmental Science and Technology Letters, examined the effects of the 2025 Los Angeles County Wildfires, which led to the destruction of over 18,000 residences, caused the death of at least 31 individuals, and resulted in approximately 200,000 people being displaced.
On the second day of the fire, scientists began gathering air samples both inside and outside. They kept up the collection during the time after the fire, finishing their on-site work on 18 February – 18 days following the extinguishing of the fires.
Following an analysis of the samples, researchers discovered that the concentrations of volatile organic compounds (VOCs) were notably higher after the fire had occurred than during the active burning phase. These were especially noticeable inuninhabited homesinside burn zones, indicating continuous indoor emissions from materials affected by smoke.
How harmful are VOCs?
Contact with VOCs like benzene, toluene, ethylbenzene, and xylenes (BTEX) has been associated with various health issues, from temporary irritation to cancer and organ harm. Nonetheless, this varies based on the level of exposure, how long it lasts, and a person’s personal sensitivity.
Indoor levels of VOCs may reach up to ten times the concentration found outside, as reported by the American Lung Association. These substances are commonly present in everyday household items like cleaning sprays, paints, and solvents.
“Several of these are carcinogenic and unquestionably detrimental to human health,” states Yifang Zhu, a professor in the environmental health sciences department and one of the study’s co-authors.
The main issue with these urban wildfires was the danger posed by the smoke’s toxicity, as VOCs are commonly found in homes, coming from things like construction materials and everyday items such as cooking and cleaning products.
The research suggests that frequently opening windows, using central heating, ventilation, and air conditioning systems equipped with filters that have a Minimum Efficiency Reporting Value (MERV) of at least 13 can assist in lowering exposure to volatile organic compounds. Employing air purifiers with charcoal filters may also be beneficial.