Remediation of indoor environments impacted by wildfire smoke: A review of available information and research needs

There is growing interest in better understanding wildfire smoke contamination in the indoor environment, the associated human exposures and health impacts. Most efforts have been devoted to developing guidelines protecting occupants during a wildfire event, e.g., on the proper use of building ventilation and filtration. However, there is also a need to understand the long-term impacts of wildfires on indoor contamination, and which are the most effective mitigation options. We reviewed the scientific literature and additional available documentation to identify the main chemical contaminants found in buildings impacted by wildfire smoke. Polycyclic aromatic hydrocarbons (PAHs) and trace metals have been reported on indoor surfaces and dust after exposure to smoke, and are of particular concern due to the health effects associated with continuous exposures. Described mitigation approaches included cleaning using dry and wet media, vacuuming and ozonation. While little information is available on their effectiveness in long-term removal of wildfire smoke contaminants, similar remediation methods have been described to remove other types of persistent contamination indoors, including thirdhand tobacco smoke and mold, providing a reference to predict the expected efficacy and limitations of those methods. Gaps in the available information and research needs were identified to develop a research agenda addressing wildfire smoke’s persistent contamination and mitigation options.