Wildfire smoke is a complex mixture of pollutants that can impact communities near and far from the fire. One of the most harmful constituents is fine particulate matter (PM2.5), which causes respiratory and cardiovascular problems, as well as neurological effects, endocrine disorders, and other adverse health outcomes. For most people who don't work outdoors, exposure to wildfire smoke occurs primarily indoors. In the U.S., people spend on average about 90 percent of their time indoors, and during wildfire smoke episodes a core public health recommendation is to stay inside and take steps to keep smoke out.
Air filtration is a key strategy for limiting indoor exposure to wildfire smoke. Having air filtration capable of removing dangerous pollutants not only makes buildings more resilient to future wildfire smoke episodes but also reduces exposure to vehicle and industrial pollution and to contaminants or infectious aerosols generated inside the building. In addition to filtration, air sealing can help reduce the entry of wildfire smoke and other outdoor pollutants, and ensuring safe indoor temperatures allows people to stay indoors during wildfire smoke episodes and heat emergencies.
Overview of the Report
This report discusses state policy approaches for reducing indoor exposure to wildfire smoke, including notable policies in western states that were established in the few years prior to the report’s publication in 2024. While preventing and limiting wildfires in the first place is an important means of reducing the health impacts of wildfire smoke, the report focuses on preparing for and responding to the smoke that is produced by wildland fires. The highlighted state examples illustrate the following key strategies.
Interagency Coordination and Emergency Planning. Given the large number of agencies involved in wildfire smoke planning and response, formal and informal mechanisms for interagency collaboration are essential. Statewide wildfire smoke plans or protocols, updated periodically, can help clarify agency roles and responsibilities. States can also establish policies that require or facilitate wildfire smoke planning at the local level.
Information, Outreach, and Education. In order for people to protect themselves from wildfire smoke, they need clear and practical information about health risks, air quality conditions, and evidence-based actions for reducing exposure. Outreach and notification are also needed in advance of and during prescribed burns, so that affected communities can avoid anticipated and unexpected smoke impacts.
Cleaner Air Centers. Cleaner air centers make use of existing facilities that are open to the public for portions of the day to provide relief from wildfire smoke. State assistance is important for supporting the local agencies and organizations that set up and operate cleaner air centers. Comprehensive written guidance is also needed – on both the technical approaches to reducing indoor smoke levels and the considerations for providing outreach, transportation, and other measures to reduce practical barriers to accessing and using the facilities.
Material Assistance. State funding is needed to assist people who are not in a position to obtain the air filtration or air conditioning needed to create clean spaces in their homes. States can develop new programs focused directly on addressing wildfire smoke exposure, as the Oregon legislature did in funding state distribution of air filters and air conditioners. Alternatively, states can expand or leverage existing healthy homes, asthma control, energy efficiency, Medicaid, and utility assistance programs. Many states already have these types of programs in place and could identify how they might be used to help prepare homes for reducing wildfire smoke and other indoor environmental risks.
Regulatory Requirements. Several areas of state regulatory authority are relevant to reducing indoor wildfire smoke exposure in homes, schools, workplaces, and other buildings. Jurisdictions can incorporate a requirement for high-efficiency filtration in the next revision of their building codes and in other state laws and rules governing construction of publicly-funded buildings like schools and affordable housing. States can also require those who operate existing rental housing, schools, child care facilities, and workplaces to develop and implement wildfire smoke emergency plans and take specific steps to ensure their buildings provide adequate filtration and cooling.
As the national Wildland Fire Mitigation and Management Commission underscored in its 2023 report, there are “inequities in people’s vulnerability to smoke and ability to mitigate its impact that have not received sufficient attention and support.” State regulatory measure are important for ensuring that all residents are protected from wildfire smoke, and non-regulatory programs should be designed to reach people who are at heightened risk from wildfire smoke exposure and those who have been historically underserved by government programs and policies.
Explore other materials from ELI’s Indoor Environments Program.
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