Wildfire Season is Here: Learn How to Stay Safe and Healthy

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Jul 3

Orange sky in San Francisco due to the west coast wildfires. — San Francisco, California | Photo Credit: Thom Milkovic

Insights from the Center for Active Design Experts

Safeguarding IAQ from Wildfire Smoke

Last July, Canada experienced a severe wildfire season that blanketed much of Canada and the United States with hazardous smoke. This year, Canada faces similar conditions, and there are currently several wildfires raging in the country’s northwestern regions causing air quality issues in four US states. Wildfires not only pose a threat to life and property, but also endanger health due to wildfire smoke, primarily from fine particulate matter, or PM2.5. Exposure to PM2.5 can adversely affect lung and heart function and irritate the eyes, lungs, and throat. It can also exacerbate existing conditions such as asthma, chronic obstructive pulmonary disease (COPD) and heart disease, especially for vulnerable populations such as children, pregnant women and older adults. Given that this health hazard is linked to climate change and expected to worsen across North America, proactive preparation for potential poor air quality during wildfire season is crucial.

Keeping Your Air Clean in Commercial Buildings

Due to the ongoing threat of wildfire smoke, municipalities and government agencies are making preparations and updating public guidance to improve their smoke preparedness. There are several best practices that can be implemented before and during a wildfire to limit smoke exposure and safeguard health, and these can be tailored to each unique environment.

For commercial buildings and schools that use HVAC systems with air handling units that bring outside air into buildings, the following IAQ practices are recommended:

Prepare a smoke readiness plan. The US EPA and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommend preparing a 10-step smoke readiness plan to protect occupants. The key steps are summarized below, and additional detailed guidance is available in this online resource.

Purchase wildfire preparedness supplies such as N95 masks, extra filters, and portable air cleaners.
Upgrade to MERV 13 or higher (or HEPA) filters by first evaluating the building’s capacity to operate with upgraded filters, then completing installation.
Conduct a full maintenance check on the HVAC system and make necessary repairs.
Assess and maintain adequate air flows to protect occupant health and equipmen.t
Prepare to add supplemental filtration at the intake air vent.
Assess filter conditions by adding a port or pressure gauge to measure the filter pressure drop on at least one air-handling unit.
Limit smoke intrusion by weatherizing the building using methods such as sealing and caulking cracks.
Prepare to monitor indoor particulate matter levels by purchasing low-cost air monitors and placing them away from indoor sources of PM2.5.
Create temporary cleaner air spaces within the building using air cleaners and PM2.5 monitors.
Anticipate and reduce sources of indoor PM2.5, such as cooking, vacuum cleaning, use of printers or copiers and smoking.

Decide which conditions warrant implementing the plan. If conditions are currently smoky, or the coming days are forecasted to bring wildfire smoke, it is recommended to begin implementing the plan, depending on building-specific feasibility. ASHRAE provides a decision matrix to assist building managers when planning for wildfire season.
Implement, monitor and adjust. Building operators and HVAC professionals can reference the detailed checklists available at this link as they prepare the building for smoke, test the HVAC system, and monitor indoor particulate matter concentrations in the event of wildfire smoke. Further resources are available for buildings that require balancing wildfire smoke protection with the needs of contagious disease control as well as those equipped with outdoor air economizers for energy conservation.

Best Practices for Residences and Single-Family Homes

In addition to the guidance available to commercial building operators, researchers and government agencies have recently published strong recommendations to ensure that the air quality in our homes remains healthy in the event of wildfire smoke exposure. These are designed to balance the needs for keeping polluted air out of a building while also maintaining cool indoor temperatures during summer months:

Minimize outdoor air intake. During the summer months, we often keep windows open to let in fresh air and cool our spaces; however, in the event of wildfire smoke, it is important to shut windows and doors and instead use fans and air conditioners to stay cool. If your home has a central AC, set it to recirculate instead of intaking fresh air.

Manage air conditioning needs. Note that single hose air conditioners that vent through an open window can pull in smoke, so it is important to use in-window air conditioners with the damper closed instead. For residences with evaporative coolers, avoid using evaporative coolers in smoky conditions. Use cooling options such as fans if there are no ways to filter smoke out of air conditioned air, and if it is not possible to stay cool without drawing in outdoor air, the EPA recommends sheltering elsewhere. When that isn’t an option, using or making portable air filters is a good temporary alternative.
Use portable air filters or consider making DIY filters. The EPA has informative resources on selecting portable air filters; these should be sized for the rooms treated and they should not generate ozone, which is another pollutant that can worsen indoor air quality. If commercial filters are not available, DIY filters with a box fan can be used temporarily to clean the air.

Mitigating and Adapting to Climate Change Resilience

Researchers forecast that the threat of wildfire damage and smoke exposure across North America will increase throughout the coming century, driven by rising temperatures caused by climate change. In order to ensure occupant health while preparing for climate resilience, we encourage readers to stay abreast of effective ways to stay prepared for wildfire season and keep our indoor air clean. In addition to the building strategies reviewed above, it is critical to follow local AQI readings, avoid heavy physical activity, and use N95 respirators when going outside in wildfire smoke.

The Center for Active Design’s focus on heat-related mitigation strategies, including ones that safeguard people from wildfire smoke, is reflected in the most recent Fitwel Standard, v3. To learn more about our broadened evidence base and how the v3 strategies account for ripple effects of climate change, including wildfires, click here.

Article contributed by Skyler Chin of the Center for Active Design Research Team.

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