Wildfire smoke has evolved from an emergency scenario to a predictable, operational risk that facility managers should be prepared to address every year, according to Sissi Liu, CEO of Metalmark, a company providing indoor environmental monitoring and filtration services.
More than 46,000 wildfires have been recorded since the start of the year, with at least 6.3 million acres burned, according to the National Interagency Fire Center.
While the western U.S. works through the consequences of a warm winter and lackluster snowpack from last year’s La Niña, the building “super” El Niño climate pattern is expected to bring hotter and drier conditions to the northern U.S. heading into 2027, NOAA Research Meteorologist Andrew Hoell told the LA Times.
“What that means is much more extreme [conditions] for drought, for other weather patterns, and those could really increase the chances of wildfires,” Liu told Facilities Dive. “We’re seeing this very large macro trend of climate conditions changing. We’ve been talking about this for years now … the reality is we have to start adapting.”
Despite growing attention to the impact of wildfire smoke, much of the scientific research that has been done has yet to be fully translated into the public sphere, Liu said. Many facilities still think they can rely on standard filtration and ventilation systems to protect occupants during wildfire events.
But because of the small, organic particles abundant in wildfire smoke, even with a well-equipped HVAC system and MERV-13 filters, “we have an outdoor source of particles that are consistently infiltrated indoors. There’s a huge concentration [of particulate matter] that the filtration cannot help with,” she said.
Guideline 44, ASHRAE’s guideline for protecting building occupants from smoke during wildfires and prescribed-burn events that was released at the end of 2024, outlines best practices for facility managers to design, operate and maintain systems to reduce health risks from smoke exposure.
“First you have to start by planning. What is your strategy?” said Liu, who contributed to the development of Guideline 44. “These are big questions, but not having them leaves you very vulnerable,” she said.
Key aspects of Guideline 44 point to reducing ventilation during smoke events and having lots of extra filters that can be changed out frequently. “If you shut down the outdoor ventilation, your filter in the central HVAC is still working, but you need to start targeting certain spaces to add air cleaning,” she said. In addition, operators should make sure air cleaners are not set to “auto mode,” because they may not actually sense smaller particles often found in wildfire smoke and, as a result, will sit on a low setting.
“There’s a lot of changes … [and] it’s very confusing to your average person or even building’s facility managers,” she said.
It is critical that building operators get acquainted with their systems and make plans for how to address wildfire events as they become more frequent and regular, according to Liu.
Because many buildings lack the ability to continuously measure conditions, decide what strategies to take and confirm whether interventions have worked, Metalmark recently launched an assessment and operating platform that can be used to translate ASHRAE Guideline 44 into building-specific operational logic.
By connecting indoor monitoring to support decision-making and verifying the impacts of interventions, operators can reduce exposure, maintain operational continuity and manage risk under operating conditions, the company says.
“It’s no longer once in a lifetime or once every 10 years. We’re talking every single year, and the [wildfire] seasons are getting longer,” Liu said. “The mentality can no longer be, because it’s not next to me it’s not going to affect me. It’s frequent, [and] it’s predictable. When you have that, you should have a plan, and you should implement the plan to protect yourself and your loved ones.”
