Building ventilation and wildfire smoke
July 7, 2025
Now that wildfire season has arrived, many members of the UAF community have been asking why they can smell smoke inside campus buildings and why the buildings’ HVAC systems don’t eliminate the smell.
Most campus buildings are ventilated using systems that "condition" outdoor air. Large supply fans pull in fresh air, filter it through MERV-rated filters, and then heat or cool it based on the season. While the filters are effective at removing many particles, including dust, pollen and ash, they are not designed to eliminate the smell of wildfire smoke.
A common question is whether it’s possible to shut off the air-handling systems to keep smoky air out. Unfortunately, doing so would quickly make indoor spaces hot and stuffy. That additional heat is unpleasant for building occupants and could cause damage to sensitive equipment that requires stable temperature control. Without air handling in laboratory buildings, things like fume hoods would create negative pressure, pulling even more smoky air in through doors, cracks and other openings.
The best approach during smoke events is to optimize the percentage of outdoor air coming into a building, while continuing to circulate and filter indoor air. While it’s not possible to remove all of the smoke odors, this strategy strikes the best balance between air quality, temperature control and energy efficiency.
The Facilities Services team appreciates the UAF community’s understanding as they navigate these environmental challenges. The team is aware of the smoke; calls to the Facilities Services dispatch are not necessary. Crews will continue to adjust air handling in buildings around campus until wildfire smoke dissipates.