Evaluating Indoor Air Cleaning Effectiveness During Wildland-Urban Interface Fire Events: Insights from a Controlled Residential Study
NATHAN LIMA, Aika Davis, Michael Link, Thomas Cleary, Ryan Falkenstein-Smith, Rileigh Robertson, Steven Emmerich, Dustin Poppendieck, National Institute of Standards and Technology
Abstract Number: 455
Working Group: Control and Mitigation Technology
Abstract
Smoke from Wildland-Urban Interface (WUI) fires threatens indoor air quality, necessitating effective mitigation strategies for protecting public health. This study addresses critical knowledge gaps regarding the performance of portable air cleaning technologies during WUI smoke events through a comprehensive measurement campaign conducted at NIST's Indoor Air Quality test house. Ten controlled WUI surrogate burns were performed, and varying parameters were used, such as the number of identical portable air cleaners deployed, filter Minimum Efficiency Reporting Value (MERV) rating, filter condition, and room compartmentalization strategies.
Aerosol measurements were conducted using various instruments, including Optical Particle Counters, a nephelometer, and a Differential Mobility Analyzer. Results demonstrate variability in measured Clean Air Delivery Rates (CADRs) between instruments, with mean CADR per portable air cleaner values ranging from 140 ± 24 m³· h^-1 to 510 ± 73 m³· h^-1 for PM₁ across different burn configurations. Spatial heterogeneity was observed between kitchen and bedroom measurements, highlighting the importance of multi-point sampling. The deployment of portable air cleaners reduced indoor particle concentrations, with four portable air cleaner configurations showing the most rapid decay rates (up to 6.7 ± 0.15 h^-1). Notably, MERV 12A filters provided comparable or slightly higher CADRs than MERV 13 filters for ultrafine and fine particles, suggesting that filter airflow resistance plays a role in overall system effectiveness.
The findings highlight the importance of instrument selection, measurement location, and consideration of particle size fractions when evaluating indoor air cleaning interventions during WUI events. The study provides insights into the effectiveness of different filtration strategies and demonstrates that combining compartmentalization with localized filtration can achieve exceptional particle removal effectiveness. These results have implications for developing practical indoor air quality protection strategies and reducing indoor-associated WUI health risks.