A recent Canadian Centre for Children’s Health evidence review highlights indoor air filtration—both portable air cleaners (PACs) and in-duct HVAC filtration—as an effective public health intervention when outdoor air is polluted by wildfire smoke mdpi.commdpi.com+3researchgate.net+3pubmed.ncbi.nlm.nih.gov+3ncceh.ca.

Review Findings

• PACs with HEPA filters significantly reduce indoor PM2.5 concentrations, often bringing levels down to < 10 µg/m³ even when outdoor levels exceed 100 µg/m³.

• In-duct filtration systems, especially with MERV‑13 or better filters, can also lower pollutant load when HVAC is in active circulation mode.

• Factors influencing effectiveness include CADR rating, room size, placement, and filter maintenance schedule.

Public health bodies recommend PAC use in bedrooms, living rooms, and schools during smoke events, as a low-cost yet meaningful mitigation measure  

Health Impact

Reduced exposure to combustion-derived PM and VOCs lowers short-term cardiovascular and respiratory strain. Studies report fewer hospital visits for asthma exacerbations and fewer symptoms like sore throat, cough, and eye irritation in exposed populations.

Analysis

This review reinforces that air purification is not merely a consumer convenience—it is a health necessity during smoke episodes. HEPA-based PACs, though modest, deliver dramatic reductions in pollutant exposure when strategically placed and used continuously. For vulnerable populations—children, the elderly, individuals with asthma—PACs can mitigate immediate health risks.

From a public policy angle, encouraging PAC deployment in schools, hospitals, and assisted-living facilities during wildfire seasons could form part of resilient emergency planning. Moreover, integrating smart sensors and air quality displays may increase user compliance and awareness.