Back to School in BC: Why Clean Air Matters More Than Ever

As students across British Columbia return to classrooms this September, many schools are facing a persistent—and potentially hazardous—guest: wildfire smoke. With nearly 155 active wildfires burning across the province and over 50 considered “out of control,” Metro Vancouver and much of BC are under severe air quality alerts, including Environment Canada’s “worst possible” rating as of September 3, 2025. The 2025 wildfire season has become Canada’s second-worst on record, with smoke drifting far and wide across communities.

Why Schools Must Prioritize Indoor Air Quality

• Vulnerability at the start of the school year: Children spend much of the day indoors, making classroom air quality critically important—especially when outdoor air is filled with PM₂.₅ and microscopic pollutants.
• Shielding students while learning continues: Schools equipped with effective air filtration systems can offer safer spaces during smoky days, whereas poorly filtered environments may exacerbate asthma and other respiratory issues.
• Long-term resilience: This wildfire season is not an anomaly. Experts warn of increasingly frequent "smoke days" and urge schools to build infrastructure capable of protecting students during these recurring emergencies‍.

HEPA Filters & MERV 13: Why They're Not Enough by Themselves

MERV 13 and the Limits of HVAC

• Partial protection only: MERV 13 filters capture about 85% of particles ≥ 1 µm and just 50% of those ≥ 0.3 µm. Wildfire smoke often includes particles well under 1 µm, slipping through the filter’s net.
• Efficiency may degrade quickly: HVAC filters with charged media—common in many systems—can rapidly lose effectiveness against smoke particles, even within minutes of exposure. This calls into question whether MERV ratings accurately hold up during smoke events.

True HEPA: Small-Scale, High-Efficiency, Yet Limited

• High capture rates, but tradeoffs: HEPA filters can trap 99.97% of particles ≥ 0.3 µm—but that efficiency comes at a cost. High airflow resistance limits their use in many HVAC systems, and they're more practical as standalone purifiers for small spaces, like individual rooms‍.
• No gas or odour filtration: HEPA filters don’t remove gaseous compounds or volatile organic compounds often present in wildfire smoke. You’d need additional activated-carbon media for those.
• Maintenance-dependent performance: If not replaced regularly—ideally every six months—HEPA filters suffer bypass and clogging, decreasing their efficacy over time.

Recommendations for Schools This Fall

1. Upgrade HVAC Where Feasible‍

Use MERV 13 rating or higher. Conduct maintenance checks, assess airflowcapacity, and consider building-specific “Smoke Readiness Plans” as recommended by BC Wildfire Management Strategies.

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2. Prioritize Portable Cleaners‍

Deploy DFS (Disinfecting Filtration System) air purifiers in smaller orhigh-priority spaces, provided the room’s airflow supports their use. Theseunits offer higher efficiency than standard HEPA by targeting ultrafineparticles, making them especially effective against wildfire smoke. Schools canpurchase them for long-term resilience or rent them during peak smoke events tobridge short-term needs.

3. Air Quality Monitoring Together withPreparedness‍

Install low-cost PM₂.₅ sensors in multiple school spaces to understand indoor air quality trends and evaluate the effectiveness of intervention.

Use these readings to guide decisions—like limiting activities or     modifying school schedules—rather than relying solely on outdoor air quality readings.

Wrap-Up

As wildfire seasons deepen, clean air must become a cornerstone of safe schooling in BC. Relying solely on MERV 13 filters or HEPA purifiers is insufficient. Instead, a layered strategy—including HVAC optimization, air-quality monitoring, and effective purifiers like the Intellipure air purifiers—can provide the protection students and staff need.

By combining science-backed filtration methods, smart planning, and community action, schools can provide spaces where learning continues uninterrupted—without compromising health or safety.