Wildfire Smoke & Indoor Air Quality: How to Prepare, Treat, and Clean Your Building

Wildfire season is no longer a regional concern. Smoke from large wildfires can travel hundreds or even thousands of miles, impacting indoor environments far from the fire itself. Even well-maintained buildings can experience elevated levels of fine particulate matter (PM2.5), odors, and airborne contaminants when outdoor air quality deteriorates.

For facility managers, building owners, and operations teams, protecting occupants requires a proactive strategy. The good news is that with proper planning, treatment, and cleaning procedures, your building can remain a safer, healthier refuge during wildfire smoke events.

Why Wildfire Smoke Matters Indoors

Many people assume that closing doors and windows is enough to keep smoke outside. In reality, wildfire smoke consists of microscopic particles that can infiltrate buildings through ventilation systems, building envelope leaks, and routine occupant traffic.

These fine particles can contribute to:

• Eye, nose, and throat irritation

• Reduced comfort and productivity

• Respiratory issues for sensitive populations

• Increased strain on HVAC systems

• Lingering odors and surface contamination

A comprehensive IAQ strategy should address smoke before it enters the building, remove contaminants that do get inside, and restore indoor environments after smoke events have passed.

Step 1: Plan Your Building for Wildfire Season

The best time to address wildfire smoke is before the smoke arrives.

Evaluate Your HVAC Filtration

Your HVAC system serves as the first line of defense against airborne contaminants.

Consider:

• Reviewing current filter efficiency ratings

• Upgrading to MERV 13 or higher filters when equipment allows

• Confirming fan and system capacity after filter upgrades

• Establishing a replacement schedule for smoke events

Higher-efficiency filtration captures a greater percentage of fine particulate matter commonly found in wildfire smoke.

Review Ventilation Strategies

Fresh outdoor air is typically essential for healthy indoor environments. However, during wildfire events, outdoor air may introduce significant contamination.

Building operators should:

• Develop a smoke-event operating plan

• Understand when outside air may need to be reduced temporarily

• Verify economizer controls are functioning properly

• Monitor building pressurization to prevent unwanted infiltration

Balancing ventilation and filtration becomes critical during periods of poor outdoor air quality.

Inspect Building Envelope Integrity

Smoke often enters through overlooked pathways.

Inspect for:

• Damaged door seals

• Window gaps

• Utility penetrations

• Roof openings

• Loading dock areas

Reducing leakage not only improves IAQ during smoke events but also increases overall energy efficiency.

Add Air Quality Monitoring

You cannot manage what you cannot measure.

Modern IAQ monitoring can track:

• PM2.5 levels

• Carbon dioxide

• Relative humidity

• Temperature

• Volatile organic compounds (VOCs)

Real-time monitoring allows facility teams to respond quickly when conditions change.

Step 2: Treat Indoor Air During a Smoke Event

Once smoke impacts your area, the focus shifts to protecting occupants and controlling contamination.

Increase Filtration Hours

Running HVAC systems longer—even outside normal occupancy schedules—can help remove airborne particles more effectively.

Consider:

• Extending fan operation

• Maintaining continuous airflow when practical

• Closely monitoring filter loading

Additional runtime allows filtration systems more opportunities to capture smoke particles.

Utilize Supplemental Air Cleaning

In areas with high occupancy or vulnerable populations, portable or strategically placed air cleaning devices can provide additional protection.

Effective technologies may include:

• HEPA filtration

• Properly engineered air purification systems

• Dedicated smoke-response filtration units

Not every air cleaning technology performs equally, so system selection should be based on building needs and verified performance.

Consider Advanced Air Purification Technologies

While filtration is critical, wildfire smoke presents challenges that often extend beyond particulate removal. Smoke can introduce odors, gaseous contaminants, and volatile organic compounds (VOCs) that standard HVAC filters may not fully address.

Thermal Air Quality frequently recommends solutions from GPS Air and Purafil to help facilities enhance their smoke-response strategies.

GPS Air purification systems utilize advanced ionization technologies that can help reduce airborne particulates and support cleaner indoor environments throughout occupied spaces. These systems can be integrated into existing HVAC systems to provide active air treatment beyond traditional filtration.

For facilities experiencing significant smoke odors or gaseous contamination, Purafil air filtration and chemical media solutions are designed to target molecular pollutants and odor-causing compounds that particulate filters alone may not capture effectively.

When combined with high-efficiency filtration, these technologies can provide a layered approach to improving indoor air quality during wildfire events.

Maintain Healthy Humidity Levels

Relative humidity influences occupant comfort and airborne particle behavior.

Aim to maintain indoor humidity within recommended comfort ranges while avoiding excessive moisture that could contribute to other IAQ concerns.

Monitor Occupant Concerns

Occupants often notice air quality issues before sensors trigger alarms.

Watch for reports of:

• Smoke odors

• Respiratory irritation

• Visibility haze

• Comfort complaints

Combining building data with occupant feedback creates a more complete picture of indoor conditions.

Step 3: Clean and Recover After the Smoke Clears

After outdoor air quality improves, many facilities overlook the final—and often most important—step.

Replace Impacted Filters

Wildfire smoke can significantly load HVAC filters.

Post-event inspections should include:

• Differential pressure checks

• Visual filter inspections

• Scheduled replacement when necessary

Leaving heavily loaded filters in place can reduce system performance and airflow.

Clean HVAC Components

Smoke particles can accumulate throughout HVAC systems.

Focus on:

• Air handling units

• Coils

• Drain pans

• Return air pathways

• Diffusers and grilles

Removing accumulated contaminants helps restore performance and reduce lingering odors.

Address Settled Particles

Smoke eventually settles onto building surfaces.

Prioritize cleaning:

• Hard surfaces

• Floors

• Carpets

• Upholstery

• High-touch areas

Using HEPA-equipped vacuum systems can help prevent particles from becoming airborne again during cleaning.

Evaluate Air Purification System Performance

Following a prolonged smoke event, facility managers should also inspect and evaluate any supplemental air quality systems that operated during the event.

This may include:

• Reviewing GPS Air system operation and maintenance requirements

• Inspecting Purafil media systems for loading or replacement needs

• Verifying air quality monitoring trends

• Scheduling preventative maintenance as needed

A post-event assessment ensures all IAQ technologies remain ready for future smoke events and continue delivering optimal performance.

Verify Post-Event Air Quality

A smoke event should conclude with verification rather than assumptions.

Consider:

• Reviewing IAQ monitoring trends

• Conducting particulate testing

• Evaluating occupant feedback

• Documenting lessons learned

The data gathered today can strengthen future wildfire response plans.

The Thermal Air Quality Approach

Wildfire smoke management is more than simply changing filters when outdoor conditions worsen. Effective protection requires a complete IAQ strategy that combines preparedness, filtration, monitoring, treatment, and recovery.

At Thermal Air Quality, we help facilities develop practical solutions that improve resilience before, during, and after wildfire smoke events. Whether you're evaluating filtration upgrades, implementing IAQ monitoring, or developing a smoke-response plan, our team can help create healthier indoor environments for occupants year-round.

Ready to Strengthen Your Building's IAQ Strategy?

Contact Thermal Air Quality to assess your current filtration, air treatment, and monitoring systems before the next smoke event arrives.

Because when outdoor air quality suffers, your building should remain a place of protection—not exposure.