Breathe Naturally - October 30, 2023

Choosing the Best Air Purifier Filters for Smoke Removal


Key Takeaways:

  • Smoke particles from sources like wildfires, cigarettes, and cooking are tiny and easily inhaled deep into lungs. Using an air purifier with the right filter is key to removing them.
  • For smoke removal, HEPA filters are recommended as the gold standard for trapping fine particles, filtering out 99.97% of particles 0.3 microns in size.
  • Activated carbon filters adsorb the gases, fumes, and odors produced by smoke. Pairing HEPA and carbon filters provides comprehensive smoke filtration.
  • Consider the CADR (clean air delivery rate) and recommended room size when selecting an air purifier filter to ensure it can handle the amount of smoke-filled air that needs cleaning.
  • Ionizing filters and ozone generators are not effective solutions on their own for removing smoke and can produce harmful byproducts. Avoid these types of filters.
  • Pre-filters extend the lifespan of HEPA and carbon filters. But be sure to change pre-filters regularly as they capture large smoke particles.
  • Following the replacement schedule for filters is important, as their trapping capabilities wear down over time while exposed to smoke.

The Dangers of Indoor Smoke Exposure

From wildfire smoke seeping into homes to cigarette smoke lingering long after, indoor air can easily become contaminated with hazardous smoke particles. The tiny size of smoke means it can be readily inhaled deep into lungs. According to the EPA, sustained smoke exposure contributes to 1 in 5 deaths worldwide (1).

Smoke released indoors is especially concerning, as the closed environment allows pollutants to accumulate rapidly to dangerous levels. Sources of indoor smoke can include everything from burnt cooking to recreational marijuana to cigarettes and fireplaces. Extended exposure without proper ventilation or filtration puts the health of building occupants at risk.


Using an air purifier equipped with the most effective filter technology is one important way to actively decrease smoke particles circulating indoors. But not all filters are capable of capturing the tiny particulates smoke contains.

Smoke Filter Options and Limitations

There are a wide variety of air purifier filters in today's market that use different techniques for particle removal. Important considerations when selecting a filter to clean smoke from indoor air include:

Particle Removal Efficiency - The most critical metric, this measures the percentage of particles removed at specific sizes. For fine smoke, True HEPA rated filters are recommended as they catch 99.97% of 0.3-micron particles.

Absorption Capacity - Smoke gases and odors also need to be filtered out. Activated carbon adsorption is ideal for removing fumes along with HEPA filtration.

Clean Air Delivery Rate (CADR) - CADR measures volume of filtered air delivered per minute. Match this to the total square footage the purifier will cover to ensure enough capacity for the space being cleaned.

Limitations - Ionizing filters and ozone generators are often ineffective for smoke and can produce harmful byproducts. These limitations make them unsuitable options.


Why HEPA Filters are Essential for Smoke

HEPA (High Efficiency Particulate Air) filters are considered the gold standard for trapping fine particles like smoke. To qualify as True HEPA, filters must remove 99.97% of particles sized at 0.3 microns (2). Smoke particles and emissions fall within this range, making HEPA filtration extremely effective.

The key is the dense woven glass fibers in HEPA filters that prohibit particles passing through. This creates significant airflow resistance however, so HEPA filters require more powerful fans and energy usage in air purifiers. But when it comes to health hazards like smoke, HEPA filtration provides life-saving protection from dangerous particulates other filters miss.

When evaluating HEPA filters, look at the clean air delivery rate (CADR) and recommended room size. Match or exceed the size for your space and an adequate CADR for total area in order to provide sufficient cleansing of smoke-filled air. Replacing HEPA filters at least every 12 months maintains high performance as fibers wear down over time.


Activated Carbon Capture for Gases and Odors

While HEPA filtration is essential for capturing particulates, smoke gases and odors will pass right through. That's where activated carbon filters come in. The porous structure of activated carbon traps smoke gases through adsorption to its surface rather than filtering (3).

The combination of HEPA and activated carbon in an air purifier provides comprehensive protection by filtering both smoke particulates as well as hazardous fumes and odors. Activated carbon does saturate over time as pores fill, so replacement is needed to maintain gas absorption capabilities.

When comparing the amount of activated carbon, heavier weights indicate greater adsorption capacity. Pellet forms also allow more airflow than powered carbon. Pairing a high-quality HEPA filter with the largest amount of activated carbon offers the best solution for smoke-filled air.

Ionizers and Ozone Generators: Avoid These

Some air cleaning devices rely on technologies like ionizers or ozone generators. But these are not recommended, especially for smoke removal. Here's why:

  • Ionizers - Electrostatically charge particles to attract to surfaces. But do not properly filter most smoke particles. Also produce ozone as byproduct.
  • Ozone Generators - Designed to produce ozone to react with pollutants. But ozone does not effectively remove most smoke particles or gases. Also very harmful for breathing.

The small, ionized particles and ozone created by these devices can worsen indoor air quality rather than clean it when smoke is present. Stick with certified HEPA and activated carbon filters as the proven, safest technology.

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Extending Filter Life with Pre-Filters

Pre-filters can help extend the working life of both main HEPA and carbon filters in an air purifier by trapping larger particles first. This keeps the smaller pores in HEPA and carbon from getting overloaded as quickly.

For smoke, pre-filters capture initial layers of soot, ash, and debris. But they do fill up rapidly when dealing with smoke pollution. Be sure to replace pre-filters per the manufacturer's recommendations to prevent impact on performance of the downstream main filters.

Some pre-filters feature an antimicrobial treatment as well to inhibit bacteria growth from captured smoke particulates. This provides an added level of protection against germs the smoke carries in.

Maintaining Performance with Replacement

Any air purifier filter loses efficiency over time as pores clog and fibers wear down. But when dealing with hazardous particulate pollution from sources like smoke, maintaining peak performance is critical for health.

Follow the filter replacement schedule in an air purifier’s manual. Most HEPA filters need annual replacement, while 1-3 months is often recommended for activated carbon filters in smoke-heavy environments. Signing up for replacement reminders from the manufacturer ensures filters get swapped out on time.

Don't let air filters overstay their welcome when the air quality stakes are high with smoke contaminants. Employing True HEPA and activated carbon models sized appropriately for space provides the greatest protection indoor environments can have from the dangers of smoke.


1. U.S. Environmental Protection Agency. Wildfires and Indoor Air Quality (IAQ).

2. U.S. Environmental Protection Agency. What is a HEPA filter?

 3. U.S. Environmental Protection Agency. Adsorbent Air Cleaners and Air Purifiers.