Can HVAC Filtration Help Reduce Airborne Microplastics?

Microplastics are becoming part of the indoor air quality conversation. While many people think of microplastics as something found in water or food, research is also looking at how small plastic particles and fibers may move through the air inside homes, offices, schools, and other buildings. Indoor environments are increasingly recognized as an important pathway for airborne microplastic exposure, although methods and findings are still developing.


For IAQ professionals, one practical question is worth asking: Can HVAC filtration help reduce airborne microplastics?

The answer is yes, filtration may help reduce airborne particles, including some microplastics. But it is important to understand what filtration can do, what it cannot do, and why proper maintenance matters.


What Are Airborne Microplastics?

Microplastics are very small plastic particles, generally smaller than 5 millimeters. Indoors, they may come from synthetic textiles, carpets, upholstery, furniture, packaging, electronics, plastic-based materials, and settled dust.

Some microplastics can become airborne through normal building activity. Walking, cleaning, opening and closing doors, using HVAC systems, or disturbing soft materials can move particles from surfaces into the air.

Because indoor spaces are enclosed, these particles may settle, recirculate, or build up in dust if they are not managed through source control, cleaning, ventilation, and filtration.

How HVAC Filtration Fits Into the IAQ Picture

HVAC filters are designed to capture particles from air moving through the system. Depending on the filter rating, system design, air flow, installation, and maintenance, filtration can help reduce the amount of particulate matter circulating indoors.

This matters because airborne microplastics are part of the broader particle conversation. They may vary in size, shape, and material. Some may be large enough to settle quickly, while smaller particles and fibers may remain suspended longer and move through indoor air.

A good HVAC filtration strategy may help capture some of these particles, especially when filtration is properly matched to the building and system.


Understanding MERV Ratings

Many HVAC filters are rated using MERV, which stands for Minimum Efficiency Reporting Value. MERV ratings help describe how well a filter captures particles within certain size ranges. ASHRAE Standard 52.2 is the commonly referenced method for evaluating filter performance by particle size range.

In general, higher MERV ratings capture smaller particles more effectively. ASHRAE has recommended MERV 13 filters where systems can accommodate them, and notes that many relevant indoor particles fall within the 1 to 5 micron size range.

However, a higher MERV filter is not always automatically better for every system. If the filter creates too much resistance, it may reduce airflow or place stress on equipment. IAQ professionals should consider system compatibility before recommending or installing a higher-efficiency filter.



What About HEPA Filtration?

HEPA filtration is another important part of the conversation. According to the U.S. Environmental Protection Agency, HEPA filters can theoretically remove at least 99.97% of airborne particles at 0.3 microns, including dust, pollen, mold, bacteria, and other particles.

Most standard residential or commercial HVAC systems are not designed to use true HEPA filters without special equipment or system modifications. However, portable air cleaners with HEPA filtration may be useful in certain rooms or areas when they are properly sized, placed, and maintained.

For microplastics, this means HEPA filtration may help reduce airborne particles in the size ranges the filter is designed to capture. But it should not be presented as a complete solution or a replacement for good building practices.


Maintenance Matters

Even a good filter cannot perform well if it is not maintained.

A practical filtration plan should include:

  • Using a filter that fits properly in the system
  • Replacing filters on the recommended schedule
  • Checking for gaps, bypass, or poor filter seating
  • Making sure the HVAC system can handle the selected filter
  • Keeping return vents and supply vents clear
  • Evaluating whether additional portable filtration is needed in high-use spaces

Filter bypass is especially important. If air can move around the filter instead of through it, particle capture is reduced. Proper installation and routine inspection are simple but important steps.


Realistic Expectations

HVAC filtration can support better indoor air quality, but it is only one part of a larger strategy.

Filtration may help reduce airborne particles, including some airborne microplastics. But it will not remove particles already settled in dust, eliminate the source of shedding materials, or address all indoor contaminants.

A stronger IAQ approach includes:

  • Source control
  • Regular dust management
  • Proper ventilation
  • Appropriate HVAC filtration
  • Portable air cleaning where needed
  • Moisture and humidity control
  • Routine inspection and maintenance

This balanced approach is especially important when discussing emerging topics like microplastics. The goal is not to create alarm. The goal is to help building owners, facility managers, and occupants understand practical ways to reduce exposure while the science continues to develop.


What IAQ Professionals Can Tell Clients

When clients ask about microplastics and filtration, a simple explanation may help:

“HVAC filtration can help reduce some airborne particles, including particles that may include microplastics, but it works best as part of a broader IAQ plan. The right filter, proper system compatibility, regular replacement, good cleaning practices, and source control all matter.”


The Bottom Line

HVAC filtration can help reduce airborne particles indoors, and it may play a role in reducing some airborne microplastics. But filtration should be presented with realistic expectations.


For IAQA members and IAQ professionals, microplastics are another reminder that indoor air quality is connected to building materials, occupant behavior, cleaning practices, ventilation, filtration, and ongoing maintenance.

IAQA and Particles Plus Expand Strategic Partnership Through New Eight-Year Extension

By Sarah Fanger • July 22, 2026
The Indoor Air Quality Association (IAQA) is pleased to announce an eight-year extension of its sponsorship agreement with Particles Plus, building on the second year of the parties’ original two-year agreement. With this extension, Particles Plus will continue as IAQA’s exclusive Diamond Sponsor, reinforcing its commitment to supporting the association’s mission, initiatives, and long-term growth. In addition to its financial support, Particles Plus will provide strategic services and advisory guidance to assist IAQA as it strengthens programs, expands industry engagement, and advances its service to members and the broader indoor air quality community. “Particles Plus has already proven to be a valued partner to IAQA, and this extension reflects both the strength of our relationship and our shared confidence in the future,” said Stanley Yeskolski, President of IAQA. “As Diamond Sponsor, their continued support, strategic services, and advice will help IAQA grow, better serve our members, and further our mission across the indoor air quality industry.” “IAQA plays an essential role in supporting professionals who work every day to improve indoor environments,” said Adam Giandomenico, CEO of Particles Plus. “We are proud to extend this partnership for eight more years and to support IAQA not only through sponsorship, but also through strategic collaboration that helps the association strengthen its programs and expand its impact.” This renewed agreement reflects a shared commitment to advancing indoor air quality knowledge, supporting practitioners, and promoting healthier indoor environments through collaboration, education, and industry leadership. The original commitment began in 2025 and now will continue through 2035. 
Wildfire Smoke and Respiratory Protection

Wildfire Smoke and Respiratory Protection: Why N95 and KN95 Respirators Work Better Than Surgical Masks

July 18, 2026
Wildfire Smoke and Respiratory Protection: Choosing the Right Mask Wildfire smoke can affect communities located far beyond the fire itself. Wind can carry smoke across cities, states, and even national borders, as is happening currently across the Great Lakes and Northeastern US due to Canadian wildfires. The result is poor to hazardous air quality both outdoors and inside buildings. One of the main concerns in wildfire smoke is PM2.5. These particles are extremely small and can travel deep into the respiratory system. Exposure may irritate the eyes, nose, throat, and lungs. It can also worsen asthma, heart disease, and other existing health conditions. When outdoor air quality becomes unhealthy, reducing exposure should be the first priority. Staying indoors, keeping windows closed, using effective air filtration, and avoiding strenuous outdoor activity can all help. When going outside is necessary, wearing the right respiratory protection is important.

Wildfire Smoke Doesn't Stop at Your Front Door

July 17, 2026
When wildfire smoke rolls in, most people think about it as an outdoor problem: hazy skies, stinging eyes, the advice to stay inside. But "inside" isn't automatically safe. Smoke particles are small enough to slip through open windows and doors, gaps around trim and outlets, HVAC intakes, and even tiny leaks in the building envelope itself. Once they're in, they don't just disappear — they settle into carpets, upholstery, and ductwork, and keep affecting air quality long after the skies clear outside. Why Indoor Air Takes the Hit Too Wildfire smoke is loaded with fine particulate matter (PM2.5) — particles so small they bypass your body's natural filters and reach deep into the lungs. Unlike larger dust or pollen, these particles move easily through the small openings that exist in almost every building, including: Open or poorly sealed windows and doors Gaps around pipes, vents, and electrical penetrations HVAC systems pulling in outdoor air Cracks in the building envelope (siding, roofline, foundation) Without preparation, indoor PM2.5 levels can climb close to outdoor levels within hours of a smoke event starting. Preparing Before Smoke Arrives The best defense is proactive, not reactive. A few key steps make a real difference: 1. Seal the gaps. Weatherstripping, door sweeps, and caulking around penetrations reduce how much smoke can infiltrate. 2. Upgrade HVAC filtration. Use the highest MERV rated filter that your system is rated for; check with your HVAC company if you aren’t certain. A MERV 13 or higher filter (where the system allows) captures significantly more fine particulate than standard filters. 3. Have a portable air cleaner ready. HEPA-based units with adequate CADR(Clean Air Delivery Rate) ratings for the room size can be a fast, effective backstop, especially in bedrooms or common living areas. 4. Set HVAC systems to recirculate. Switching off fresh-air intake during active smoke events keeps outdoor smoke from being pulled directly inside. 5. Know your air quality resources. Track local AQI before smoke hits so you can act early instead of waiting until conditions are already unhealthy. The Takeaway Wildfire season is as much an indoor air quality issue as an outdoor one. Buildings are more porous than they look, and smoke will find its way in through the paths of least resistance. Preparing ahead of time — sealing gaps, upgrading filtration, and having a response plan — is what separates a minor inconvenience from a real health risk indoors.  Want more practical guidance on protecting indoor air during wildfire season? Explore IAQA's resources and connect with certified indoor air quality professionals at iaqa.org .