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Everything You Need to Know about Particulate Matter

What Particulate Matter Is, Why It’s Sometimes Hazardous, and How to Reduce Its Adverse Effects


Indoor air quality has become increasingly important for many businesses and private residences. Given an increased awareness of how the air we breathe affects our overall health, here’s what you need to know about one important element of indoor air quality: particulate matter.


What Is Particulate Matter?


Particulate matter is the sum total of organic and inorganic particles suspended in an environment. If you’re doing research on this topic, be aware that particulate matter can be called several different names, including PM, particle pollution, and suspended particulate matter.


Some particulate matter, such as certain kinds of soot, dirt, or smoke, can be seen with the naked eye. Others are microscopic and cannot be perceived without equipment.


Particulate matter is broken into three categories:

CoArse particulate matter

2.5 to 10 microns

Fine particulate matter

0.1 to 2.5 microns

Ultrafine particulate matter

smaller than 0.1 microns


PM 2.5 Size




Not sure how large a micron is?

For context, a single human hair is typically anywhere from 50 to 70 microns.









Common Examples of Particulate Matter


Particulate matter is around us all the time. It’s in our indoor air, and it’s in the air we breathe outside. It includes all the following:

  • Bacteria

  • Combustion activities

  • Dust

  • Mold spores

  • Pollen

  • Power plant emissions

  • Smoke

  • Vehicle exhaust


Particulate matter can either be directly emitted from multiple sources or formed through atmospheric reactions. For example, wind might disperse dust or pollen. This is the direct form of emission known as primary particles. Particles can also enter suspension when a vehicle, power plant, industrial building, or the like emits material that then forms particulate matter with gaseous pollutants. These are known as secondary particles.


With Particulate Matter, Size Is Everything


Some particulate matter is not harmful at all; other types can be extremely hazardous. Determining this has a lot to do with the size of the individual particles. The smaller the particle, the more likely it is to be associated with health concerns.


Particles that are larger than 10 microns are not usually of significant concern. These particles can, however, still irritate eyes, noses, throats, and airways.


Smaller particles, particularly those of 2.5 microns or less, present the most significant health concerns. These particles don’t just irritate you on a surface level. They are small enough to lodge into your lungs or even to enter your bloodstream.

5–10 microns

Enters nose and pharynx

3–5 microns

Enters trachea

2–3 microns

Enters bronchia

1–2 microns

Enters bronchioles

0.1–1 microns

Enters alveoli 



Health Effects in Humans


The effects of particulate matter exposure are primarily seen in the heart, lungs, or both. These effects can range from decreased lung function and worsening asthma to irregular heartbeat and premature death.



Those most at risk are people with preexisting heart or lung conditions. This includes asthma, COPD, and many others. The elderly and very young children are also both more susceptible to the negative effects of particulate matter.


In addition to the size of the individual particles, exposure time also plays a big role in the net health effect. Long-term exposure is more likely to cause harm like decreased lung function or chronic bronchitis. Short-term exposure is linked to the triggering of asthma attacks, acute bronchitis, and heart arrhythmias.



It is important to note there is no definitive or reported link between particulate matter exposure and negative health effects in otherwise healthy adults and healthy children. There might be some minor irritation, but this is usually temporary and not critical.


It’s also important to remember that physical activity can exacerbate the effects of particular matter because exercising causes you to breathe deeper and faster. If you know air quality is low—from forest fire smoke or any other source—make sure to limit outdoor activity.


Health Effects in Nature




Particulate matter can also be detrimental to the environment itself. Increased particulate pollution contributes to all the following:

  • Haze and reduced visibility

  • Increased acidity in bodies of water

  • Depletion of nutrients in soil

  • Increased effects of acid rain


Particulate Matter and Viruses


Another concern related to particulate matter is its role in virus transmission. While this is obviously a concern during a global pandemic, viruses are always present, making this relationship relevant at any point.

Blue Virus


Several studies indicate particulate matter can serve as a carrier for airborne pathogens. This means greater levels of particulate matter make virus transmission more likely and frequent.


In the specific case of SARS-CoV-2, a correlation has been made between high levels of particulate matter and both transmission rate and case severity.





Who Can Benefit from Particulate Matter Mitigation?


Anyone can benefit from reducing the amount of particulate matter in an indoor space. This includes any of the following:

  • Homeowners who simply want cleaner air

  • Anyone who has or is living with someone who has a condition that makes particulate matter more hazardous (elderly, young children, anyone with an underlying heart or lung condition)

  • Business owners who want to offer cleaner air in their commercial spaces in order to boost patron confidence and revenue potential


How to Reduce Particulate Matter


Whether you’re a private homeowner or you’re in charge of a commercial space, it is possible to reduce the amount of indoor particulate pollution. The EPA recommends several best practices for reducing particulate matter.

  • Vent any fuel-fired combustion appliance (stove, heater, furnace) outdoors

  • When cooking, utilize exhaust fans that are vented outdoors

  • Ensure all woodstove doors fit properly and tightly

  • Have a professional annually inspect your central heating system, including furnace, flue, and chimney

  • Change out any filters on your heating and cooling system or air-cleaning system as directed by the manufacturer


HVAC filter




You can also upgrade your HVAC filters to MERV-13. These have been shown to remove greater than 85 percent of particles between 1 and 3 microns.




R6.0 View 2



Another ASHRAE-condoned solution is to “[c]ombine filters and air cleaners to achieve MERV 13-equivalent or better levels of performance for air cleaning.”

One way to do this is by pairing a more standard MERV-8 filter with an HVAC-installed air-cleaning system, such as Needlepoint Bipolar Ionization.




Why would you want to do that instead of simply using the MERV-13 filter? It has to do with cost and energy efficiency.


  • First off, MERV-13 filters are more expensive than MERV-8 filters, so there’s this initial cost to consider.

  • Second, the weave on a MERV-13 filter is tighter than a MERV-8 filter in order to capture smaller particles. This also affects airflow. It’s harder for air to push through those filters, which means you’re putting more strain on your overall HVAC system. It also requires more energy consumption to operate.


Testing done at a global hospitality chain combined Needlepoint Bipolar Ionization technology with a MERV-8 filter and compared this to a MERV-13 filter alone. The filter and air-cleaning technology combination operated at 70 percent efficiency, which equaled or outperformed the standalone MERV-13 filter. It did this without the additional energy requirements or extra strain on the HVAC system.

Graph of Particulate Reduction Results


Have Questions about Particulate Matter Mitigation?

Are you a homeowner who’s interested in reducing the amount of particulate matter in your private residence? A business owner looking to improve the air quality in your commercial space?

Reach out today. We’re always happy to answer your questions!