Particulate Matter: The Basics

“Particulate matter” is also known as “Particle Pollution” or simply “PM.” The Environmental Protection Agency (EPA) describes it as “a complex mixture of extremely small particles and liquid droplets [that are] made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.” [1] Despite particulate matter’s already-diminutive nature, the EPA breaks it down further into even smaller categories based on size:Inhalable Coarse Particles– These particles are larger than 2.5 micrometers and smaller than 10 micrometers in diameter and are often referred to as PM10. [1]

Fine Particles– These particles are 2.5 micrometers in diameter and smaller and are often referred to as PM2.5. [1]

[4] Image credit: U.S. EPA

There are, of course, particles that are larger than these two categories (such as dust or pollen), but particles that are 10 micrometers in diameter or smaller are of greater concern because they are able to pass more easily through the membranes of the throat and nose and enter into the lungs and possibly the bloodstream, which can cause serious damage to the pulmonary and respiratory system. This is especially true of PM2.5, which the EPA says is of “particular concern” because of its small size and ability to travel far into the lungs. They also state that “Research has […] confirmed the links between exposure to PM2.5 and increases in respiratory health problems, hospitalizations and premature death.” [4]

How Does Course and Fine Particulate Matter Affect Your Health?

As mentioned previously, inhalable particles and especially fine particulate (PM2.5) can more easily pass through the nose and throat and enter far into the lungs, as opposed to larger-in-diameter particles. And although there doesn’t seem to be definitive proof to the theory that fine particles are more harmful than coarse particles, the EPA explains that fine particles have “the greatest demonstrated impact on human health.” [4] They cite the following possible health effects due to inhalation:

– increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty breathing, for example;
– decreased lung function;
– aggravated asthma;
– development of chronic bronchitis;
– irregular heartbeat;
– nonfatal heart attacks; and
– some cancers
– premature death in people with heart or lung disease. [3] [4]

How Does Particulate Affect You in the Workplace?

Particulate is found almost everywhere and is produced by a variety of sources: natural, man-made, and the result of chemical reactions in the atmosphere. Regulations like the Clean Air Interstate Rule, Clean Air Visibility Rule, Acid Rain Program, and Nox SIP Call (to reduce regional transport of ozone pollution) continue to decrease outdoor ambient particulate air pollution, however; further precautions may need to be taken to reduce exposure to indoor particulate matter.

You can find much of the same particulate indoors as you do outdoors, in fact; a lot of outdoor particulate makes it way inside (i.e. pollen, possibly tobacco smoke). There are also numerous work environments that expose employees to hazardous inhalable particles that are produced indoors for work purposes. In many of these cases, workers are in fairly close proximity to the source.

A few examples are Lead Dust (i.e. construction), Chromium, Metal Particulates (i.e. welding), Grinding Aluminum/Stainless, and Powders (i.e. pharmaceutical).

There are several means of removing particulate from the work area to reduce exposure. One option is to utilize a filter-based source capture air purification device.

Why High-Efficiency Filtration is Important

When you choose to use an Air Purification unit with a filtration system for particulate capture and absorption, it is incredibly important to make sure that you’re using a high-efficiency filter, like a HEPA filter (High Efficiency Particulate Air). As mentioned previously, the most dangerous particles to inhale are 10 microns in diameter and smaller (and especially 2.5 microns and smaller), which shows the importance of not only checking the total filter efficiency percentage but also what size particulate it is capable of absorbing.

Sentry Air HEPA filters are 99.97% efficient on particles 0.3 microns and larger. Our ULPA filters are 99.9995% efficient on particles 0.12 microns and larger.

If you have any questions about Sentry Air’s filter efficiency, please give us a call at 800.799.4609 or email us at

Sentry Air Systems, Inc. provides this information as a customer service, but cannot be responsible for its accuracy or completeness. It is recommended that competent legal authorities as well as safety and hygiene professionals be consulted regarding the inhalation of particulate matter.


[1] Environmental Protection Agency- “Particulate Matter”,

[2] Environmental Protection Agency- “Particulate Matter: Basic Information”,

[3] Environmental Protection Agency- “Particulate Matter: Health and Environment”,

[4] Environmental Protection Agency- “Particle Matter (PM) Research”,