Understanding Particulate Matter & Its Health Risks

Understanding Particulate Matter & Its Health Risks

The quality of the air we breathe is fundamental to our individual health and the health of the planet. As such, studying and regulating air pollution has been a priority across the globe for decades now; the United Kingdom enacted sweeping air pollution regulations in 1956, and the U.S. adopted the Clean Air Act in 1970.1,2

Air pollution is a concern both outdoors and indoors: the World Health organization (WHO) estimates that, across the globe, roughly 4.2 million people die prematurely each year due to indoor air pollution.3 Furthermore, half of all illnesses can be caused or aggravated by poor indoor air quality.4 This makes sense, given that we spend the large majority of our lives indoors (the average American spends more than 90% of their time inside buildings and in their vehicles).5  

According to the U.S. Environmental Protection Agency (EPA), there are six main air pollutants that the agency regulates: carbon monoxide, nitrogen oxides, ground-level ozone, sulfur oxides, lead and particulate matter.6

Spotlight on Particulate Matter

Particulate matter (PM)—consisting of tiny liquid droplets or solid particles like smoke, dust and soot—can come from a variety of sources, including:7

  • Coal fires
  •  Construction sites
  • Emissions from power plants and industrial facilities
  • Gases from power plants that turn into particles
  • Smoke from wildfires
  • Vehicle emissions
  • Wood stove use

Different sizes of particles can cause different problems for human health. Larger particles that are around 10 micrometers in diameter (PM10) can sometimes be seen with the naked eye. They can irritate the eyes, nose and throat and cause trouble breathing. Smaller particles that are 2.5 micrometers and smaller (PM2.5) can go deep into the lungs and even get into your blood. Inhaling PM2.5 particles can worsen coronary and respiratory disease symptoms, such as asthma and bronchitis, lead to lung cancer and contribute to babies born with low birth weight, among other health issues.8,9

Both PM10 and PM2.5 particles can be inhaled. For perspective, PM2.5 particles can be 30 times smaller than a single human hair.

While legislation such as the Clean Air Act has improved air quality for some parts of the world, air quality is worsening in others. A study published in 2020 in Climate and Atmospheric Science found that more than 55% of the world’s population was exposed to increased levels of particulate matter, specifically PM2.5, between 2010 and 2016. During that time frame, North America and Europe saw decreased average population-weighted concentrations of particulate matter while Central and Southern Asia saw increased concentrations.10

Detecting Particulate Matter in the Air We Breathe

Solving the particulate matter challenge is difficult because PM is made up of many different substances from a wide range of sources.11 However, modern HVAC systems for homes and commercial buildings, indoor air quality monitors and cabin air purifiers for airplanes, cars and other vehicles have adopted technologies that make it quicker and easier to detect how much PM in the air.

One such technology is a particulate matter sensor. These sensors use either laser technology or light-emitting diode (LED) to detect and count particles through light scattering. Light reflects off the particles and is recorded on a light detector. It is then analyzed and converted into an electrical signal to calculate particle concentration, as measured in micrograms.

When built into equipment like an HVAC system, these sensors will help “tell” the equipment when to trigger fresh air circulation into an indoor space to aid in improving the air quality.

What Makes a Good PM Sensor?

It is critically important for PM sensors to respond quickly and be highly accurate; knowing the exact concentration of particulate matter in the air in real-time with very little margin of error is vital to the safety of indoor air environments. These sensors must also be durable to withstand the conditions within an HVAC system. They should be efficient as well, consuming as little power as possible to extend the life of the equipment they are housed in.

Honeywell’s latest PM sensor, the Intelligent Particulate Matter Sensor (IPM Series), can measure PM1.0, PM2.5, PM4.0 and PM10-sized particles. Its small size and metal casing make it durable and easy to integrate for a variety of different needs. It has three digital output options and self-calibration capabilities, which enhances drift mitigation, helps improve uptime and limits the need for frequent maintenance.

To learn more about how Honeywell’s sensing technologies are making a difference across industries, visit our website.


·         1 - www.smithsonianmag.com/science-nature/supreme-court-clean-air-act-environmental-protection-agency 21017286/#:~:text=The%20United%20Kingdom%20adopted%20broad,passed%20the%20Clean%20Air%20Act.

·         2 - www.epa.gov/clean-air-act-overview/evolution-clean-air-act

·         3 - www.weforum.org/agenda/2022/07/what-causes-indoor-air-pollution-sources-how-to-reduce    

·         4 - www.indoorairhygiene.org/pm2-5-explained

·         5 - www.epa.gov/report-environment/indoor-air-quality#:~:text=Americans%2C%20on%20average%2C%20spend%20approximately,higher%20than%20typical%20outdoor%20concentrations.

·         6 - www.cdc.gov/air/pollutants.htm

·         7 - www.cdc.gov/air/particulate_matter.html

·         8 - www.cdc.gov/air/particulate_matter.html

·         9 - www.epa.gov/indoor-air-quality-iaq/indoor-particulate-matter; www.epa.gov/pm-pollution/particulate-matter-pm-basics

·         10 - www.nature.com/articles/s41612-020-0124-2

·         11 - www.nrdc.org/stories/air-quality-worsening-half-worlds-people