Particulate Matter: What Is It and What are the Risks?

Key Points:

• Particulate matter is everywhere; a plethora of particles surrounds each of us

• Vaping is a source of harmful particles

• Particulate matter is associated with health risks

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What is Particulate Matter?

Particulate matter is a term that refers collectively to various particles found in the air, including dust, dirt, soot, smoke, and liquid droplets. Particles are introduced within the atmosphere by natural and human activities, including e-cigarettes and vaping.

Particles vary in size, with some being large enough to be seen with the naked eye. Particles are commonly measured in microns, a unit of measure used to describe tiny items. Particulate matter is often categorized into three main sizes: coarse (10 microns); fine (2.5 microns); and ultra-fine (0.1 micron). For perspective, the average diameter of a single human hair is about 70 microns, and fine beach sand is 90 microns. Ultra-fine particles are about one-thousandth the thickness of a human hair.

Particulate Matter and Health Implications

Researchers have examined the effects of particulate matter on human airways.

The smaller the particle size, the more deeply it penetrates the lungs and stays there longer. Ultra-fine particles can also pass into the bloodstream or disperse to other organs. However, particulate matter of all sizes has the potential to increase the likelihood of the following health issues:

• Increased hospital admissions and emergency room visits

• Respiratory symptoms such as shortness of breath, coughing and wheezing and decreased lung function

• Chest discomfort and pain

• Exacerbation of chronic respiratory (such as asthma) and cardiovascular diseases

• Headaches, fatigue, irritation of nose and eyes

Particulate Matter Health Effects

The aerosolized liquid (e-liquid) produced by vape pens has particle sizes that typically range from 0.1 micron to 10 microns. But, during vaping, particles can increase by 10 to 100 times the Environmental Protection Agency National Ambient Air Quality Standards (NAAQS).

Individuals who vape may be exposed to harmful chemicals and levels of particulate matter, according to a recent study. Researchers found an abundance of propylene glycol and glycerol or vegetable glycerin in vape. These solvents are most often used to dissolve either nicotine or marijuana-derived compounds, allowing these ingredients to be inhaled. In addition, researchers found that added flavors corresponded to an increase in particle number in e-vapors. Thermal decomposition and reactions of the refill liquid components lead to the formation of new particles.

Another study investigated e-cigarette particle emissions and vaping particle size by observing vaping sessions of 23 participants and using these findings to simulate human vaping with a smoking machine. The researchers then collected the aerosol and measured particle size. They found higher e-cigarette device power settings and vegetable glycerin-based e-liquids produced larger particles than lower settings and propylene glycol-based liquids. Puff volume also impacted vapor particle size, with longer puff durations or slower air flow yielding significantly larger particles.

The Bottom Line

Decreasing exposure to particulate matter when possible is ideal. One key step is to refrain from using e-cigarettes (or cigarettes and cigars) and quit vaping. This is especially crucial for adolescents as the full spectrum of potential health problems to arise is still being determined.

By Linda Antinoro

Reviewed by Cindy Bistany, DHSc

References:

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   https://doi.org/10.1016/j.envint.2014.10.005
   

2. Leikauf et al. Experimental & Molecular Medicine (2020) 52:329- 337

   https://www.nature.com/articles/s12276-020-0394-0/
   

3. Dada O, Castillo K, Hogan M, Chalbot MG, Kavouras IG. Evidence for the coupling of refill liquids content and new particle formation in electronic cigarette vapors. Sci Rep. 2022 Nov 3;12(1):18571. doi: 10.1038/s41598-022-21798-w. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9633786/
   

4. Son Y, Mainelis G, Delnevo C, et al. Investigating E-Cigarette Particle Emissions and Human Airway Depositions under Various E-Cigarette-Use Conditions. Chemical Research in Toxicology. 2020 Feb; 33(2):343-352 https://europepmc.org/article/MED/31804072