Particulate Matter: What is it and what does it do

Particulate Matter (PM) is a mix of solid and liquid pollutants that can be separated into the two categories depending on their size. PM2.5 are fine particles that are 2.5 micrometers in diameter; PM10 are coarse particles that are between 2.5 and 10 micrometers. Additionally, there is a category known as ultrafine particles, which are smaller than 0.1 micrometers.

Source: California Environmental Protection Agency (
Source: California Environmental Protection Agency (

PM can originate from various sources, which then determine the composition of the PM and the effects it could cause. Typically, PM is made up of nitric acids, sulfuric acids, other organic chemicals, metals, and soil/dust particles. PM10 primarily are dust and soot, which can be from vehicles on roadways and industrial areas. PM2.5 are generally from forest fire smoke and industrial combustion sources.

PM can be in the form of smoke, soot, dust, salt, acids, and metals. Additionally, PM can be from gaseous nitrogen oxides and sulfur oxides when they are released into the atmosphere (typically from burning fossil fuels) and undergo chemical reactions with the ozone to become PM. This reaction is called oxidation. Further reaction with water vapor can lead to acid rain formation.

Because they are so small, PM can be easily breathed in by people, entering the respiratory system and wreak havoc on their cardiovascular system. PM10 is large enough to get caught in mucus or cilia of the nose and throat, which will lead to coughing and expelling the particulate matter out.

PM2.5 are small enough to enter the lungs, as deep as the bronchioles (passageway from nose or mouth to the air sacs) and alveoli (air sac surrounded by artery and veins, which is where the blood cells exchange carbon dioxide for oxygen). Because PM2.5 can penetrate deeper into the lungs, the severity of the health effects increases.

Ultrafine PM can integrate into the bloodstream through the alveoli.  This causes PM to spread throughout the body into organs such as the heart and brain. PM is made up of toxic pollutants. Accumulation of PM in the body can create chronic respiratory problems. For people with heart or lung diseases and exposure to PM have a higher risk of premature death and heart attacks. Overall any prolong exposure to any PM is toxic and leads to health problems. When exposed to PM, people with existing heart and lung diseases, young children, and the elderly are at high risk for health complications.

Since 1995, the National Center of Environmental Research (NCER) has been studying PM to further understand its health impacts on people and the environment. Their discoveries will help set up the PM National Ambient Air Quality Standards. Research will allow both the government and public to understand what PM is and what to do about it.

Click on the image to follow an animation on how PM and other airborne toxins affect the body.
Click on the image to follow an animation on how PM and other airborne toxins affect the body. (Source:

Information obtained from Environmental Protection Agency (EPA) and Clean Heat Asbruton

Particulate Matter Pollution

John Irvine

Particulate Matter

Professor Pearson

November 22, 2013


Imagine a middle-aged person who has plenty of living left to do, and many dreams still left to fulfill with the years that s/he has left.  Now steal from that person the last ten years of her/his life, along with all of those aspirations that s/he longed to achieve.  This is the unscrupulous wrath of air pollution, and it can take up to those ten years from 200,000 people each year in the United States, according to the presentation of Dr. Nicky Sheats, Esq., Director, Center for the Urban Environment of the John S. Watson Institute for Public Policy of Thomas Edison State College.

Reducing air pollution would obviously reduce those numbers, and that much is apparent, but what is not often so readily apparent is that there are different forms of air pollution that cause those deaths.

The topic of pollution brings to mind debates about greenhouse gases and global warming, but even more directly lethal to humans is particulate matter pollution.

“It sounds like something that’s not a gas, but that’s an actual particle, and I guess it’s stuff that can get into people’s lungs” speculated Dr. Nina Peel of TCNJ’s biology department.

Jamie Grasing, a junior at Loyola University Maryland, had a similar surmise: “ I imagine little particles that are lighter than air that are able to float in the atmosphere.”

Particulate matter is just what it sounds like: particles of matter that come mostly from diesel exhaust and industrial smokestacks.  The danger is that the particles are so tiny that they can bypass the security of the lungs and enter the bloodstream.

Although particulate matter pollution takes 200,000 lives each year, and although there are continual struggles between regulators, environmentalists and industry representatives about what should constitute and acceptable pollution levels, few can say what particulate matter pollution is.

“Maybe because we’re not living in this urban area.  Here we are so suburban so we always assume that the air is clean.  The type of pollution doesn’t come up.  If you are in New York City, then you worry about it.  I’ve never really thought about different types of pollution,” said a TCNJ health and exercise science professor.

Not many people realize that multiple types of pollution exist, and that they affect humans in different ways.  Surely, this is connected to the health and exercise science professor’s idea that residents of suburban areas have a hopeful sense of security in cleaner air.

“Maybe asbestos would be considered particulate matter, and that is going to have a somewhat different effect on people’s health in that it’s going to have its effect probably limited to those cells that it actually encounters,” reasoned Dr. Peel.

Envision the exhaust that trucks spew: it is quite visible to the naked eye, not something that could be said of greenhouse gases.  The visible exhaust from trucks is the particulate matter pollution, and it’s visible because millions of these solid and liquid particles clump together when they’re emitted.

The danger with particulate matter pollution is that the toxicity of the pollutants, if small enough, can wreak havoc on more than just the cells which they initially contact.  Particles that are less than 2.5 microns in diameter can easily enter the blood and circulate throughout the body.  For comparison, the diameter of a human hair is 45 microns.

“I find it quite interesting, the particulate matter pollution, because I never thought about gas pollution versus little solids pollution.  I just never would have thought that a truck spewing visible emissions is its own type of pollution,” said Matthew Schirm, a sophomore at Seton Hall University.

The danger of particulate matter pollution is also much more severe than many realize.  These particles are actually stealing time from people’s lives.

“Deaths can occur on the very day that particle levels are high, or within one to two months afterward. Particle pollution does not just make people die a few days earlier than they might otherwise—these are deaths that would not have occurred if the air were cleaner,” according to the American Lung Association’s website.

Although these facts offer a bleak outlook on the future quality of air, there has been inspiring evidence on the other end of the spectrum.

“Looking at air quality in 545 counties in the U.S. between 2000 and 2007, researchers found that people had approximately four months added to their life expectancy on average due to cleaner air,” said the American Lung Association’s website.

Two-hundred thousand deaths per year is surely no small matter, so how is it that the public knowledge of the source of those deaths is particle-sized?