MODULE 2 Regulatory Standards for Particulate Matter

Particulate Matter (PM)

Sources of particulate matter include motor vehicle tires and brakes, wood burning stoves, fireplaces, construction site dust, landfill operations, agriculture operations, brush burning, waste burning, wildfires, industrial sources and windblown dust from open land. In addition to its potential harmful human health effects, PM is often responsible for much of the haze described as smog. Airborne PM is a problem in several of our cities, rural areas, national parks and forests.

How Particulate Matter Enters Our Body

PM10 (big) particles can stay in the air for minutes or hours while PM2.5 (small) particles can stay in the air for days or weeks. Because of these residence times, PM10 particles can travel as little as a hundred yards or as much as 30 miles while PM2.5 particles go even farther; many hundreds of miles.

As mentioned in Module 1, PM can have grave health effects, especially PM2.5 as the particles are so small, they can pass through the alveoli and directly into your blood stream. The air and the particles travel into your respiratory system (your lungs and airway). Along the way the particles can stick to the sides of the airway or travel deeper into the lungs. The farther they go, the worse the effect.

Your lungs produce mucous to trap the particles, and tiny hairs wiggle to move the mucous and particles out of the lung. If the particle is small and it gets very far into the lungs, special cells in the lung trap the particles and this can result in lung disease, emphysema, lung cancer.

Both PM10 (big) and PM2.5 (small) particles can cause health problems; specifically respiratory health (that's the lungs and airway). Because the PM2.5 travels deeper into the lungs AND because the PM2.5 is made up of things that are more toxic (like heavy metals and cancer causing organic compounds), PM2.5 can have worse health effects than the bigger PM10.