Big Picture LinkParks LinkSkyrider Link
The Air We Breathe: The High Cost of Inhaling

 Diagram showing the size of PM-10 and PM-2.5 compared to a human hair

Click on a choice:

  EPA Standards: Minimizing the Risk

  People, Air & Fire: The Burning Questions

  What should we all know about fire?

  The Air We Breathe: The High Cost of Inhaling

  History, Ecology & Choices: What Everyone Should Know

  Air Quality Timeline


What is in smoke from fires?

Smoke contains microscopic particles, called particulate matter, which are smaller than 10 microns in size or about one fifth of the thickness of a human hair. Even finer particulate matter, smaller than 2.5 microns in diameter, are also present.

Air quality effects of smoke:

  • Reduced visibility
  • Huge emissions of particulate matter smaller than 2.5 microns, known as PM2.5, are pumped into the air and are responsible for the smoky haze that spreads over wide areas during a fire
  • Also, these particles can be inhaled into the tiny air sacs of our lungs and cause permanent damage

Particulate Levels Set By the EPA

  • The EPA set a PM2.5 standard of 65 micrograms per cubic meter averaged over 24 hours.
  • PM2.5 levels are measured locally by a portable particulate monitor.
  • The PM2.5 readings are then converted to the State Pollutant Standards Index (PSI) and used to give guidance on health and advised activity levels.

Federal Health Standard

Health Advisory for Ozone: Unhealthy

Stage 1 Alert: Very Unhealthy

Stage 2 Warning: Hazardous

Stage 3 Emergency

PSI 100

PSI 150 and Above

PSI 200 and Above

PSI 300 and Above

PSI 400 and Above

People sensitive to air pollution should reduce physical exertion and limit outdoor activity.

Everyone should limit vigorous outdoor activity.

Everyone should avoid vigorous outdoor activity. Sensitive people should stay indoors.

Everyone should limit any outdoor activity. Sensitive people should stay indoors.

Everyone should stay indoors with windows and doors closed and minimize physical activity.

- How can smoke from fires be managed?... 
© 2003 Delphi International. All Rights Reserved.