PM2.5 AQI

There are hundreds of sources of outdoor air pollutants. The main contributors that increase the levels of particulate matter outdoors are:

  • Vehicles
  • Power generators
  • Industrial and agricultural emissions
  • Residential heating and cooking
  • Manufacture and distribution of chemicals
  • Forest fires

 

 

Why is it called 2.5?

The 2.5 in PM2.5 refers to the size of the pollutant in micrometers. Bear with us here while it gets a bit mathematics-y! Micrometers have this symbol: µm and are equivalent to 0.001 millimeters. The smallest thing that the average human eye can perceive is about 0.1 millimeters, which is around the same width as a human hair. So in order for us to see something as incredibly small as a micrometer, we need to use powerful microscopes. Here’s a diagram from the Environmental Protection Agency to help you visualize the scale of these tiny particles.


What are the negative effects of exposure to PM2.5?

Depending on how healthy you are in general, PM2.5 will have different long and short term negative health effects. When exposed to levels of PM2.5 between to moderate – hazardous range, one may experience the following effects:

  • Shortness of breath
  • Eye, nose and throat irritation
  • Excessive coughing and wheezing
  • Diminished lung function and lung disease
  • Diminished heart function, sometimes resulting in heart attack
  • Asthma attacks
  • Death

 

AQI Catagory Range Health Level Description
Good 0-30 Good Minimal impact
Satisfactory
 
31-60 Moderate May cause minor breathing discomfort to sensitive people.
Moderately Polluted 61-90 Unhealthy for sensitive groups May cause breathing discomfort to people with lung disease such as asthma, and discomfort to people with heart disease, children and older adults.
Poor 91-120 Unhealthy May cause breathing discomfort to people on prolonged exposure, and discomfort to people with heart disease.
Very Poor 121-250 Very unhealthy May cause respiratory impact even on healthy people, and serious health impacts on people with lung/heart disease. The health impacts may be experienced even during light physical activity.
Severe 250+ Hazardous May cause respiratory impact even on healthy people, and serious health impacts on people with lung/heart disease. The health impacts may be experienced even during light physical activity.

 

Even at moderate levels, particulate matter can still be harmful to sensitive people. When air pollution levels are lower, the cardiovascular and respiratory health of a person will be much improved, both long and short term. 

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