Environment and EcologyEnvironmental Challenges |
What is the Pollutant Standard Index? |
The U.S. Environmental Protection Agency and the South Coast Air Quality Management District of El Monte, California, devised the Pollutant Standard Index to monitor concentrations of pollutants in the air and inform the public concerning related health effects. The scale, which measures the amount of pollution in parts per million, has been in use nationwide since 1978. The following lists the PS Index and the cautionary status:
PS Index |
Health effects |
Cautionary status |
0 |
Good |
|
50 |
Moderate |
|
100 |
Unhealthful |
|
200 |
Very unhealthful |
Alert: elderly or ill should stay indoors and reduce physical activity. |
300 |
Hazardous |
Warning: general population should stay indoors and reduce physical activity. |
400 |
Extremely hazardous |
Emergency: all people should remain indoors with windows shut and no physical exertion. |
500 |
Toxic |
Significant harm; same as above. |