Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The breakpoints used to define sub-indices (standard index for noise measurements).
| PSI values | Index category | Equivalent noise levels (dBA) | Noise description |
|---|---|---|---|
| <100 | Very good quality | 20 | Very quiet |
| 100 | Good quality | 50 | Quiet |
| 200 | Satisfactory | 70 | Noisy |
| 300 | Unhealthy | 90 | Very noisy |
| 400 | Hazardous | 100 | Unbearable |
| 500 | Seriously Hazardous | 130 | Seriously Hazardous |
