Forest Fire Smoke Categories and Breakpoints

Air Quality Rating PM2.5 24-hour Average (micrograms/m3) PM2.5 8-hour Average (micrograms/m3) PM2.5 1-hour Concentration (micrograms/m3) Visibility (miles)9
GOOD 0.0-15.4 

0.0-17.1

0.0-20.0

20+
MODERATE

15.5-25.4

17.2-30.0

20.1-40.0

10-19
UNHEALTHY for Sensitive
Groups (UFSG)

25.5-35.4

30.0-50.0

40.1-94.2

5-9
UNHEALTHY

35.5-46.4

50.0-65.7

94.3-120.0

3-4
VERY UNHEALTHY

46.5-100.4

65.7-143.0 120.0-250.0 1-2
HAZARDOUS

>100.4

>143.0

>250.0

<1