Categories

Breakpoints for each pollutant

AQI

Sub-Index

O₃ (ppm)

8-hour

PM10 (µg/m³ )

24-hour

CO (ppm)

24-hour

SO₂ (ppm)

24-hour

NO₂ (ppm)

24-hour

Good

0 - 50

0.0 - 0.03^a

0.0 - 90

0.0 - 4.0

0.0 - 0.03

0.0 - 0.03

(0.0 - 0.064)^b

(0 - 54)

(0.0 - 4.4)

(0.0 - 0.034)

(^c)

Moderate

51 - 100

0.031 - 0.06

90.1 - 350.0

4.1 - 8.0

0.031 - 0.06

0.04 - 0.05

(0.065 - 0.084)

(55 - 154)

(4.5 - 9.4)

(0.035 - 0.144)

(^c)

Unhealthy for

sensitive groups

101 - 150

0.061 - 0.092

(0.085 - 0.104)

350.1 - 431.3

(155 - 254)

8.1 - 11.7

(9.5 - 12.4)

0.061 - 0.182

(0.145 - 0.224)

0.06 - 0.30

(^c)

Unhealthy

151 - 200

0.093 - 0.124

(0.105 - 0.124)

431.4 - 512.5

(255 - 354)

11.8 - 15.4

(12.5 - 15.4)

0.183 - 0.304

(0.225 - 0.304)

0.31 - 0.55

(^c)

Very Unhealthy

201 - 300

0.125 - 0.374

(0.125 - 0.404)

512.6 - 675.0

(355 - 424)

15.5 - 30.4

(15.5 - 30.4)

0.305 - 0.604

(0.305 - 0.604)

0.65 - 1.04

(0.65 - 1.24)

Hazardous1

Hazardous2

301 - 400

401 - 500

0.375 - 0.504

(0.405 - 0.504)

0.505 - 0.604

(0.505 - 0.604)

675.1 - 837.5

(425 - 504)

837.6 - 1000

(505 - 604)

30.5 - 40.4

(30.5 - 40.4)

40.5 - 50.4

(40.5 - 50.4)

0.605 - 0.804

0.605 - 0.804)

0.805 - 1.004

0.805 - 1.004

1.05 - 1.54

(1.25 - 1.64)

1.55 - 2.04

1.65 - 2.04