Air Pollution Index levels scale

Overview

Different countries have their own air quality indices, corresponding to different national air quality standards. Please find air quality index levels scales used in UK, Europe, USA and Mainland China in the sections below. You can get air pollution data for any coordinates on the globe using Air Pollution API.

Air quality index levels scale in UK

Below is a description of UK Air Quality Index levels:

Qualitative name

Index

Pollutant concentration in μg/m3

SO2

NO2

PM2.5

PM10

O3

Low

1

0-88

0-67

0-11

0-16

0-33

Low

2

89-177

68-134

12-23

17-33

34-66

Low

3

178-266

135-200

24-35

34-50

67-100

Moderate

4

267-354

201-267

36-41

52-58

101-120

Moderate

5

355-443

268-334

42-47

59-66

121-140

Moderate

6

444-532

335-400

48-53

67-75

141-160

High

7

533-710

401-467

54-58

76-83

161-187

High

8

711-887

468-534

59-64

84-91

188-213

High

9

888-1064

535-600

65-70

92-100

214-240

Very High

10

⩾1065

⩾601

⩾71

⩾101

⩾241

Air quality index levels scale in Europe

Below is a description of Europe Air Quality Index levels:

Qualitative name

Index or sub-index

Pollutant (hourly) concentration in μg/m3

NO2

PM10

O3

PM2.5

Very Low

0-25

0-50

0-25

0-60

0-15

Low

25-50

50-100

25-50

60-120

15-30

Medium

50-75

100-200

50-90

120-180

30-55

High

75-100

200-400

90-180

180-240

55-110

Very high

>100

>400

>180

>240

>110

Air quality index levels scale in USA

Below is a description of USA Air Quality Index levels:

AQI

Level of health concern

Color

0 to 50

Good

Green

51 to 100

Moderate

Yellow

101 to 150

Unhealthy for sensitive groups

Orange

151 - 200

Unhealthy

Red

201-300

Very unhealthy

Purple

301-500

Hazardous

Maroon

501-1000

Very Hazardous

Brown

For pollutants concentration recalculation into AQI equation and table below is used:

computingaqi

where:

I = the Air Quality index,

C = the pollutant concentration,

Clow= the concentration breakpoint that is ≤C,

Chigh= the concentration breakpoint that is ≥C,

Ilow= the index breakpoint corresponding to Clow,

Ihigh= the index breakpoint corresponding to Chigh.

Ilow-Ihigh

O3, ppb (8-hr)

O3, ppb (1-hr)

PM2.5, μg/m3 (24-hr)

PM10, μg/m3 (24-hr)

CO, ppm (8-hr)

SO2, ppb

NO2, ppb (1-hr)

Сlow-Chigh(avg)

0-50

0-54

-

0.0-12.0

0-54

0.0-4.4

0-35 (1-hr)

0-53

51-100

55-70

-

12.1-35.4

55-154

4.5-9.4

36-75 (1-hr)

54-100

101-150

71-85

125-164

35.5-55.4

155-254

9.5-12.4

76-185 (1-hr)

101-360

151-200

86-105

165-204

55.5-150.4

255-354

12.5-15.4

186-304 (1-hr)

361-649

201-300

106-200

205-404

150.5-250.4

355-424

15.5-30.4

305-604 (24-hr)

650-1249

301-400

-

405-504

250.5-350.4

425-504

30.5-40.4

605-804 (24-hr)

1250-1649

401-500

-

505-604

350.5-500.4

505-604

40.5-50.4

805-1004 (24-hr)

1650-2049

Air quality index levels scale in Mainland China

Below is a description of Mainland China Air Quality Index levels:

AQI

Air pollution level

Air pollution category

0-50

Level 1

Excellent

51-100

Level 2

Good

101-150

Level 3

Lightly polluted

151-200

Level 4

Moderatory polluted

201-300

Level 5

Heavily polluted

>300

Level 6

Severely polluted

An individual score (Individual Air Quality Index, IAQI) is calculated using formula and table with breakpoint concentrations below:

computingaqi

where:

I = the Individual Air Quality index,

C = the pollutant concentration,

Clow= the concentration breakpoint that is ≤C,

Chigh= the concentration breakpoint that is ≥C,

Ilow= the index breakpoint corresponding to Clow,

Ihigh= the index breakpoint corresponding to Chigh.

Individual index

Units are in μg/m3 except CO, which is in mg/m3

IAQI

SO2, 24 hour

SO2,1 hour (1)

NO2, 24 hour

NO2, 1 hour (1)

PM10, 24 hour

CO, 24 hour

CO, 1 hour (1)

O3, 1 hour

O3, 8 hour

PM2.5, 24 hour

0

0

0

0

0

0

0

0

0

0

0

50

50

150

40

100

50

2

5

160

100

35

100

150

500

80

200

150

4

10

200

160

75

150

475

650

180

700

250

14

35

300

215

115

200

800

800

280

1200

350

24

60

400

265

150

300

1600

(2)

565

2340

420

36

90

800

800

250

400

2100

(2)

750

3090

500

48

120

1000

(3)

350

500

2620

(2)

940

3840

600

60

150

1200

(3)

500

Notes

(1) SO2, NO2, CO 1 hour average concentrations are only for real time reporting. For daily reports use 24 hour average concentration.

(2) If the SO2 concentration exceeds 800 μg/m3 use the index from the 24 hour concentration instead.

(3) If the O3 concentration exceeds 800 μg/m3 use the index from the 1 hour concentration instead.