| Qualitative name | Index | Pollutant concentration in μg/m3 | |||||
|---|---|---|---|---|---|---|---|
| SO2 | NO2 | PM10 | PM2.5 | O3 | CO | ||
| Good | 1 | [0; 20) | [0; 40) | [0; 20) | [0; 10) | [0; 60) | [0; 4400) |
| Fair | 2 | [20; 80) | [40; 70) | [20; 50) | [10; 25) | [60; 100) | [4400; 9400) |
| Moderate | 3 | [80; 250) | [70; 150) | [50; 100) | [25; 50) | [100; 140) | [9400-12400) |
| Poor | 4 | [250; 350) | [150; 200) | [100; 200) | [50; 75) | [140; 180) | [12400; 15400) |
| Very Poor | 5 | ⩾350 | ⩾200 | ⩾200 | ⩾75 | ⩾180 | ⩾15400 |