Pollutant concentrations for the Daily Air Quality Index (DAQI)
Published 19 December 2025
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Air pollution is communicated on the Daily Air Quality Index (DAQI), a simple scale that explains the short term health risk of air pollution in words, numbers and colours.
Each pollutant has different concentrations at each DAQI level. Pollutant levels are measured in micrograms per cubic metre (µg/m3).
Particulate matter (PM2.5)
PM2.5 levels are based on the daily mean concentration for historical data, or the latest 24 hour running mean for the current day.
| DAQI level | DAQI band | PM2.5 levels (µg/m3) |
|---|---|---|
| 1 | Low | 0 to 11 |
| 2 | Low | 12 to 23 |
| 3 | Low | 24 to 35 |
| 4 | Moderate | 36 to 41 |
| 5 | Moderate | 42 to 47 |
| 6 | Moderate | 48 to 53 |
| 7 | High | 54 to 58 |
| 8 | High | 59 to 64 |
| 9 | High | 65 to 70 |
| 10 | Very high | 71 or more |
Particulate matter (PM10)
PM10 levels are based on the daily mean concentration for historical data, or the latest 24 hour running mean for the current day.
| DAQI level | DAQI band | PM10 levels (µg/m3) |
|---|---|---|
| 1 | Low | 0 to 16 |
| 2 | Low | 17 to 33 |
| 3 | Low | 34 to 50 |
| 4 | Moderate | 51 to 58 |
| 5 | Moderate | 59 to 66 |
| 6 | Moderate | 67 to 75 |
| 7 | High | 76 to 83 |
| 8 | High | 84 to 91 |
| 9 | High | 92 to 100 |
| 10 | Very high | 101 or more |
Nitrogen dioxide (NO2)
Nitrogen dioxide levels are based on the hourly mean concentration.
| DAQI level | DAQI band | NO2 levels (µg/m3) |
|---|---|---|
| 1 | Low | 0 to 67 |
| 2 | Low | 68 to 134 |
| 3 | Low | 135 to 200 |
| 4 | Moderate | 201 to 267 |
| 5 | Moderate | 268 to 334 |
| 6 | Moderate | 335 to 400 |
| 7 | High | 401 to 467 |
| 8 | High | 468 to 534 |
| 9 | High | 535 to 600 |
| 10 | Very high | 601 or more |
Ozone (O3)
Ozone levels are based on the running 8 hour mean concentration.
| DAQI level | DAQI band | Ozone levels (µg/m3) |
|---|---|---|
| 1 | Low | 0 to 33 |
| 2 | Low | 34 to 66 |
| 3 | Low | 67 to 100 |
| 4 | Moderate | 101 to 120 |
| 5 | Moderate | 121 to 140 |
| 6 | Moderate | 141 to 160 |
| 7 | High | 161 to 187 |
| 8 | High | 188 to 213 |
| 9 | High | 214 to 240 |
| 10 | Very high | 241 or more |
Sulphur dioxide (SO2)
Sulphur dioxide levels are based on the 15 minute mean concentration.
| DAQI level | DAQI band | SO2 levels (µg/m3) |
|---|---|---|
| 1 | Low | 0 to 88 |
| 2 | Low | 89 to 177 |
| 3 | Low | 178 to 266 |
| 4 | Moderate | 267 to 354 |
| 5 | Moderate | 355 to 443 |
| 6 | Moderate | 444 to 532 |
| 7 | High | 533 to 710 |
| 8 | High | 711 to 887 |
| 9 | High | 888 to 1,064 |
| 10 | Very high | 1,065 or more |