Table 2.
The relationship between CAI value and air pollutants
| Category
|
A
|
B
|
C
|
D
|
|---|---|---|---|---|
| Description
|
Good
|
Moderate
|
Unhealthy
|
Very unhealthy
|
| Values | 0–50 | 51–100 | 101–250 | 251–500 |
| PM10 (µg/m3) | 0–30 | 31–80 | 81–150 | 151–600 |
| PM2.5 (µg/m3) | 0–15 | 16–50 | 51–100 | 101–500 |
| O3 (ppm) | 0–0.030 | 0.031–0.090 | 0.091–0.150 | 0.150–0.600 |
| NO2 (ppm) | 0–0.030 | 0.031–0.060 | 0.061–0.200 | 0.201–2 |
| SO2 (ppm) | 0–0.020 | 0.021–0.050 | 0.051–0.150 | 0.151–1 |
| CO (ppm) | 0–2 | 2.01–9 | 9.01–15 | 15.01–50 |
Abbreviations: CAI, Comprehensive Air-quality Index; PM10, particulate matter with a diameter of less than 10 µm; PM2.5, particulate matter with a diameter of less than 2.5 µm; O3, ozone; NO2, nitrogen dioxide; SO2, sulfur dioxide; CO, carbon monoxide.