Table 1 Grading standard and health recommendation of AQI
| AQI | AQI level | Concentration of primary pollutant (ug/m3) | Classification of AQI & representative color | Effect | Recommendation | |
|---|---|---|---|---|---|---|
| 0–50 | Grade1 | 0–35 | Excellent | Green | Almost no air pollution | All individuals can take normal activities |
| 51–100 | Grade2 | 35–75 | Good | Yellow | Some pollutant have weak impact on some sensitive individuals | The sensitive individuals should reduce outdoor activities |
| 101–150 | Grade3 | 75–115 | Slight pollution | Orange |
Symptoms are aggravated in susceptible population; Irritative symptoms show in healthy individuals | Children, the elderly and people with cardiopulmonary diseases should reduce long-term and high-intensity outdoor exercise |
| 151–200 | Grade4 | 115–150 | Moderate Pollution | red |
Symptoms are further aggravated in susceptible population; Some influences on cardiopulmonary system are shown in healthy individuals |
Children, the elderly and people with cardiopulmonary diseases should avoid l long-term and high-intensity outdoor exercise General population should moderately reduce outdoor activities |
| 201–300 | Grade5 | 150–250 | Severe pollution | Purple |
Symptoms are significantly aggravated in patients with cardiopulmonary diseases; Symptom are shown generally in healthy individuals |
Children, the elderly, the people with heart disease or respiratory disease should avoid outdoor activities General population should reduce outdoor activities |
| > 300 | Grade6 | 250–500 | Extremely severe pollution | maroon |
Tolerance of exercise decreased with obvious symptoms in healthy individuals; Some diseases appears in advance |
Children, the elderly and patients should stay indoor General population should reduce outdoor activities |