Research Article
Study on Spatial Temporal Distribution Characteristics of Air Quality Index in Beijing and Its Correlation with Local Meteorological Conditions
| Air quality index range | Air quality level | Air quality index category | Represent color |
| 0∼50 | Level one | Excellent | Green | 50∼100 | Level two | Good | Yellow | 100∼150 | Level three | Mild pollution | Orange | 150∼200 | Level four | Moderate pollution | Red | 200∼300 | Level five | Heavy pollution | Purple | >300 | Level six | Severe pollution | Maroon |
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