Opening mobile phones to check the AQI index before going out every day has become a compulsory course for people in morden city. When the AQI is lower than 50, we hang out with friends to enjoy the sunshine and the warm wind. When the AQI breaks through 300, we armed ourselves with a mask, try not to close the door, and be an otaku at home with...

What are the benefits of using PM2.5 and not AQI to measure air quality, and what difference does it really make? PureLiving explains:

Part-I The Different Measures

AQI stands for "Air Quality Index” and rates air quality on a 0 - 500 scale, with 0 being the best, and 500 representing the worst. This method was introduced to China by the US...