Three grades and measures of heavily polluted weather

Early warning is divided into three levels, from light to heavy, yellow warning, orange warning and red warning. Early warning measures at all levels are as follows:

1, yellow warning. It is predicted that PM2.5 concentration >: 1 15 μ g/m3 will last for 48 hours or more, and serious pollution will occur in a short time; Or predict that the daily average value of pollutants other than PM2.5 in AQI will last for 48 hours or more, and severe pollution will occur in a short time, which does not meet the high-level warning conditions.

2, orange warning. It is predicted that PM2.5 concentration >: 1 15 μ g/m3 will last for 72 hours or more and PM2.5 concentration >; 150 μ g/m3 will last for more than 24 hours; Or predict pollutants other than PM2.5) daily average >; 200 will last more than 72 hours.

3. Red alert. It is predicted that the daily average value of AQI >: 200 will last for more than 96 hours, and the daily average value of AQI >: 300 will last for more than 48 hours; Or predict that AQI will reach 500 per day.