According to the classification method in the Technical Regulations of Ambient Air Quality Index (AQI) issued by the Ministry of Environmental Protection, the air quality index (AQI) is between 20 1-300, which is a serious pollution; 30 1-500 is a serious pollution. According to the air quality forecast, and considering the degree and duration of air pollution, the heavy air pollution is divided into four warning levels, which are four, three, two and one from light to heavy, marked with blue, yellow, orange and red respectively, and the first warning level (red) is the highest level.
(1) Level 4 early warning (blue)
1. Health protection reminder measures. Remind children, the elderly and susceptible people such as patients with respiratory tract, cardiovascular and cerebrovascular diseases to reduce outdoor exercise.
(2) Warning Level 3 (yellow)
1. Health protection reminder measures. Remind children, the elderly and susceptible people such as patients with respiratory tract, cardiovascular and cerebrovascular diseases to stay indoors as much as possible and avoid outdoor sports; It is suggested that primary and secondary schools and kindergartens reduce outdoor sports such as physical education class; The general population reduces outdoor sports and outdoor working hours.
(3) Early Warning Level II (orange)
1. Health protection reminder measures. Remind children, the elderly and susceptible people such as patients with respiratory tract, cardiovascular and cerebrovascular diseases to stay indoors as much as possible and avoid outdoor activities; It is suggested that primary and secondary schools and kindergartens stop outdoor sports such as physical education class, recess exercises and sports meetings; The general population should try to avoid outdoor activities; Outdoor activities can take appropriate protective measures such as wearing masks.
(4) Warning level (red)
1. Health protection reminder measures. Remind children, the elderly and susceptible people such as patients with respiratory tract, cardiovascular and cerebrovascular diseases to stay indoors as much as possible and avoid outdoor activities; Primary and secondary schools and kindergartens are closed, and enterprises and institutions can implement flexible working system according to the situation; It is suggested to stop large-scale open-air activities; The general population should try to avoid outdoor activities; Outdoor activities can take appropriate protective measures such as wearing masks.