Reasons for the change of daily average value of pm2.5 in Beijing and Shanghai

The reasons for the daily average value of pm2.5 in Beijing and Shanghai are industrial emissions, traffic emissions and weather conditions.

1. industrial emissions: industrial production is one of the main sources of PM2.5. Both Beijing and Shanghai are economically developed cities with large industrial emissions, which is also a reason for the high annual daily average value of PM2.5.

2. Traffic emissions: Traffic is another main source of PM2.5. Both Beijing and Shanghai are big cities with high traffic density and high traffic emissions, which is one of the reasons for the high daily average value of PM2.5.

3. Weather conditions: The geographical location and climatic conditions of Beijing and Shanghai will also affect the daily average value of PM2.5. For example, the low temperature and low wind speed in winter are easy to form a greenhouse effect, and the concentration of PM2.5 will increase accordingly.