The difference of daily mean AQI between 2020-02-01 ~ 2020-04-30 and 2019-02-01 ~ 2019-04-30.
Use the above drop-down selection to view different pollutants.
The map of China included in our analysis exhibits the distribution of magnitude of air quality improvement during the lockdown period across 100 cities. Each dot represents a city we selected, and the color indicates its degree of air quality improvement. A negative value of difference (blue point) indicates improvement of air quality in 2020 compared to 2019. And a positive value of difference (red point) indicate deterioration of air quality in 2020 compared to 2019.
We can see that most cities with significant air quality improvement tend to cluster in the North China and Yangtze River Delta region. This might be partially explained by the economic structure. Industrial output value accounts for a relatively large proportion of GDP in these two areas. Normally, there are a lot of industrial activities going on there. However, during the lockdown period, nearly all of them were partially or completely suspended. As industry does have an unignorable negative impact on air quality, itโs not difficult to see why notable air quality improvement could be observed in these two regions.