Figure 4

Time-series NO2 variations between observed and predicted NO2 of 145 air stations before and during lockdown calculated using DTW. (a) NO2 variations before lockdown; (b) NO2 variations during lockdown. High values of NO2 variations represent greater changes among observed and predicted NO2. The maps are performed using ArcGIS Pro software (version 2.7, https://www.esri.com/en-us/arcgis/products/arcgis-pro/overview).