Role of Vehicular Emissions in Urban Air Quality: The Covid-19 Lockdown Experiment

•- A drop of 30% for NO2 & PM2.5 associated with drop of 70% in vehicle count in London.•- Multicity air contaminant – traffic count elasticity of 0.71 for NO2 & 0.56 for PM2.5.•- Multicity elasticity shows traffic emissions drop to consistently reduce NO2 & PM2.5.•- This methodology enables to quantify the benefits of urban mobility electrification.