Modelling COVID19 lockdown impact on the Italian Lombardy region air quality: Assessing of two methods

The Lombardy region was one of the European areas earliest affected by the Coronavirus in 2020, as well as the first area where lockdown measures were enforced. This study aims to investigate the impact of lockdown on air quality for this region of Northern Italy, analyzing a 2 months period. In this work, CAMx and WRF models were used in order to estimate NO2, PM10 and PM2.5 concentrations both during the lockdown and in a business as usual (BAU) situation. NO2, PM10 and PM2.5 concentrations both during the lockdown and in a business as usual (BAU) situation. Model simulations considered two lockdown scenarios, based on different approaches for the assessment of road traffic emissions reduction, in comparison with BAU scenario. The first scenario used emission reduction coefficients computed by the local agency for environmental protection, while the second was based on mobile phone data. We aim to understand whether using these latter data as a proxy could be a promising method for mobility scenario studies.The lockdown offers the opportunity to validate, for the first time ever, modelled scenarios of reduced mobility, proving the reliability of both methods and modelling chain. We take this opportunity by assessing a new approach to support urban mobility, based on a crowdsourcing solution.