Impact of fare-free public transport on air pollution in Genoa: a comparative study

I study the impact on air pollution of a partial fare-free public transport (FFPT) scheme introduced in the Italian city of Genoa starting in December 2021. This measure allows users to access a part of the public transport network for free. The local government introduced the measure with the aim of discouraging private vehicles usage and improving air quality. I empirically evaluate the effectiveness of the policy, specifically its effect on PM10 concentration, a key air pollution indicator. I conduct a comparative analysis using longitudinal data from Genoa and other Italian cities that did not implement a similar measure. I build a synthetic control to replicate the concentration of PM10 in the air in the city of Genoa, and I use it as a counterfactual to measure the treatment effect. The data reveal a 11.72% reduction in the average PM10 concentration in Genoa after the introduction of FFPT. However, the model suggests that this decrease is primarily due to better weather conditions and other covariates, while the impact of FFPT appears to be limited or possibly negligible.