Impact of Public Transport Strikes on Air Pollution and transport modes Substitution in Barcelona

Many cities in Spain are wrapped in air containing excessive levels of particulate matter, nitrogen dioxide and ozone, generally a problem in big cities caused by traffic. Pollutants largely associated with volume of traffic in urban cities and their outlying areas, such as Madrid and Barcelona, which is suffering from one of the worst levels of air pollution in the country. According to the World Health Organization (WHO), 96.8% of Spain population breathe pollutant air. This paper shows empirical evidence about the contribution of public transport in the air quality of Barcelona using public transport strikes, through econometric analysis based on data from 2008 - 2016. During the study period, there were 147 days affected by some type of public transport strike:bus (57), metro (21), train (71) and tram (4) system, against 4 general strikes. The estimates indicate that public transit strikes have a statistically significant and positive effect on the concentration level of SO2, CO, PM10 and NOX in all over the city, especially in the case of metro and train. These results also allows us to understand better how commuters substitute transports modes between them and what policies can be implemented to increase the use of public transports.