These are the findings of a study by the Barcelona Public Health Agency, analysing the evolution of air pollution levels in the area of the Glòries tunnel and comparing them with the results from the fixed station in L’Eixample, operated by the Air Pollution Monitoring and Forecasting Network in Catalonia. This is the reference station for roads carrying large volumes of traffic, such as the Gran Via.

Levels of these pollutants were studied during the construction stage (from 6 January 2018 to 5 November 2021), during the time the tunnel was open in one direction (from 6 November 2021 to 23 December 2021), and finally, when the tunnel was open in both directions (from 25 May 2022 to 7 June 2022). The data recorded during the State of Emergency for Covid-19 was not taken into account, as the mobile unit was inactive during this time.

Healthier and quieter environment

In terms of levels of NO2, a pollutant linked to exhaust fumes, this dropped by 39% between the construction period and the completion and opening of both tunnels. Compared to data from the Eixample monitoring station, NO2 levels at the tunnel in Glòries are now down by 4.8%.

As for PM10 particles, linked to emissions generated by the works, these levels have also dropped since the work was completed and the tunnel opened. In this case the reduction was 7.6%, with current figures coming out 13.2% lower than the figures at the Eixample monitoring station.

When it comes to noise levels, the section of the Gran Via where traffic has been shifted below ground has seen decibel levels drop from 74 to 65. This drop in noise pollution puts the area on par with noise levels in pedestrian areas in the city.