Barcelona’s NO₂ levels dramatically reduced by Low Emission Zone

Barcelona’s NO₂ levels dramatically reduced by Low Emission Zone

Five years after Barcelona introduced its low-emission zone (LEZ), researchers have found that the measures have reduced nitrogen dioxide levels by nearly 8 µg/m³. The study used a sophisticated synthetic control method to isolate the LEZ’s impact from two major confounders: the COVID-19 pandemic and everyday weather variability. By comparing air quality at stations inside the 95 km² restricted zone with control stations far outside it, the team…