This is not a very nice record, but the City of Barcelona has nearly 6,000 per square kilometre, double that of Madrid City and more than three times the figure for London, for example.
And this is only one of the main points about atmospheric pollution in Barcelona.
Another one is that pollution causes 3,500 premature deaths every year, along with 1,800 hospital admissions for cardiorespiratory problems, 5,100 cases of bronchitis in adults, 31,100 cases in children and 54,000 asthma attacks in children and adults.
One out of every three journeys in the city is in a private motor vehicle, over half the vehicles have only one occupant, and the rush hour, when these polluting vehicles are mostly on the street, is in the afternoon, when many city residents go outside to do sport.
Find out more on the Air Quality website, where there is a wide range of information on atmospheric pollution in Barcelona and what you can do to reduce it.