The City of Barcelona It has reached an unprecedented peak of nitrogen dioxide (NO2) contamination this Thursday at 11 am since the declaration of the state of alarm by coronavirus on March 14, exceeding the maximum levels established by the European Union (EU) in six of its eight measuring stations.
Specifically, according to data from the Generalitat, the Grace (122 micrograms per cubic meter), Eixample (120), Ciudadella (114), Poblenou (77), Vall d’Hebron (65) and Sants (55) in the morning of May 21, they have exceeded the annual European limit of 40 micrograms of NO2 per cubic meter of air. These are the highest pollution values detected in the Catalan capital since the start of the confinement by Covid-19, although it is not the first time that the city has exceeded the limits of the EU during the state of alarm: since last Monday. It has happened more than 40 times (one measurement per hour).
The reduction in traffic during the first two months of confinement have favored record lows of NO2 contamination in the city of Barcelona: the data for March and April this year have been, according to data from the Barcelona Contamination platform, the lowest since data are available -19 and 27 micrograms per cubic meter, respectively-.
The anticyclone
However the increased circulation of cars and trucks in recent days they have directed the city to levels of pollution similar to those before the confinement: “We are still below the levels that existed before the state of alarm, but traffic has already grown by 30% since its lowest point in recent months “, explained the coordinator of Contaminació Barcelona, Miquel Ortega.
The increase in pollution in Barcelona this Thursday may be due, according to Ortega, to two factors: an increase in emissions caused by road traffic, and atmospheric conditions that prevent the dispersion of polluting gases that are produced at street level.
“Since last Monday we have an anticyclone on top that makes pollution not spread; something that, together with the progressive increase in the volume of traffic, makes emissions are going up and they have reached their maximum in the confinement “, has exposed this physicist and ambientologist.
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