Nitrogen dioxide (NO2) emitted by cars is exactly the gas that drops in large quantities. In Pamplona/Iruña and Alsasua/Alsasua, for example, reductions of more than 80 per cent have been recorded. Ten areas of Navarra have meters for controlling this type of contamination, of which Pamplona, Tudela, Villanueva de Aezkoa and Alsasua have been the most affected, according to Diario de Noticias.
In Altsasu/Alsasua, for example, there has been an 86% drop, from 29 to 4 micrograms of NO2 in the air. In addition, the largest number of casualties have occurred in Pamplona/Iruña. The 11 of March was more contagious than usual and since then and until 19 March there was an 82% decrease in the Plaza de la Cruz de Pamplona, with a 67% decrease compared to the 12 of March, which was more common. In the Iturrama neighborhood, the decrease was 83% and in the Rochapea it was 75.6%. In Tudela, there are two meters and the one with the largest decrease has been 56.25%, according to the data provided.
These decreases in pollution were also frequent in China and elsewhere. With data from last Tuesday, Greenpeace estimates that in a week there was a 45% decrease in Barcelona and a 75% decrease in Madrid. Data from Navarre can be found on the Navarre air quality measurement website.