How Pollution Has Decreased in Spain with the State of Alarm

The state of alarm enacted in Spain has caused an industrial shutdown and the elimination of most road transport. Obviously, this decrease in human activity has caused the contamination produced by vehicles and industries to fall very noticeably. This is not only happening in Spain: across the rest of Europe and even on other continents, an improvement in air quality has been detected as a result of these exceptional circumstances.

But how can we quantify all this decrease in human activity in the overall state of pollution in our country? Several studies have been carried out to determine how the drop in environmental pollution has occurred, and it is certainly one of the few positive things we can find in this situation.

Less activity, less pollution

The quantity of particles suspended in the atmosphere can be measured thanks to satellites such as the Sentinel-5P from the Copernicus programme. This satellite is responsible for taking images of Europe, and among its functions is carrying out measurements of nitrogen dioxide (NO2) in the atmosphere, as demonstrated by these images provided by the Sinc agency.

To accurately determine this reduction in this pollutant, a time window from 16 to 25 March was taken, a 10-day period that allows comparison with the average pollution during 2019. It is a clear way to observe the drop in pollution, because the difference can be seen between several months and this short but very descriptive period of the current situation.

The largest differences can be seen in big cities. Madrid, Barcelona and Valencia have experienced a considerable drop in the amount of nitrogen dioxide. The absence of car journeys and the restriction of heavy transport help to eliminate pollution. This situation is repeated in other large European cities such as Paris, Milan or Rome. But the causes of this drop in pollution are not limited to the reduction of road traffic.

In February, flights were at their usual level, but on 29 March far fewer flights were recorded in global airspace. This has also helped reduce the presence of polluting gases in the atmosphere. The cleaner air around cities is something we take away from this strange confinement, and it will leave us a period to breathe better and without all those polluting gases that, under normal conditions, make our cities considerably harder to breathe in.