Air pollution has decreased in urban areas across Europe, as cities continue to be locked down to prevent widespread outbreaks of the coronavirus.
Cities including Brussels, Paris, Madrid, Milan and Frankfurt showed a reduction in average levels of noxious nitrogen dioxide from 5 to 25 March, compared with the same period last year, according to new satellite images.
The images, released by the European Space Agency, show the changing density of nitrogen dioxide, a harmful gas emitted when fossil fuels are burnt at high temperatures, most commonly at power plants and in motor vehicles.
Daily weather events can influence atmospheric pollution, so the satellite pictures took a 20-day average and excluded readings where cloud cover reduced the quality of the data.
In Madrid, average nitrogen dioxide levels decreased by 56% week-on-week after the Spanish government banned non-essential travel on 14 March.
China recorded a drop in nitrogen dioxide pollution in cities during February, when the government imposed draconian lockdown measures to contain the virus.
Pollution over parts of Italy also dramatically fell as the entire country was placed in lockdown
However, in some regions of Poland nitrogen dioxide levels remained relatively high during the period despite its lockdown, perhaps due to the prevalence of coal-based heating.
Countries that went into lockdown later – such as Britain, which did so on 23 March – look set for a pollution reprieve in coming weeks.
Air pollution can cause or exacerbate lung cancer, pulmonary disease and strokes. It causes around 400,000 premature deaths each year in Europe.