Analysis of the effect of COVID-19 on air pollution: perspective of the Spanish case

The pandemic caused by coronavirus COVID-19 is having a worldwide impact that affects health and the economy and indirectly affects air pollution in cities. In Spain, the effect has evolved from being anecdotal in January 2020 to become the second country in Europe with the highest number of cases (614,000 cases by 17/09/2020), which has affected the health system and caused major mobility restrictions. In contrast, COVID-19 has affected air pollution and energy consumption in the country. This article analyzes the indirect effect produced by this pandemic on air pollution, referenced to various stages that occurred in Spain: first stage, without public awareness of COVID-19 impact (mid-January 2020); second is when Spanish Government alerted (late February 2020); and third, after the decree of alarm and mobility restriction of citizens by the government (March 2020) along with the various phases of the de-escalation. The indirect effect produced by this pandemic on air pollution in Spanish cities has been resulted in a decrement of 70% to 80% of average, taking into account dates after the decree of alarm and mobility restriction by the Spanish government (14/03/2020), compared to days prior to that date. Thus, the results of this analysis indicate a significant alteration in air pollutants; these alteration patterns have followed similar paths over different countries worldwide improving the air quality as discussed by Dutheil et al. (Environ Pollut (Barking, Essex: 1987) 263:114466, 2020).