A city-level analysis of air pollution, climate and COVID-19 early spread during the Spanish lockdown

The COVID-19 outbreak has escalated into the worse pandemic of the present century. The fast spread of the new SARS-CoV-2 coronavirus has caused devastating health and economic crises all over the world, with Spain being one of the worst affected countries in terms of confirmed COVID-19 cases and deaths per inhabitant. In this situation, the Spanish Government declared the lockdown of the country. The variations of air pollution in terms of fine particulate matter (PM _2.5 ) levels in seven cities of Spain are analyzed here considering the effect of meteorology during the national lockdown. The possible associations of PM _2.5 pollution and climate with COVID-19 accumulated cases were also analyzed. While the epidemic curve was flattened, the results of the analysis show that the 4-week Spanish lockdown significantly reduced the PM _2.5 levels in only one of the cities despite the drastically reduced human activity in good agreement with our previous study of changes in air quality in terms of CO, SO ₂ , PM ₁₀ , O ₃ and NO ₂ levels. Furthermore, no associations between either PM _2.5 exposure or environmental conditions and COVID-19 transmission were found during the early spread of the pandemic.