Effects of air pollution and climatology on COVID-19 mortality in Spain

The health, economic, and social impact of COVID-19 has been significant across the world. Our objective was to evaluate the association between air pollution (through NO2 and PM2.5 levels) and COVID-19 mortality in Spanish provinces from February 3, 2020, to July 14, 2020, adjusting for climatic parameters. An observational and ecological study was conducted with information extracted from Datadista repository (Datadista, 2020). Air pollutants (NO2 and PM2.5 levels) were analyzed as potential determinants of COVID-19 mortality. Multilevel Poisson regression models were used to analyze the risk of mortality after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Models were adjusted by four climatic variables (hours of solar radiation, precipitation, daily temperature and wind speed) and population size. The mean levels of PM2.5 and NO2 across all provinces and time in Spain were 8.7 mu g/m(3) (SD 9.7) and 8.7 mu g/m(3) (SD 6.2), respectively. High levels of PM2.5 (IRR = 1.016, 95% CI: 1.007-1.026), NO2 (IRR = 1.066, 95% CI: 1.058-1.075) and precipitation (IRRNO2 = 0.989, 95% CI: 0.981-0.997) were positively associated with COVID-19 mortality, whereas temperature (IRRPM2.5 = 0.988, 95% CI: 0.976-1.000; and IRRNO2 = 0.771, 95% CI: 0.761-0.782, respectively) and wind speed (IRRNO2 = 1.095, 95% CI: 1.061-1.131) were negatively associated with COVID-19 mortality. Air pollution can be a key factor to understand the mortality rate for COVID-19 in Spain. Furthermore, climatic variables could be influencing COVID-19 progression. Thus, air pollution and climatology ought to be taken into consideration in order to control the pandemic.