Do Air Pollution and Meteorological Variables Have a Bearing on COVID-19 Mortality? Benchmarking of Time Series between the First and Second Waves in Nine Spanish Provinces

ABSTRACT

Some pollutants like PM10, NO2 and O-3 are detrimental to people's health, as numerous studies have shown, and they are related to short-term and long-term mortality. A sample of 9 out of the 52 Spanish provinces was studied. Generalized linear models (GLM) with a Poisson link function were developed during the time periods corresponding to the first and second waves of the daily average values of the independent variables (PM10, NO2 and O-3, as atmospheric pollutants, and meteorological variables such as the daily maximum temperature and the absolute humidity) versus the dependent variable (COVID-19 mortality rate, or CMR) during said first and second waves. Statistically significant lags between the independent variables and the dependent variable were established. The associated relative risks were calculated from the estimators obtained in the GLMs, with increases of 10 mu g/m(3) for atmospheric pollutants, 1 degrees C for the maximum temperature and 1 g/m(3) for the absolute humidity. The results show that NO2 has a stronger relationship with the CMR than the other air pollutants. The meteorological variables examined did not show a robust relationship between both waves, which indicates that they played a minor role in the CMR. In conclusion, air pollutants such as to NO2 and PM10 had a statistically significant relationship with the CMR, although it is limited and subordinate to other factors such as the public health measures that were taken, the presence of comorbidities and the age of the patient.