The number of studies published on COVID-19 in recent months is certainly impressive. However, there are still important gaps to know a great number of characteristics of this disease. Among these, some potential ways of transmission of the SARS-CoV-2 and the different reasons for the severity of the disease in different people. Various studies have suggested that certain air pollutants could be increasing the transmission of the coronavirus, as well as the risks of COVID-19 incidence and mortality. In the present preliminary case-study conducted in Tarragona Province (Catalonia, Spain), we studied the potential association of COVID-19 with PM10, NO2 and O3, as well as the differences in the incidence and lethality of this disease. This Province is divided into two "health regions": Camp de Tarragona, with an important industrial complex, and Terres de l'Ebre, with a great agricultural component. In spite of the notable limitations of the current study, our preliminary findings indicate that the industrialized/urban areas of Tarragona Province show a higher incidence and mortality of COVID-19 than the agricultural/rural zones. These - and previous - results would highlight the importance of conducting specific investigations focused on directly assessing whether air pollutants such as particulate matter can act as carriers of the SARS-CoV-2. If confirmed, the recommendation on keeping the "social distance" (1.5-2 m) might need to be adapted to this situation.