Do climate and air pollution influence the transmission and incidence of the new COVID-19 disease?

The COVID-19 pandemic and the mobility limitations imposed to try to contain its spread have led to a drastic decrease in emissions of air pollutants and CO2. For the former, the drop in the atmospheric concentrations of the main urban air pollutants leads to a decrease in mortality attributable to air pollution. This has not been the case in the case of CO2 emissions; though they have decreased by close to 8%, that is insufficient to show a measurable impact in the context of the climate crisis. On the other hand, social distancing measures can have counterproductive effects on other prevention systems related to health effects aggravated by climate change, such as in the case of heat waves. 

Moreover, there is no clear evidence that other environmental factors such as temperature, humidity or UV radiation can influence the spread of the new virus or slow down its transmission, having a comparatively small weight in relation to the public health measures implemented to contain the virus. However, local air pollution does appear to be a factor that can aggravate the disease and increase its lethality. Its possible role in the spread of the virus has yet to be proven. Finally, it should be noted that the scientific evidence in relation to the interaction of SARS-CoV-2 (the virus that causes the COVID-19 disease) with environmental factors is very limited and in many cases it is based on ecological studies that do not allow inferring causality. 

Therefore, it is necessary to carry out more in-depth research, with other types of epidemiological designs, more extensive data series and controlling for confounding factors not considered so far, which will help to acquire a more rigorous scientific knowledge regarding the behaviour and spread of COVID-19.