The results of an international study on the effects of the Covid-19 lockdown on air quality in twelve European cities have been published in the scientific journal PLOS ONE. Prof. Giorgio Guariso of the Department of Electronics, Information and Bioengineering of the Politecnico di Milano is one of the authors.
The extremely particular conditions that occurred in the first half of 2020 actually constitute the greatest air quality experiment ever carried out and make it possible to evaluate the effects on the levels of air pollution of an almost total blockage of urban traffic and of many activities and services.
The study shows that, even considering the specific weather conditions of the lockdown period, concentrations of fine particulate matter PM2.5, the most critical for health effects, did not decrease in various cities such as Milan and Brussels. On the contrary, nitrogen oxide concentrations decreased everywhere, which in most cases led to an increase in ozone concentrations.
This demonstrates, on the one hand, the need to address air pollution problems by considering the specific characteristics of each situation and, on the other hand, that typical traffic reduction measures do not always lead to significant results.