"The Covid lockdown has emptied and silenced city streets. Is it inevitable that they will return to noisy thoroughfares full of vehicles belching exhaust gases into the urban air? Why do we continue to support policies that slowly choke the urban environment and those who live and work within it?
Air pollution in the urban environment is a silent killer. In 2016, the World Health Organisation published a comprehensive report that assessed the level of exposure and the burden of disease resulting from ambient air pollution in 3000 large cities around the world. The survey measured levels of exceptionally fine particulate matter, called PM2.5, which is a reliable indicator of overall air quality. There is no safe level of this pollutant—no threshold has been identified below which no damage to health is observed."
Photo from Climatezone.org website