Looking at air pollution maps of big US cities after reading this article is quite scary. Many are at double the amount as London's worst reading and some even

Looking at air pollution maps of big US cities after reading this article is quite scary. Many are at double the amount as London's worst reading and some even three times as high: https://waqi.info/ https://waqi.info/ https://breezometer.com/air-quality-map/air-quality https://breezometer.com/air-quality-map/air-quality