It's not just cars, standards matter. Have a look here. https://waqi.info/#/c/29.217/70.608/3.8z https://waqi.info/#/c/29.217/70.608/3.8z And that is just the

It's not just cars, standards matter. Have a look here. https://waqi.info/#/c/29.217/70.608/3.8z https://waqi.info/#/c/29.217/70.608/3.8z And that is just the things we regularly monitor, think of all the toxic crap several industrial process may be releasing.