The EU has limits for suspended particulate matter, and at least in Germany all the major cities are battling to stay within the thresholds. A few cities ban diesel vehicles in the city, others put expensive air purifiers next to the measuring stations.
People seem to love their cars more than their health, and other measures like modernizing heating don't seem to have much traction.
What I observed in my area is that people are not loving cars more than their health, but they cannot make a difference at a personal level, many don't want to change anything and then people who care stop believing anything can be done and give up. Air pollution is not a fire you can extinguish in 15 minute and move on, it is mass phenomenon with millions of tiny participants, it is the death of the thousand cuts and no individual can change it alone.
Maybe something where everyone can choose a person with similar values as themselves, and the person that's chosen by the most people will deal with all the details and day-to-day stuff. And it would be good if we had such a thing both for nationwide problems and for local issues, so we can solve problems both locally and on a larger scale.
People seem to love their cars more than their health, and other measures like modernizing heating don't seem to have much traction.