The change won't be for free. But rather than lower the usefulness of cars, make sure new cars have better fuel economies (which directly translates to lower pollution). Within 10-15 years, clunkers get replaced anyways, so a general policy of "by 2027, all newly-registered cars must have a maximum amount of X litres per 100 kilometres" or a ban of Diesel engines outside of speciality markets (military, agriculture, trucks) would hurt virtually no-one (but inefficient car makers, who should improve).

If you hit the poorest, you won't get a ecological paradise, you'll eventually get the next iteration of an autocratic dictatorship (either left-wing or right-wing) - now with the extra support of the industry. No-one needs that.