Green plants gobble up CO2 during the day, and turn it into biomass.
So plants metabolise CO2 within 5 minutes – and do Molecular Nuclear Fusion, so building biomass. Capping global average CO2 at 2 parts per million: any person who thinks photosynthesis on the land and sea would allow a rise in global average CO2, in a nuclear funded idiot.
Such people should never have been in education. The limit to plant growth on land is available organic nitrogen. Pees use bacteria to fix N. Farmers spray NH4 chemical fertilizer on the land. Very expensive, and energy dense to produce.
Car engines, both petrol and diesel produce NO and NO2 – NOx. They are not an important source. A million times more important is lightening. Followed by wood fires.
This fertilizes natural plant life. Near schools, or stationary in town, exhausts want a water mist, to was out emissions as H2CO3, H2NO2, H2NO3, H2SO3. The emission then fall harmlessly to the ground, and run into the sewers.
So diesel cars go around increasing plant life: they do not pollute – they spread life.