NOx pollutants is directly related to the heat of combusion. The adjustments you mention would definatley help with particulates but would not decrease the production of NOx much.
If you live in God’s country like I do, NOx pollution is not much of an issue but in congested urban areas, it is the NOx that makes your eyes burn when you walk out the door. NOx will also exacerbate asthma, this is actually an important invention if it works.