While you are technically correct when you say that there exists no adequate evidence to support that nitrogen dioxide in itself is carcinogenic, it can still cause cancer nevertheless because it is the main source of an important fraction of PM2.5, which is classified as a Group I carginogenic so thanks for pointing out my mistake I guess, but in the end, cancer will still be cancer no matter how you like it served.All I see here is correlation, not causation, and the correlation exists because the same sources that produce oxides of nitrogen also produce other pollutants (primarily fine particulates, i.e. "soot") that do cause cancer. Don't get me wrong, there are other reasons why oxides of nitrogen are an undesirable pollutant, but you're perpetuating the same sort of error that has many people believing that nicotine causes cancer.
Ambient (outdoor) air quality and health