Recently smogged

My opacity readings were at 8.5%. The tech said other TDI's get 0-0.5%. Everything is running good except I have a burned out catalytic converter (my guess after more smoke showing up after a turbo loss and catalytic oil drenching). I did pass, as 30% is the mark.

I think the convertor is the main remover of particulate matter, i.e. soot.

Does that mean that the convertor is supposed to burn the soot down to CO2?

Does it do anything for NOx (nitrous oxides)?

As far as I know of, diesel cat's currently do nothing for NOx (or very little when compared to gasoline cats). I'm not sure what the cat does on our cars, but I don't think it does anything for the soot, just helps with CO emissions and unburned hydrocarbons.