How do you know it's smog caused by diesel? LA has suffered (don't know how is it today) for years from smog and the majority of the vehicles there are petrol. I mean you can't blame it all on diesel.
Back in those days, gasoline/petrol cars had much worse emissions than they do today. They've since been cleaned up a little when it comes to smog-forming emissions. Diesel hasn't.
How do you know it's smog caused by diesel? LA has suffered (don't know how is it today) for years from smog and the majority of the vehicles there are petrol. I mean you can't blame it all on diesel.