Bought my son a new Nevara a few months ago and when he accelerates, it blows out unburnt diesel. Nissans answer is "that's normal". How much garbage is it blowing out that we cant see?

Ive got a DMax and don't know what their pollution track history is, but I watched from behind as someone else drives it without black smoke and my 'van and fittings round the exhaust pipe has very little soot on it - cant see it, but will leave slight marks on your hand. But of course its what we cant see in the way of emissions.....