The intake of the blower is situated under the cowl where the windscreen wipers are attached .. the closest exhaust fumes source would be the EGR assembly "valve + actuator + cooling pipe" .. take a look up there, you may find a crack.
The exhaust manifold is not too far off either .. but to check it, you'll need to remove the under tray and get under the car with a torch.
What you'll be looking for.