I grew up on an old 1950s Forson Dexta with 3 cylinder Perkins Diesel engine blowing exhaust at me. Heck, I spent a whole spring once with no exhaust pipe and it was literally blowing right in my face. It was annoying but obviously not deadly. Harmful?
My new Yanmar diesel tractor vents the exhaust under the engine instead of on a stack like my old Dexta. You would think this would allow even more exhaust to make it to the driver. I'm still not sure what the logic is for mounting the exhaust under on newer diesel tractors.