At a time when my sniffer isn't working as well as it did when I was younger, I seem to be more sensitive to Diesel and other exhaust fumes. I really notice this more this time of year when I'm driving in my car with the heater on. If I get behind a Diesel pickup, the heater intake is apt to suck up some of those exhaust fumes and route them right into the passenger compartment. During warmer weather, I can roll up the windows and escape from most of these fumes. I try to avoid driving behind Diesel-powered pickups and the few cars that are around; the big rigs don't seem to bother me as much but maybe that's because their exhaust stacks are often routed up higher.
I've never owned a Diesel-powered personal vehicle and likely never will. I understand that they deliver better fuel economy than gasoline and produce more torque but these attributes do not interest me. I'm turned away from them primarily because they are noisey and smokey. They tend to last a long time, but from the people I've known who've had them, when something does go wrong the repair bill can be many times that for repairs made to a gasoline engine.
Then there is the subject of driver technique. With big rigs, there isn't much issue with excessive accelleration, but with smaller Diesel-powered rigs there can be. Hot dog drivers with a Diesel are just as apt to tromp on the throttle as they would in a gasoline-powered car, which of course creates an even greater burst of smoke. As I understand it, the fuel economy of a Diesel is optimal (even moreso that with a gas engine) with even, gradual accelleration.
Be prepared for an increasing number of Diesel-powered personal vehicles in the future. The US government likes the idea because of the increase in fuel economy (even if Diesel often costs a little more).
I wonder how all the "Green attitude" in Europe squares with their much wider use of light vehicles powered by Diesel. A great many smaller cars there have Diesel engines. When you're in the city, those streets can be like canyons, with breezes blocked off and no relief from the clouds of Diesel smoke.
My other complaint about fumes comes from old Ford trucks that have outlived their time. These would be gas-powered, older F-100's, F-150's, and F-250's. Whenever I see one of these ahead of me on the road, I groan inwardly and know that I am about to be treated to a big, long sniff of semi-burned raw gasoline fumes. Rarely am I disappointed. These old Ford pickups with carburetors just seem to have lasted longer than anyone ever anticipated. They mostly have FE series engines; big, heavy, gas-guzzler V-8's that by now have worn-out carburetors, all kinds of crankcase blow-by, and in general, are quite tired. But they keep running so the owners "cling to them" (sound familiar?). In this region anyway, by far and away, Ford sold the most pickups in decades past, so the original numbers of Chevrolet (and GMC) and especially Dodge were smaller. Given the greater propensity for rust, the GM products didn't last as long regardless of how good the engines might be. So it's the old Ford pickups that drive me nuts with fumes.
It's funny that the Ford pickups would be so long-lived, as the heavier trucks in their product line have tended to have presented the opposite experience. Professional operators that I've known have not particularly liked heavier Ford trucks, to include C-600's, C-750's and the conventional cab types in comparable weights. Forget about over-the-road trucks; Ford gave up trying to make and sell those some time ago.