Sounds like the typical and pervasive deniers argument. “we’ve gone too far “.
The science is clear with regard to health effects of airborne particulates and Diesel exhaust, so let’s not debate that here. It gets to be an argument similar to religion and science, where one side argues fact and the other emotion and opinion.
Anecdotal for sure, but every time I have a chest X-ray, the first question is “when did you stop smoking?”
I smoked a total of three cigarettes in my life, back in college, but I worked in a Diesel R&D laboratory environment for thirty five years, with 40 engines running 24/7. I am sure the scarring on my lungs are related to that exposure.
An inordinate number of my co workers have died from leukemia or respiratory issues.
The primary issue with the introduction of ulsd was that the aromatic makeup of the fuel is different, because of the hydrocracking process employed in removing sulfur.
The change in aromatic causes the old seals, conditioned with the old fuel, to harden and shrink, causing leaks.
New seals are compatible with the ulsd. That bridge has been crossed by now, though.
The lubrcity issue is overblown. Prior to the introduction of ulsd, there was no universally recognized standard for lubricity. Actual lubricity was all over the map, and some refineries employed hydro cracking years ago.
A lower limit spec was established with the widespread adoption of ulsd to address this.
European are fuel, if I recall (i’ve been out of this for many years since I retired) has a higher spec for lubricity . US fuel producers and suppliers refused to implement the higher spec, although we in the Diesel industry lobbied heavily for it at the time.