I’m interested to know if anyone knows the answer to these questions:
1) How much pollution, of what kinds, are produced during the manufacture of catalytic converters?
2) How much finely divided platinum exits the exhaust pipes of cars equipped with catalytic converters, or otherwise enters the environment as a consequence of their use? *
3) What is the ultimate destination of that finely divided platinum, and how long does it spend in what places on its way there?
4) If, as I assume, a fair amount of it finds its way into the air as very fine particles, and then into our lungs, what happens to it there, and what are its effects? I have a small suspicion that it may remain there indefinitely, since it’s inert and insoluble; and that it is very probably carcinogenic, since it is likely to catalyse all sorts of biologically abnormal reactions.
I’d love to be reassured on all these points, but I’d be surprised if anyone honestly can.
* Update, 2014: lots. There have recently been news reports suggesting that road dust now contains so much platinum (and rhodium) dust that it would be an economic proposition to recover it.