Nathan,

Well, in order to do something like that, you would have to place something almost as small into the lungs of a living person. The problem is not the chemistry of trapping the particles--that could be easily accomplished. The problem is doing so while doing no further harm to a person. This is a BIG problem, and actually it would be unethical to even test it. So no, it does not exist is most likely will not exist. To put it another way, when you worked on your aquarium, you probably took the fish out for a time. Otherwise, the fish could have been in jeopardy.

Given that, our best protection is an engineering control--get badly tuned diesels off the road. But this won't happen either because of economics. We could try to put some sort of filter on the engine, but again that has economic costs and efficiency costs which probably make it prohibitive.

Here are the possible controls:

--One engineering control is already there--use side streets and bike paths that are away from diesel engines.

--An administrative control of keeping distance and limiting time of exposure is also very practical. We can ride when the traffic is light. We can stay away from heavy traffic.

--Or, we can use what in the safety profession is known as PPE (personal protective equipment); in this case, a respirator as we discussed above.

I hope this helps.

John