Andrew,

Unfortunately, the concept of on electrostatic filter on the spokes would not do well unless your nose was within about an inch of the wheel, and the wind was blowing through the wheel. Even then, it probably would miss a huge amount of particles in the air. Where I work, we have clean room environments, and teach employees about how many particles are allowed in those rooms. We have Class 10, Class 100, Class 1000 and Class 10,000 clean rooms. This means that 10, 100, 1000 and 10,000 particles are allowed in those areas, respectively, per cubic foot of air. These are particles over 0.5 microns in diameter. So guess what is in "normal" outside air? Approximately 50,000 particles per cubic foot of air. Now, add pollution from a diesel engine, and the number becomes truely huge.

John