Nick said:

"but expect exotic redox chemistry on the exposed surface of every tiny dust grain. That's a lot of surface!"

No doubt about that. It was probably oxidants on Martian bulldust that gave Gil Levin his "15 minutes of fame".

If I was designing an air lock to a Mars spacecraft or colony, I'd include a fine mist water shower. The astronaut would come in from outdoors into the airlock and then pump up to 20 millbar pressure. Then he would spray down under the water shower. Then he'd seal of the water drain and dump the atmosphere back to 6 millibars to dry off the equipment. He'd then repressurize to one bar and get out of his pressure suit.

Gary