UV-light sterilization lamps in the airlock
(http://images-en.busytrade.com/55198500/Sell-Ultraviolet-Fluorescent-Lamp.jpg)
For safety of the crew, and to avoid contamining Mars with Earth bacteria,
there should be even a quick and simple sterylization procedure. The best candidate is UV radiation.
UV lamps are used to sterylize entrances at the bio-labs on Earth.
They need to be put from every side (to sterylize every surface of the suit), and they should be stronger on Mars
(becouse potential martian bacteria are used to UV radiation).
UV-lamps glow in blue colore. I think that this should be included inside the airlock.