A year or so ago, some guys at NASA developed a chemical sensor that would go in yer iPhone and be able to pick up airborne chemical make up. As usual the reasoning put forward were to do with chemical attacks, so that if there was such a thing to happen, the data from cellphones in the area could be used to determine where exactly the chemical was spreading and how fast.I can't imagine iPhone buyers ticking the box in the Apple Store that puts themselves down as a willing sacrifice to the Anthrax Apocalypse in return for a reduction on their monthly tariff, but it shows proof of concept of the miniturisation of the technology that would enable us to make the technology mobile.