Sniffing out terrorists
Literally hundreds of people are hurrying through the long airport corridor between Terminals A and B. Among them are two terrorists, who've hidden themselves in the crowd. They're carrying small containers of chemicals in their jacket pockets, individual components for an explosive. But there's something the criminals don't know. As well as being observed by security cameras, they're also being 'sniffed out' by chemical noses hidden in the corridor wall. The smell sensors sound the alarm when the terrorists walk past, alerting an airport security guard who notes the problem on his monitoring equipment. At this point in time, he can't tell precisely who is carrying hazardous chemicals - but he knows the sensor network will continue to 'sniff out' and track down the suspects...