Laser sniffs out toxic gases from afar: System can ID chemicals in atmosphere from a kilometer away

Scientists have developed a way to sniff out tiny amounts of toxic gases -- a whiff of nerve gas, for example, or a hint of a chemical spill -- from up to one kilometer away. The new remote sensing technology can discriminate one type of gas from another with greater specificity than most -- even in complex mixtures of similar chemicals -- and under normal atmospheric pressure, something that wasn't thought possible before.