Scientists at NASA's Ames Research Center have developed a prototype device designed to plug into an iPhone, for the purpose of detecting harmful chemicals in the air. The gadget, which will be retrofitted for other smart phones, contains sensors for sniffing ammonia, chloride, hydrazine, formaldehyde and other potentially harmful substances. The long-term goal is to turn cell phone users into a vast threat detection network.

Guest: Jing Li, NASA