When a public building catches fire, its built-in systems automatically respond: Smoke alarms blare, sprinklers kick on, and occupants quickly evacuate.

But what if the life-threatening danger isn’t fire but invisible airborne contaminants that can make occupants sick? Could a similar smart-building system monitor and improve the quality of the air indoors, where Americans spend 90 percent of their time?

With a contract for up to $40 million from the Advanced Research Projects Agency for Health (ARPA-H), an ambitious multi-institutional research team led by Virginia Tech and including researchers at the University of California, Davis, aims to create just such a system.