Chemical sensors are capable of detecting and analyzing gases in order to alert us to airborn pollutants from industrial processes, smog, natural events such as volcanic eruption and even terrorist activities (hopefully before they occur). These devices can be arranged wherever we require an awareness of what the air is carrying. US embassies use air quality units to release air quality measurements, sometimes in real time - or not at all.
When there is a major event, awareness of risk conditions for first-responder units is key. This week, Popular Science covered a Connecticut fire department using a drone to identify risk conditions for fire fighters at a quarry. While there isn't much new in using remote controlled devices to minimize the risk to human lives - bomb squads and SWAT teams have used robots for some time to get a look at situations before sending in humans - the drone provided a very different look from the air.