When operating properly, the monitors constantly sample the air and send data to EPA headquarters, where computers monitor the data and alert officials to unusual readings.
The school is in the process of patenting a process in which dogs would sample the air left in the wake of travelers passing through an airport terminal.
In Texas, if you get a second offense DWI you have to install and maintain a deep lung air device on the car that requires a breath sample before it will allow you to start your car.