The data "reveals a clear discrepancy between what two major companies claim about their dryers' sound performance and the real-world operating sound levels of their hand dryers," Keegan writes.

Sound that is 120 decibels, just 10 decibels higher than hand dryers, can immediate hurt ears. That's why Nora hopes that her research encourages companies to rethink the dryers.

For each hand dryer, Nora collected 20 measurements, gauging sound from five heights, from two distances and with or without hands present. What she found was striking and straightforward.