Now, the researchers have identified alternatives to these pieces of the testing apparatus which are around a quarter of the cost of commercial equipment and are readily available from many retailers, including Amazon.
To diffuse the solution, the researchers tested an aroma diffuser, humidifier, mist maker and spray bottle. For the enclosure, they tested a plastic bag, testing hood, a clear storage cube and no enclosure. Testers first underwent quantitative fit-testing to assess the fit on their faces before the qualitative methods. Quantitative testing measures the number of particles inside and outside the mask and is highly accurate. However, it is also time-consuming and expensive, which is why qualitative testing is more frequently used in healthcare settings.
Using an N95 mask from 3M and a KN95 mask from a Chinese manufacturer, the testers then assessed the alternative devices and enclosures. A solution of sodium saccharin—an artificial sweetener—was aerosolised for 60 seconds at a time, and testers were asked whether they could taste the sweetener or not. The test was then repeated with the tester causing an intentional gap in the fit by placing the tip of a finger between the mask and their face.
They found that the combination of an aroma diffuser and a small container, such as a large plastic bag, provided the most accurate and most sensitive setup, with results comparable to commercial qualitative fit-testing solutions.
