3M Targets Indoor Air

By Bioscience Staff

From Bioscience World, Autumn 2005

IN THE DEVELOPMENT LAB AT 3M in St. Paul, MN, John Horns, Technical Specialist, developed a test to measure the filter efficiency for fungi of industrial air handlers. The test can help determine indoor air quality in office buildings.

Using the Duo SAS 360 Microbial Air Sampler, he collected air from the upstream and downstream sides inside a fiberglass filter. With a large fan-likeblower, he simulated different air velocities from a minimum of 100 feet per minute to a maximum of 500 feet per minute.

Over a series of days, he collected 20 sample sets. With Malt Extract Agar plates in each head of the Duo SAS, he ran a 500-liter air sample downstream in less than three minutes and a 100-liter air sample upstream in less than thirty seconds. “I chose the Duo SAS 360 Air Sampler because it was straightforward to use and the double heads saved testing time,” he said.

In each sample set, one plate was cultured at 25 degrees C. simulating the temperature outside the body and the other plate was cultured at 37 degrees C. simulating body temperature. “The data of plates was the basis for our efficiency calculations,” Horns said. For example, if the upstream sample is 100 cfu’s. and the downstream sample is 50 cfu’s, the filter efficiency is fifty percent. The test can be used to measure filter efficiency of air handlers used to cool, heat and move air in commercial space.

The Duo SAS 360 Air Sampler

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