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U.S. EPA to Accept Test Results from University of Dayton Wind Tunnel

The U.S. Environmental Protection Agency will accept and review results from spray drift experiments in the University of Dayton Low-Speed Wind Tunnel. University of Dayton assistant professor of mechanical and aeronautical engineering Sidaard Gunasekaran and his industry partner Kyle Butz, a technical adviser with Spray Analytics, believe the facility is just the second on a U.S. college campus to hold this designation.

Having the UD tunnel open for testing will help alleviate what can be a several-month backlog of agricultural and spray nozzle companies who must put their products through this testing to be approved for use in the field, according to Gunasekaran. The other university facility is at the University of Nebraska.

"With our facility, clients can test nozzle, pressure and tank mixture for applying treatments, and use the data to accurately predict the drift potential in the field," Gunasekaran said.

During testing, the wind tunnel is set to 15 miles per hour and the sprayer is set to the EPA-approved pressure for the mixture and nozzle being tested. Then, the duo sprays test samples from agricultural companies through a laser to measure the range of droplet sizes. The droplet size information is then used to understand the drift potential of each test combination.

"There are chemical, fluid and nozzle properties, plus spray pressure, that factor into spray efficiency," Butz said. "There have been lawsuits from drift claims. If I spray for a certain weed, and my neighbor's crop is not resistant to that, I can cause damage to them, and it becomes a civil issue.

"If we can optimize the way farmers spray, we should be able to keep the active spray on target. That way, the farmer is happy because he's maximizing coverage of their crop. And the neighbors are happy because they are not being impacted at all."

The pair will show off the wind tunnel to nozzle and chemical manufacturing companies plus government agencies March 12 during a free, public spray drift seminar and open house and March 13 during a droplet size testing course facilitated by Butz. The course costs $795.

"This is an opportunity for everyone to get together to discuss concerns and research in this area, and how we can best address spray drift," Gunasekaran said. "The seminar's goal is to focus on current research techniques and requirements for testing and how to better disseminate information from the EPA to farmers."

For more information on or to register for both events, visit

For more information or interviews, contact Shawn Robinson, associate director of news and communications, at 937-229-3391 or


News and Communications Staff