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UD Wind Tunnel Helps Agrabusiness Contain Pesticides

Mar 18, 2019

Researchers at the University of Dayton are helping the farming business figure out how to prevent spray drift, or the unintentional use of pesticides outside the target area. March 6, UD unveiled an EPA-approved low-speed wind tunnel, believed to be just the second on a U.S. college campus to hold that designation.

UD Assistant Professor of Mechanical and Aeronautical Engineering Siddard Gunasekaran says the tunnel will help avoid what could be a several month-long wait for the EPA approved test.

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 researchers spray test samples from agricultural companies through a laser to measure the range of droplet sizes. Anything smaller than a human hair doesn't have enough weight to overcome air resistance and tends to float in wind currents. This is known as spray drift.  

Gunasekaran is able to tell what combinations of chemicals and spray nozzles work to prevent spray drift.

Chemicals go into the wind tunnel and are captured by scrubbers so no droplets escape the testing area.
Credit Ann Thompson / WVXU

Agronomist John Smith works for Winfield United, a company that sells pesticides and other products. "It's obviously a very important topic as we go forward and our chemistry methods get better to detect low levels of pesticides in the environment," he says. 

Zari Dobrev's company TeeJet Technologies makes spray nozzles. It is often difficult to convince the farmer to spend money to replace the nozzles.

"One way it's being handled right now is some of the chemical manufacturers - the people that actually produce the chemicals being sprayed - on their labels, they'll actually call out what size droplet has to be used," Dobrev says. 

Some nozzles cost $20-30 each and there are machines that call for 80-90 nozzles.

Some spray tests take a few hours. Others take a few days.