Syria has used sarin gas and other chemical weapons against its citizens multiple times in recent years. The U.S. government is worried Syria or others might release poison gas against American troops, or even somewhere in the United States.

Where would the gas spread? How far should people evacuate? A major factor is the local microclimate, said Kiran Bhaganagar of the University of Texas at San Antonio.

“The Army approached us with a very simple problem,” she said. “If someone releases a chemical gas such as sarin, they want us to develop a technology where they know what direction the gas will go in 10 minutes, in an hour, in two hours, so they can plan an evacuation program.

She’s leading a team that is developing a small fleet of unpiloted aerial vehicles (UAVs or drones) to measure wind direction, turbulence, temperature and other important factors in the area near where such a gas has been released, or is suspected to have been released.

They send or bring that information back to a computer running software that can interpret the measurements and predict where the toxic plume will drift. “Then our computer model can tell us in 10 minutes, 20 minutes, one hour, four hours from now over how much area and in which direction did it spread,” said Bhaganagar, an associate professor of mechanical engineering at UTSA specializing in fluid dynamics and turbulence.

She recruited a team with expertise in turbulence, microclimate and drone technology.

“Step one, we have a series of drones to pick up whatever information there is about wind speed, the pollutant, whatever gas was released,” Bhaganagar said. Four or five cooperative UAVs with 20 minutes or so of battery time would be enough, she said.

They’ve completed the computer model and ran a retrospective experiment, plugging in microclimate data from weather sensors in Syria to see if the model would correctly show where a sarin gas plume went in an April, 2017 attack in Khan Sheikhun, Syria, that killed as many as 100 people and injured hundreds of others.

“It was it was released at a time of day when the turbulence was very strong,” she said.  “Another day, another time, it wouldn’t have been so strong. Turbulence makes a huge difference in how far and how fast it was spread. That is why it become a big tragedy.”

Bhaganagar is confident her team will finish the project and deliver it to the U.S. Army. Their research award from the Minority Serving Institutions STEM Research & Development Consortium ran out Feb. 1. “We have finished earlier than promised,” she said. “We had very motivated students who were excited about the project.”

They’re using similar technology in another project funded by MSRDC for the U.S. Coast Guard.

“They want to do a very similar thing but in the ocean when you have a human body or something that is lost,” she said. “We want to see if we can predict which direction it might have drifted.”