But the real surprise is that the results point to TFA being formed from short-lived chemical precursors emitted into the atmosphere,” says York University atmospheric chemist Professor Cora Young, senior author of the paper published today. A short-chain per- and polyfluoroalkyl substance (PFAS), TFA forms in the atmosphere when various chemical emissions come together. “TFA is something that we haven't known a lot about before, but we're learning more now that we can measure it,” says York University PhD Candidate Daniel Persaud, the paper’s lead author. We’re finding it at high concentrations in food, for example,” says Young of York Faculty of Science. However, if these performance chemicals for air conditioners are finding their way into the atmosphere, it’s expensive for car manufacturers and consumers for alike.