To help astronauts survive long-term missions, NASA started thinking about ways to grow food in space. This required reducing the amount of ethylene in the air. Ethylene is a gas released by plants, and its build-up in a closed environment (like the space station) leads to wilting and accelerated plant decay. NASA funded research at the University of Wisconsin Madison to work on this problem. It turns out that the system the researchers developed to remove ethylene from the air can also be used to remove other organic particles, making it the basis for an air purifier. The technology was licensed by a private company, and is now used to build home and commercial air purifiers.
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