Fog has been billowing inside a small greenhouse on the University of Washington campus for the past month, but it doesn’t arrive on little cat feet. It comes hissing out of high-pressure nozzles.
The man-made mist is part of an effort to help slum-dwellers in Peru harvest moisture from the air. With a small grant from the Environmental Protection Agency, UW students and professors are building and testing fog catchers — and hoping to reel in a bigger grant to mount a full-scale operation in Lima.
“It’s like a cold sauna in here,” UW ecologist and civil engineer Susan Bolton said last week, ducking into the plastic “hoop house,” where industrial-grade misters spewed out a cloud of fine water droplets.
A noisy exhaust fan drew the cloud through a drape of black plastic netting. Droplets settled out on the mesh, coalesced and trickled into a plastic bucket. Forty-five minutes into the morning’s first test run, Bolton and graduate student Peter Cromwell emptied the bucket into graduated cylinders to measure the haul: 1,212 milliliters, or about a third of a gallon.