The by-products of burning coal aren't pleasant: apart from the greenhouse gas carbon dioxide and its next of kin, carbon monoxide, fly ash in the exhaust contains trace metals such as arsenic that are hazardous to human health if inhaled. Conventional filters used in coal-fired power plants and other industrial smokestacks employ steel plates, called electrostatic precipitators, to attract dust particles and keep them from escaping into the atmosphere. But researchers from Ohio University have now improved on that technology.

Indeed, Hajrudin Pasic, Khairul Alam and David Bayless recently patented a new type of membranewoven from carbon, silicon and other fibers and measuring only one to three millimeters thickthat captures fine air pollutants and heavy metals more cheaply and efficiently than conventional filters. "The membranes are better suited for meeting the newest Environmental Protection Agency (EPA) environmental regulations, which are aimed at small particles," Pasic says. "The particles otherwise can't be efficiently treated by conventional electrostatic precipitators that use steel plates." What's more, the researchers say that plants can retrofit existing filters with the new membranes, which are easier to maintain. Not only are the membranes considerably lighter, they can also be washed in water and won't rust.