GAINESVILLE --- University of Florida researchers have found a possible solution to a problem that has plagued air pollution control efforts for years: how to control smog-causing emissions from small sources ranging from industrial boilers to lawn mowers.
UF environmental engineering doctoral student Max Lee's findings could lead to new technology for reducing pollution in smog-ridden U.S. cities as well as in developing countries, where cheap, effective pollution controls are desperately needed.
"Everything for small sources currently is very, very expensive," said Eric Allen, professor emeritus of environmental engineering sciences and the chair of Lee's dissertation committee. "The importance of this technique is that it is oriented to the control of small sources and it is economical."
Lee, whose research was sponsored by the U.S. Air Force, said conventional pollution control techniques involve injecting a "reducing" gas into exhaust gas to convert nitrogen oxides, pollutants that are the primary ingredient in smog, to inert gasses.
Because the reducing and exhaust gases must be mixed in precise proportions at specific temperatures, the success of the technique requires emissions to be relatively constant. While this occurs with large emission sources such as coal- or natural gas-burning power plants, smaller sources such as boilers and small engines are operated intermittently and at varying capacity, meaning their emissions vary greatly. Additionally, the design and equipment costs for the reducing gas technology are extremely high.
Seeking a better method, Lee released known concentrations of nitrogen oxides through pellets of alumina, a common material found in many everyday items, coated with a special absorbent material. By measuring resulting emissions, he determined that the coated alumina removed 95 percent of the nitrogen oxides under conditions similar to combustion exhaust.