From the article:
Conventional air-emission-control systems attack the problem at the smokestack with filters and scrubbers. ClearSign Combustion Corp. aims its emission-control technology at a much earlier point in the process, where those emissions are first created: at the flame.
The Tukwila company is developing two approaches to reducing pollutants by controlling the flame used in industrial boilers, kilns, furnaces and turbines. One is electrodynamic combustion control (ECC), which uses electromagnetic fields to control the shape of a flame in a boiler, kiln, furnace or turbine. ECC technology has shown reductions in visible particulate matter of more than 90 percent.