An exhaust treatment system for a combustion source is disclosed. The exhaust treatment system may have a supply of catalyst configured to lower the combustion threshold value of an exhaust constituent, and an injector operable to selectively pass catalyst to the exhaust constituent. The exhaust treatment system may further have a controller in communication with the injector. The controller may be configured to determine a temperature of an exhaust flow, and operate the injector to pass catalyst in response to the combustion threshold value being greater than the determined temperature.