Abstract: A pollutant-controlling combustor assembly for use with a fuel-burning room heater includes at least two combustors through which gaseous combustion products are routed before being discharged into the atmosphere. Each combustor has a downstream side through which combustion products exit the combustor, and the combustors are arranged so that the downstream side of each combustor is fully exposed to the downstream side of every other combustor in the assembly. In addition, the downstream sides of the combustors are positioned about a common space so that combustion products which exit the downstream sides of the combustors enter the common space.