Abstract: A method and apparatus for reducing nitrogen dioxide (NO.sub.2) emissions in a dry sodium scrubbing process without significantly reducing sulfur dioxide (SO.sub.2) and nitrogen oxides (NO.sub.x) removal efficiencies. A sodium additive is injected into a flue gas duct carrying flue gas from a combustor to a particulate collection device to remove sulfur dioxide and nitrogen oxides from the flue gas. The flue gas is humidified by introducing water into the flue gas duct at a point upstream of the sodium additive introduction point. Through control of the moisture content of the flue gas and the temperature in the particulate collection device, the amount of NO.sub.2 emissions is reduced to a value below that which causes the creation of a brown plume emanating from the gas stack.