Investigation of fine particle emissions from B-52 aircraft

Emissions from the B-52 aircraft exhibited a single mode distribution that shifted from ∼47nm at the idle engine setting to ∼81 nm at the higher normal engine setting. There was no evidence of ultra-small particles in the nominal range less than 25nm indicating the lack of formation of secondary particles at the engine exhaust plane. The dispersion of the size distribution was relatively constant at approximately 1.92 for the different engine power settings while the total number concentration of particles increased with increasing engine setting. Particles emitted at the two lowest engine settings exhibited greater production of volatile material as evidenced by the reduction of the particle number concentration for the exhaust stream that flowed through the thermodenuder at idle and idle descent. Engine settings at a higher percentage of maximum thrust produced a lower percentage of volatile material and a greater percentage of non-volatile particulate matter. These results are consistent with previous studies and have implications for environmental impact issues near airports since aircraft operate at reduced engine power while taxiing and maneuvering in airports.