The emission of atomic deuterium from decomposing palladium deuteride (PdHx) was studied. The desorption of D atoms and D-2 molecules was confirmed during PdHx decomposition over a temperature range of 190-298 K. It was found that preadsorption of methane at 298 K onto a thin Pd film surface before transformation into palladium deuteride completely precluded emission of D atoms from the obtained PdDx. However preadsorption of oxygen and its reaction products with hydrogen (e.g., OHad or H2Oad) very slightly hindered D atom emission from decomposing PdDx.