Apollo astronauts describe the fresh lunar dirt smell as "spent gunpowder".
Apollo 17's Harrison "Jack" Schmitt, who was one of the 12 astronauts to land on the moon, said that lunar powdery dirt smell was not "metallic or acrid", CBS News reported.
According to Schmitt, he took 7 minutes to come up with the descriptive term of fired gunpowder smell, which was "probably much more implanted" in their memories than other comparable odors.
Larry Taylor, director of the Planetary Geosciences Institute at the University of Tennessee in Knoxville, said that the moonwalkers' mucus membrane sensed highly activated dust particles with 'dangling bonds' on the moon.
Taylor explained that whenever a geologist smashes a rock on Earth, some odor gets generated by the smashing of minerals, thereby dangling bonds gets created, which on moon can exist for a longer time because lunar rock and soil is roughly 43-percent oxygen, most of these unsatisfied bonds are from oxygen.