I recall an article from a long time ago that basically said “astronauts report” the moon smells like spent gunpowder and outer space smell like… I think it was ozone.
What they were actually reporting was the smell of the airlocks after they returned from their excursions. The moon has no atmosphere, so it has been accumulating dust from billions of years of asteroid impacts that have never come in contact with oxygen. Many of the chemicals in the dust are oxidative and so when it is exposed to air for the first time it rapidly oxidizes just like gunpowder!
And I think the outer space report was from space walks, and the explanation was that the first time the airlock itself was exposed to hard vacuum, the surfaces of the airlock would have a reaction that left a scent of ozone.
the detail that kills me is moon dust has never contacted oxygen in billions of years, so every time an astronaut came back inside they were essentially doing a chemistry experiment for the first time. the whole moon is just waiting to react with air
At least some ISS astronauts describe smelling burnt metal after returning from EVA, if memory serves. (Others may smell ozone, I've just always remembered hearing burnt metal).
My UV sterilizing lights make my room smell like O3 Ozone and that smells nothing like spent gun-powder to me. The only other time I have smelled the same thing is when there has been mass lightening events in the sky. Were they talking about actual black powder or nitrocellulose? I've smelled black powder at the range when people bring out their antique rifles and that also does not smell like Ozone to me.
There was some concern when Apollo 11 landed that when they repressurized the LEM with moon dust samples inside it would start a fire. I think they had a small test article that they blew a small stream of oxygen over to ensure it wouldn't auto-ignite.