Does regolith mean any threat for people visting the Moon or the Mars?
If yes, what is that?
Space Exploration Stack Exchange is a question and answer site for spacecraft operators, scientists, engineers, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
Firstly, the Lunar and Martian regolith will be quite different in composition.
Wikipedia has a short list of the harmful effects of Lunar dust, these have been added to, to include potential harmful effects of Martian dust.
Darkening of surfaces, leading to a considerable increase in radiative heat transfer
Abrasive nature of the dust particles may rub and wear down surfaces through friction
Negative effect on coatings used on gaskets to seal equipment from space, optical lenses that include solar panels and windows as well as wiring
Possible damage to astronaut's lungs, nervous, and cardiovascular systems
it can short circuit equipment since some of it is metallic dust
wedge into small openings or spacesuit fabric or stick to it magnetically and cause triboelectric (rubbing) and/or surface photoelectric discharge
contain dangerous chemicals like e.g. calcium perchlorate salts on Mars
it can cover "traps" on untraversed lands, such as dry ice fans, other volatiles, ravines, cracked lava tubes
Cause substantial surface temperature differential
airborne dust can cause electric storms
As for the Martian soil there is a whole host of articles discussing this topic, for example:
Or for how I found this paper: Google Scholar.
One difference between the Martian and Lunar regolith is the degree to which is it moved. Mars has an atmospheric pressure of around 600 Pa, where as the moon is much lower at 0.3 nPa (0.3*10-9 Pa) - that's about 2 thousand billion times lower. So you could logically expect the Martian atmosphere to carry a much larger amount of regolith in dust storms - creating a large issue when looking at regolith covering sensors etc.
EDITED to add notes from TidalWave.