Io, whose interior is constantly heated by strong gravitational tidal forces, is the most volcanically-active body in our Solar System. The Moon has a tenuous atmosphere composed primarily of sulfur dioxide (SO2), which comes from eruptions of its many volcanoes and sublimation of its SO2 from surface frost.
Scientists have used ALMA to study the trace gases of sodium chloride (NaCl – table salt) and potassium chloride (KCl) in the atmosphere. They found that these compounds are largely confined and at high temperatures, indicating that they too are expelled by volcanoes.
They also found that they are at different locations from where SO2 is emitted, which suggests that there may be differences in the subsurface magma or eruptive process between volcanoes that emit SO2 and those that produce NaCl and KCl. emit.