The search for Revan
Breathable for most species in the galaxy with appropriate levels of Oxygen, Nitrogen and Hydrogen. Usually contains indigenous form of life or plant life.
Breath mask suggested. Usually had a type I atmosphere but it due to some effect the planet lost the effect a Type I has. The planet could sustain some form of indigenous life.
Breath Mask Required. Lack appropriate levels of Oxygen, Nitrogen or sufficient pressure.
To most species breathing a Type III causes immediate impediments or incapacitation. Some species could breath in these atmospheres. Type III sometimes support life forms.
Environment Suit required. Type IV atmospheres are can be toxic, flammable or non-existent.
Type IV atmospheres can cause immediate incapacitation or death to most species.