Atmosphere types

Type I:
Breathable for most species in the galaxy with appropriate levels of Oxygen, Nitrogen and Hydrogen. Usually contains indigenous form of life or plant life.

Type II:
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.

Type III:
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.

Type IV:
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.

Atmosphere types

The search for Revan Eseke