No, an air purifying respirator will NOT save your life in an oxygen deficient atmosphere.
An air PURIFYING respirator removes bad things from air. It does not MAKE good things (like oxygen). In an oxygen deficient atmosphere, you must have a supply of oxygen. This is usually provided by an SCBA, or an air line respirator.
Underground miners have "self rescue breathers." These are a form of respirator that can make oxygen. They are very expensive, have limited uses, and work for a limited time.
The moon has no atmosphere and it is not within the Earth's atmosphere, so it never got "to the atmosphere."
Its transfered by cunduction sun--> atmosphere
Collectively it's called the Atmosphere. There are sub-zones within the atmosphere but collectively it is referred to as the Atmosphere.
To within a milligram - none
The mood
Gravity.
Uneven heating of the Earths atmosphere and oceans by the sun
it decreases
convertion
The Atmosphere
100 100
Ozone layer