Which one of the following is the correct order in which the gases from the atmosphere disappear as one moves away from the surface of the earth?

The vertical distribution of atmospheric gases is determined by their molecular weight and chemical stability. As one moves away from the Earth's surface, gases disappear or become negligible at different altitudes. According to geographical records, carbon dioxide and water vapour are found only up to a height of approximately 90 km from the surface [2]. Oxygen, while more abundant, becomes almost negligible at a height of about 120 km [2]. Nitrogen, being the most abundant gas in the homosphere (up to 80 km) and relatively stable, persists longer in significant proportions compared to carbon dioxide and oxygen as altitude increases [4]. Therefore, the correct order of disappearance (from lowest altitude limit to highest) is Carbon dioxide, followed by Oxygen, and finally Nitrogen. This sequence reflects the transition from the well-mixed homosphere to the heterosphere where gases settle by molecular weight.

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 7: Composition and Structure of Atmosphere > COMPOSITION OF THE ATMOSPHERE > p. 64
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Permanent Gases of The Atmosphere > p. 272
3. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Permanent Gases of The Atmosphere > p. 271
4. [4] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Dirunion of Atmosphere > p. 7