Auiris

Air is scientifically classified as a mixture because its constituent gases, such as nitrogen (78%), oxygen (21%), argon, and carbon dioxide, are physically combined rather than chemically bonded [1]. Unlike a compound, which has a fixed chemical ratio and distinct properties, the components of air retain their individual chemical identities and can be separated through physical processes like fractional distillation. The composition of air is not constant; it varies based on factors such as altitude, humidity, and environmental conditions. While industrial zones may contain higher concentrations of pollutants like sulfur dioxide or particulate matter, and pollution-free zones may have fewer trace contaminants, the fundamental nature of air remains a mixture in both scenarios [2]. Therefore, air is always a mixture regardless of the specific proportions of its components or the presence of localized pollutants.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 8: Nature of Matter: Elements, Compounds, and Mixtures > 8.1.1 Is air a mixture? > p. 118
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > 20.1. Composition of The Earth's Atmosphere > p. 270