The properties of atmospheric air change not only with increasing altitude. They are also not the same in different parts of the globe. The hot and dusty air over the Sahara Desert is very different from the frosty and dry air of Antarctica. Usually, the properties of air depend on the geographical latitude and the nature of the surface (land or water), over which it has been for a long time. Large volumes of air with relatively similar properties are called air masses.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.