You are correct! Hydrogen gas is not one of the main constituents of air.

Here's why:

* Air Composition: Air is primarily composed of nitrogen (78%), oxygen (21%), and a small percentage of argon (0.9%). Other gases, like carbon dioxide, neon, helium, and methane, make up only trace amounts.

* Hydrogen's Abundance: While hydrogen is the most abundant element in the universe, it is relatively rare in Earth's atmosphere. This is because hydrogen is very light and escapes Earth's gravity.

* Trace Amounts: There are trace amounts of hydrogen gas in the atmosphere, but it's not a significant component.

Let me know if you have any other questions!