What percentage of the Earth's atmosphere does argon constitute?

Argon constitutes approximately 1% of Earth's atmosphere. This inert gas is the third most prevalent gas in the atmosphere, following nitrogen and oxygen. The presence of argon in the atmosphere is largely due to its noble gas characteristics, which means it does not readily react with other elements or compounds, allowing it to remain abundant and stable.

Understanding the composition of Earth’s atmosphere and the role of argon is important in various fields, including welding. In Gas Tungsten Arc Welding (GTAW), argon is often used as a shielding gas due to its inert properties, preventing oxidation and contamination of the weld pool. Knowing that argon makes up about 1% of the atmosphere highlights its abundance and relevancy in applications beyond just its natural atmospheric occurrence.