What Makes Up the Air We Breathe: A Diver’s Guide

The air we normally breathe consists primarily of which gases?

• A. Hydrogen and Helium
• B. Nitrogen and Oxygen
• C. Carbon Dioxide and Nitrogen
• D. Oxygen and Argon

Answer: (B)

The air we normally breathe consists primarily of nitrogen and oxygen. In the atmosphere, nitrogen makes up about 78% of the air, while oxygen constitutes approximately 21%. This balance is essential for supporting life on Earth, as oxygen is crucial for respiration in most living organisms. The presence of nitrogen, although it does not participate in respiration, plays a vital role in diluting the oxygen and preventing it from being toxic at higher concentrations. The other gases present in the atmosphere, such as argon, carbon dioxide, and trace gases, are minimal in comparison and do not significantly alter the composition of the air we breathe. Understanding the composition of breathable air is essential for divers, particularly when using different gas mixtures for diving, such as nitrox, which alters this balance to optimize oxygen levels while minimizing the risks associated with higher nitrogen levels.

Let's take a moment to look at something often overlooked: the air we breathe. A seemingly simple concept, but when you're gearing up for a scuba diving adventure, understanding what's in the air becomes crucial. So, what gases make up the atmosphere around us? A quick quiz might help clarify: Do we primarily breathe in hydrogen and helium? Or maybe carbon dioxide and nitrogen? The truth is, the air we normally breathe is made up mainly of nitrogen and oxygen – that’s about 78% nitrogen and 21% oxygen. This simple mixture is vital for life itself.

Now, you might ask, why does the ratio matter, especially for divers? Here’s the thing: while humans need oxygen for respiration, nitrogen serves as a diluting agent keeping oxygen levels in check so they don’t become toxic at higher concentrations. That’s right! Nitrogen doesn’t participate in our respiration, but it plays a key role in maintaining a safe balance in the air that supports life.

When you’re underwater exploring the wonders of the ocean, this balance can shift. Cue nitrox, a gas mixture that modifies this balance to enhance our diving experiences. By increasing the percentage of oxygen and decreasing nitrogen, divers can enjoy longer bottom times while reducing the risks associated with nitrogen narcosis and decompression sickness.

But that’s just the tip of the iceberg. The other gases floating around in our atmosphere aren’t quite as influential. Sure, there’s argon, carbon dioxide, and a sprinkling of trace gases, but their impact on our breath is minimal compared to nitrogen and oxygen. It’s that classic, essential duo we depend on day in and day out.

Understanding these fundamentals of breathable air is not only interesting; it’s pivotal for divers. The dive equipment and gas mixtures we choose can be influenced by this knowledge, allowing us to fine-tune our diving experiences while keeping safety a top priority. After all, who wouldn’t want to savor every moment beneath the waves without the worry of running afoul of nitrogen-related troubles?

As you prepare for your next dive adventure or perhaps even a study session for the Scuba Diving International (SDI) Computer Nitrox Exam, remind yourself of the air that supports your exploration. Getting a grasp of the basic elements of our breathable air opens a window to better diving practices, enabling you to immerse yourself fully in the underwater beauty around you. So, next time you’re out on the boat, taking a deep breath of that fresh air, you’ll know exactly what your lungs are soaking in!