Diving with Nitrox vs. Normal Air: What’s the Difference?

Scuba diving opens up a world of underwater adventure, but the type of gas you use can significantly impact your dive experience. Two common choices are nitrox and normal air. Understanding the differences between these gas mixtures can help divers make informed decisions and enhance their underwater excursions. Here’s a look at how nitrox and normal air compare, and what that means for your diving experience.

Normal Air: The Standard Mix

Did you know that our “oxygen” is mostly made up of nitrogen? Our average breathing air and the gas mixture used in recreational scuba diving are incredibly similar, consisting of approximately 78% nitrogen, 21% oxygen, and 1% other gases. For most recreational divers, this normal air is sufficient and provides a reliable standard for exploring underwater environments.

Advantages of Diving with Normal Air:

• Familiarity: Normal air is the default gas for most divers, so there's no need for special training or equipment.
• Widely Available: Air is readily available at most dive shops and fills stations.
• Simple Equipment Requirements: There’s no need for specialized tanks or analysis equipment.

Disadvantages of Diving with Normal Air:

• Nitrogen Narcosis: At deeper depths, nitrogen can cause narcosis, a state of euphoria or impaired judgment.
• Longer Surface Intervals: Divers using normal air might require longer surface intervals between dives to allow for adequate off-gassing of nitrogen.

Nitrox: Enriched Air Diving

Nitrox, or enriched air nitrox (EANx), is a gas mixture that contains a higher percentage of oxygen than normal air, typically between 32% and 40%, with the remainder being nitrogen. The increased oxygen content reduces the proportion of nitrogen, which can influence various aspects of diving.

Advantages of Diving with Nitrox:

• Reduced Nitrogen Absorption: With less nitrogen in the mix, divers absorb less nitrogen during their dive, which can reduce the risk of decompression sickness (DCS) and allow for longer bottom times at recreational depths.
• Shorter Surface Intervals: Nitrox can lead to shorter surface intervals between dives because of reduced nitrogen loading in the body.
• Potential for Longer Dives: Divers may enjoy extended dive times without increasing the risk of nitrogen narcosis.

Disadvantages of Diving with Nitrox:

• Special Training Required: Divers need to complete a nitrox certification course to understand how to use the gas safely and manage the increased oxygen levels.
• Equipment Considerations: Nitrox requires careful analysis and monitoring. Equipment must be compatible with higher oxygen levels to avoid risks of oxygen toxicity or equipment damage.
• Availability: Not all dive shops offer nitrox, and it may come at an additional cost.

Safety and Considerations

When switching from normal air to nitrox, safety is paramount. Here are a few considerations:

• Oxygen Toxicity: Higher oxygen levels increase the risk of oxygen toxicity, especially at depths beyond 30 meters (100 feet). Divers must adhere to recommended depth limits and understand the symptoms of toxicity.
• Gas Analysis: It’s crucial to analyze the nitrox blend before each dive to ensure it matches your planned mix and to avoid accidental exposure to higher-than-intended oxygen levels. We use a Nuvair Oxygen Quickstick Analyzer and inform our nitrox divers of their mixture.
• Dive Planning: Nitrox dives require careful planning, including adjusted no-decompression limits and understanding how to use dive tables or computers specific to nitrox.

Choosing between diving with nitrox or normal air depends on your diving goals and preferences. Nitrox can offer longer bottom times and shorter surface intervals, making it appealing for multi-dive days and deeper dives. However, it requires specialized training and equipment management. Normal air remains a reliable and widely accessible option, suitable for most recreational diving needs.

Whether you opt for nitrox or stick with normal air, both offer unique benefits and challenges. By understanding these differences, divers can better plan their underwater adventures, enhancing both safety and enjoyment.

FAQs

What is the difference between diving with normal air and nitrox?

Normal air is made up of approximately 21% oxygen and 79% nitrogen. Nitrox, on the other hand, is a gas mixture that contains more oxygen, typically between 32% and 36%, with less nitrogen. The primary benefit of diving with nitrox is that the reduced nitrogen levels lower the risk of nitrogen absorption, which can help extend bottom times and reduce decompression stress.

Why should I consider using nitrox instead of regular air?

Divers use nitrox to extend their bottom times at moderate depths, reduce the risk of decompression sickness (DCS), and feel less fatigued after diving. By reducing the amount of nitrogen absorbed into the body, nitrox allows divers to stay underwater longer without exceeding no-decompression limits.

Do I need special training to dive with nitrox?

Yes, you need a nitrox certification to dive with enriched air. This training covers how to safely use nitrox, including understanding oxygen toxicity limits, how to analyze nitrox tanks, and adjusting dive plans to account for the different gas mixtures.

Can I dive deeper with nitrox than with regular air?

No, nitrox is generally not used for deep dives. Although it allows for longer bottom times at moderate depths, the higher oxygen concentration increases the risk of oxygen toxicity at greater depths. Divers need to stay within shallower depth limits when using nitrox, which vary depending on the specific nitrox mix.

Is nitrox safer than normal air?

Nitrox can be safer than normal air for certain dives because it reduces the amount of nitrogen the body absorbs, lowering the risk of decompression sickness. However, it comes with an increased risk of oxygen toxicity if used at depths beyond safe limits. Proper training and understanding of nitrox use are essential for safety.

How do I know what mix of nitrox I am using?

You must analyze the contents of your tank before each dive to know the exact oxygen percentage in the nitrox mix. We use an oxygen analyzer, and it's a requirement for nitrox-certified divers to check their tanks to ensure they plan their dives correctly and avoid risks.

Will I feel less tired after a nitrox dive compared to a dive with normal air?

Some divers report feeling less fatigued after diving with nitrox compared to normal air. This is likely because less nitrogen is absorbed into the body, which may reduce the strain on the body after multiple dives. However, this effect can vary among divers and isn’t guaranteed.