PADI ENRICHED AIR DIVER COMPLETE EXAM QUESTIONS
AND 100% VERIFIED ANSWERS LATEST VERSION (PASS
GUARANTEE)
1. Q: What is enriched air nitrox? ANSWER Enriched air nitrox (EAN)
is breathing gas that contains more than 21% oxygen and less than 79%
nitrogen.
2. Q: What is the primary benefit of diving with enriched air?
ANSWER Reduced nitrogen absorption, allowing for longer no-
decompression limits or shorter surface intervals.
3. Q: What are the two most common enriched air blends? ANSWER
EAN32 (32% oxygen) and EAN36 (36% oxygen).
4. Q: What does EAN32 mean? ANSWER Enriched Air Nitrox with 32%
oxygen and 68% nitrogen.
5. Q: What does EAN36 mean? ANSWER Enriched Air Nitrox with 36%
oxygen and 64% nitrogen.
6. Q: Does enriched air allow you to dive deeper than with regular air?
ANSWER No, enriched air actually has shallower maximum depth limits
due to oxygen toxicity concerns.
7. Q: What is the main reason divers use enriched air? ANSWER To
extend bottom time and reduce nitrogen loading.
8. Q: Can you feel the difference breathing enriched air underwater?
ANSWER No, you cannot feel any difference breathing enriched air
compared to regular air.
9. Q: Is enriched air safer than regular air? ANSWER It can reduce
decompression sickness risk when used properly, but introduces oxygen
toxicity risks if misused.
, 10.Q: What percentage of oxygen is in regular air? ANSWER
Approximately 21% oxygen.
Section 2: Oxygen Exposure and Toxicity
11.Q: What is oxygen toxicity? ANSWER A harmful condition caused by
breathing oxygen at high partial pressures for extended periods.
12.Q: What are the two types of oxygen toxicity? ANSWER Central
Nervous System (CNS) toxicity and pulmonary (whole body) oxygen
toxicity.
13.Q: What is CNS oxygen toxicity? ANSWER Toxicity affecting the
central nervous system, which can occur rapidly at high oxygen partial
pressures.
14.Q: What is the acronym for CNS oxygen toxicity symptoms?
ANSWER VENTID-C or ConVENTID.
15.Q: What does VENTID stand for? ANSWER Vision problems, Ear
ringing, Nausea, Twitching, Irritability, Dizziness.
16.Q: What does the 'C' in VENTID-C stand for? ANSWER
Convulsions.
17.Q: What is the most serious symptom of CNS oxygen toxicity?
ANSWER Convulsions (seizures), which can be fatal underwater.
18.Q: At what partial pressure does CNS oxygen toxicity become a
concern? ANSWER Generally above 1.4 ATA, with 1.6 ATA being the
maximum recreational limit.
19.Q: What is pulmonary oxygen toxicity? ANSWER Lung irritation and
damage from prolonged exposure to elevated oxygen levels.
20.Q: How long does it take for pulmonary oxygen toxicity to develop?
ANSWER Many hours to days of continuous exposure to elevated
oxygen levels.
21.Q: What are symptoms of pulmonary oxygen toxicity? ANSWER
Burning sensation in the chest, coughing, difficulty breathing, and
reduced vital capacity.
22.Q: What is the maximum partial pressure of oxygen (PO2) for
recreational enriched air diving? ANSWER 1.4 ATA for normal
diving, with 1.6 ATA as a contingency maximum.
, 23.Q: What is partial pressure? ANSWER The pressure exerted by a
single gas in a mixture of gases.
24.Q: How do you calculate partial pressure of oxygen? ANSWER
Multiply the fraction of oxygen (as a decimal) by the absolute pressure in
atmospheres.
25.Q: What is the formula for calculating oxygen partial pressure?
ANSWER PO2 = FO2 × Absolute Pressure (in ATA).
26.Q: If diving EAN32 at 30 meters/100 feet, what is the oxygen partial
pressure? ANSWER 1.28 ATA (0.32 × 4.0 ATA = 1.28).
27.Q: What is the oxygen partial pressure breathing air at 40
meters/130 feet? ANSWER 1.05 ATA (0.21 × 5.0 ATA = 1.05).
28.Q: Why is oxygen toxicity depth-dependent? ANSWER Because
partial pressure increases with depth, making the oxygen concentration
effectively higher.
29.Q: Can oxygen toxicity occur at the surface? ANSWER Yes, but only
after many hours of breathing high concentrations of oxygen.
30.Q: What should you do if you experience symptoms of oxygen
toxicity? ANSWER Ascend immediately to a shallower depth to reduce
the oxygen partial pressure.
Section 3: Maximum Operating Depth (MOD)
31.Q: What is Maximum Operating Depth (MOD)? ANSWER The
deepest depth you can dive with a specific nitrox mix while staying
within oxygen exposure limits.
32.Q: How is MOD calculated? ANSWER MOD (in meters) =
((Maximum PO2 ÷ Oxygen fraction) - 1) × 10.
33.Q: What is the MOD for EAN32 using a maximum PO2 of 1.4?
ANSWER 34 meters/111 feet.
34.Q: What is the MOD for EAN36 using a maximum PO2 of 1.4?
ANSWER 29 meters/95 feet.
35.Q: What happens if you exceed the MOD? ANSWER You risk
oxygen toxicity, particularly CNS oxygen toxicity.
36.Q: Should you dive to your MOD on every dive? ANSWER No,
MOD is a maximum limit; it's safer to stay well within it.
AND 100% VERIFIED ANSWERS LATEST VERSION (PASS
GUARANTEE)
1. Q: What is enriched air nitrox? ANSWER Enriched air nitrox (EAN)
is breathing gas that contains more than 21% oxygen and less than 79%
nitrogen.
2. Q: What is the primary benefit of diving with enriched air?
ANSWER Reduced nitrogen absorption, allowing for longer no-
decompression limits or shorter surface intervals.
3. Q: What are the two most common enriched air blends? ANSWER
EAN32 (32% oxygen) and EAN36 (36% oxygen).
4. Q: What does EAN32 mean? ANSWER Enriched Air Nitrox with 32%
oxygen and 68% nitrogen.
5. Q: What does EAN36 mean? ANSWER Enriched Air Nitrox with 36%
oxygen and 64% nitrogen.
6. Q: Does enriched air allow you to dive deeper than with regular air?
ANSWER No, enriched air actually has shallower maximum depth limits
due to oxygen toxicity concerns.
7. Q: What is the main reason divers use enriched air? ANSWER To
extend bottom time and reduce nitrogen loading.
8. Q: Can you feel the difference breathing enriched air underwater?
ANSWER No, you cannot feel any difference breathing enriched air
compared to regular air.
9. Q: Is enriched air safer than regular air? ANSWER It can reduce
decompression sickness risk when used properly, but introduces oxygen
toxicity risks if misused.
, 10.Q: What percentage of oxygen is in regular air? ANSWER
Approximately 21% oxygen.
Section 2: Oxygen Exposure and Toxicity
11.Q: What is oxygen toxicity? ANSWER A harmful condition caused by
breathing oxygen at high partial pressures for extended periods.
12.Q: What are the two types of oxygen toxicity? ANSWER Central
Nervous System (CNS) toxicity and pulmonary (whole body) oxygen
toxicity.
13.Q: What is CNS oxygen toxicity? ANSWER Toxicity affecting the
central nervous system, which can occur rapidly at high oxygen partial
pressures.
14.Q: What is the acronym for CNS oxygen toxicity symptoms?
ANSWER VENTID-C or ConVENTID.
15.Q: What does VENTID stand for? ANSWER Vision problems, Ear
ringing, Nausea, Twitching, Irritability, Dizziness.
16.Q: What does the 'C' in VENTID-C stand for? ANSWER
Convulsions.
17.Q: What is the most serious symptom of CNS oxygen toxicity?
ANSWER Convulsions (seizures), which can be fatal underwater.
18.Q: At what partial pressure does CNS oxygen toxicity become a
concern? ANSWER Generally above 1.4 ATA, with 1.6 ATA being the
maximum recreational limit.
19.Q: What is pulmonary oxygen toxicity? ANSWER Lung irritation and
damage from prolonged exposure to elevated oxygen levels.
20.Q: How long does it take for pulmonary oxygen toxicity to develop?
ANSWER Many hours to days of continuous exposure to elevated
oxygen levels.
21.Q: What are symptoms of pulmonary oxygen toxicity? ANSWER
Burning sensation in the chest, coughing, difficulty breathing, and
reduced vital capacity.
22.Q: What is the maximum partial pressure of oxygen (PO2) for
recreational enriched air diving? ANSWER 1.4 ATA for normal
diving, with 1.6 ATA as a contingency maximum.
, 23.Q: What is partial pressure? ANSWER The pressure exerted by a
single gas in a mixture of gases.
24.Q: How do you calculate partial pressure of oxygen? ANSWER
Multiply the fraction of oxygen (as a decimal) by the absolute pressure in
atmospheres.
25.Q: What is the formula for calculating oxygen partial pressure?
ANSWER PO2 = FO2 × Absolute Pressure (in ATA).
26.Q: If diving EAN32 at 30 meters/100 feet, what is the oxygen partial
pressure? ANSWER 1.28 ATA (0.32 × 4.0 ATA = 1.28).
27.Q: What is the oxygen partial pressure breathing air at 40
meters/130 feet? ANSWER 1.05 ATA (0.21 × 5.0 ATA = 1.05).
28.Q: Why is oxygen toxicity depth-dependent? ANSWER Because
partial pressure increases with depth, making the oxygen concentration
effectively higher.
29.Q: Can oxygen toxicity occur at the surface? ANSWER Yes, but only
after many hours of breathing high concentrations of oxygen.
30.Q: What should you do if you experience symptoms of oxygen
toxicity? ANSWER Ascend immediately to a shallower depth to reduce
the oxygen partial pressure.
Section 3: Maximum Operating Depth (MOD)
31.Q: What is Maximum Operating Depth (MOD)? ANSWER The
deepest depth you can dive with a specific nitrox mix while staying
within oxygen exposure limits.
32.Q: How is MOD calculated? ANSWER MOD (in meters) =
((Maximum PO2 ÷ Oxygen fraction) - 1) × 10.
33.Q: What is the MOD for EAN32 using a maximum PO2 of 1.4?
ANSWER 34 meters/111 feet.
34.Q: What is the MOD for EAN36 using a maximum PO2 of 1.4?
ANSWER 29 meters/95 feet.
35.Q: What happens if you exceed the MOD? ANSWER You risk
oxygen toxicity, particularly CNS oxygen toxicity.
36.Q: Should you dive to your MOD on every dive? ANSWER No,
MOD is a maximum limit; it's safer to stay well within it.
