What is O2?

O2 is the chemical formula for oxygen. Oxygen is a diatomic molecule, two oxygen atoms bonded together. It makes up about 21% of Earth's atmosphere. Humans and many other organisms need it for cellular respiration. Without it, we can't survive. So in normal conditions, it's vital. Below is the basic information for O2:

1. Oxygen (O₂) Overview

• ​Chemical Composition: Diatomic molecule (two oxygen atoms) essential for aerobic respiration.
• ​Atmospheric Presence: Constitutes ~21% of Earth's atmosphere.
• ​Biological Role: Critical for cellular energy production (ATP synthesis) in humans and most organisms.

2. Health Risks Associated with O₂

• ​Hypoxia (Oxygen Deficiency):

  • ​Causes: Low oxygen environments (e.g., high altitudes, confined spaces).
  • ​Effects: Dizziness, shortness of breath, cognitive impairment, and organ failure.
  • ​At-Risk Groups: Mountaineers, pilots, and individuals in poorly ventilated areas.

• ​Hyperoxia (Oxygen Excess):

  • ​Oxygen Toxicity:
    • ​CNS Toxicity: Seizures, vision changes (common in divers using pure O₂ at depth).
    • ​Pulmonary Toxicity: Lung inflammation and damage from prolonged high-concentration medical O₂.
  • ​Retinopathy of Prematurity: Eye damage in premature infants exposed to high O₂ levels.

• ​Reactive Oxygen Species (ROS):

  • ​Oxidative Stress: Imbalance between ROS (e.g., free radicals) and antioxidants, linked to aging, cancer, and neurodegenerative diseases.
  • ​Contributors: Pollution, smoking, and radiation exacerbate ROS production.

• ​Medical Oxygen Therapy Risks:

  • ​COPD Patients: Excessive O₂ can suppress respiratory drive, leading to hypercapnic respiratory failure.

3. Physical and Safety Hazards

• ​Fire Risk: O₂ supports combustion; high concentrations accelerate fires (e.g., industrial or medical settings).
• ​Liquid Oxygen Hazards: Cryogenic temperatures can cause frostbite upon contact.

4. Key Scenarios

• ​Diving: Pure O₂ use at depth risks CNS toxicity.
• ​Medical Use: Prolonged high-flow O₂ can damage lungs.
• ​Industrial Handling: Proper storage and handling are crucial to prevent accidents.

Conclusion
While O₂ is vital for life, improper levels (too little or too much) pose significant health risks. Context-specific management—such as controlled medical use, safe diving practices, and industrial precautions—is essential to mitigate these risks.