Question: What is Smog?
Answer: What we typically call smog today is a mixture of air pollutants—nitrogen oxides and volatile organic compounds—that combine with sunlight to form ozone.
Ozone can be beneficial or harmful, good or bad, depending on its location. Ozone in the stratosphere, high above the Earth, acts as a barrier that protects human health and the environment from excessive amounts of solar radiation. On the other hand, ground-level ozone, trapped near the ground by heat inversions or other weather conditions, is what causes the respiratory distress and burning eyes associated with smog.
Smog: Frequently Asked Questions
