A single atom can make a big difference in the way a molecule works – so can its location. The daily air we breathe has two oxygen atoms (O2) in it. Ozone is a gas consisting of three oxygen atoms (O3). And while we need oxygen to survive, ozone can either help us or hurt us – depending on where it is.

What is the difference between useful and harmful ozone?

Ozone can be beneficial or harmful to your health and the environment, depending on its location in the atmosphere. Helpful ozone is found naturally high above the earth’s surface and protects us from the sun’s ultraviolet rays (radiation). Man-made air pollutants damage the useful ozone.

Harmful ozone is close to the ground. It comes from human activities that release chemicals into the air that react with sunlight to create ground-level ozone.

How can ozone affect my health?

When man-made air pollutants destroy useful ozone, people can receive too much ultraviolet radiation. This can cause:

• Cataracts (clouding of the lens of the eye, leading to poor vision)
• Problem with the immune system (the system that fights disease)
• Skin cancer

Too much ultraviolet radiation can also damage crops (plants we grow for food) and other plants.

Contact with harmful ozone can cause:

• Cough
• Irritated throat
• Worsening of respiratory disorders, such as asthma and bronchitis

Regular exposure to ozone can also cause permanent damage to the lungs, especially in children because their lungs are still developing.