Most people recognize the ozone layer as a part of the Earth’s upper atmosphere that absorbs a sizeable chunk of the sun’s ultraviolet radiation. It has high concentrations of ozone compared to other parts of the atmosphere.

The ozone layer has about 10 parts per million of ozone which is much more than the average of 0.3 parts per million for the entire atmosphere. The layer is found in the lower parts of the upper atmosphere, better known as the stratosphere.

However, ozone gas is present in trace amounts in other parts of the atmosphere. Although the ozone layer shields the Earth from harmful ultraviolet rays from the sun, a high concentration of ozone gas in the lower atmosphere contributes to pollution.

Ozone Gas and Smog

Ground level ozone affects visibility by forming smog. Ozone at ground level is formed by chemical reactions between volatile organic compounds and oxides of nitrogen. It happens when pollutants emitted by chemical plants, refineries, industrial boilers, power plants, and motor vehicles and other sources react in sunlight. That is why ozone is likely to reach high levels on sunny mornings in urban environments and form smog. The smog causes a drop in visibility.

Effect of Ozone on Human Health

Prolonged exposure to ozone may be harmful to human health. The health risk is even greater in older adults, children, people with asthma and people with reduced intake of vitamins E and C. Breathing ozone can trigger a series of health complications including airway inflammation, throat irritation, coughing, chest pain and impaired lung function. Inhalation of ozone-rich air may worsen asthma, emphysema, and bronchitis.

Effect of Ozone on the Environment

Ozone has harmful effects on the environment. It damages ecosystems and vegetation by reducing the ability of plants to open microscopic pores. This reduces the plant’s carbon dioxide intake which affects the photosynthesis process adversely. Consequently, this reduces the commercial forest and agricultural crop yield, increases the susceptibility of plants to pests, diseases, and harsh weather.


The ozone layer is mostly contained in the upper part of the atmosphere and is vitally essential to life on Earth. However, when the concentration of ozone increases at ground level, it negatively affects the lives of humans and degrades the environment as a whole. In other words, ozone in the upper atmosphere is very useful because it prevents harmful radiation from reaching the Earth’s surface. However, ozone in the lower atmosphere may contribute to environmental degradation.