Effects of Ground Level Ozone

Human Health Effects

Image of a healthy lung airway Image of an inflamed lung airway
Ozone can inflame the lung’s lining. These photos show a healthy lung air way (left) and an inflamed lung air way (right). Photos courtesy of EPA.

Breathing ground-level ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion.  It can worsen bronchitis, emphysema, and asthma. Ozone also can reduce lung function and inflame the lining of the lungs. Repeated exposure may permanently scar lung tissue.

Healthy people also experience difficulty breathing when exposed to ozone pollution. Because ozone forms in hot weather, anyone who spends time outdoors in the summer may be affected, particularly children, outdoor workers and people exercising. Some people who   don't fall into any of these categories may also find themselves sensitive to ozone.

For detailed information about how ozone affects human health, go to EPA's "Health Effects of Ozone in the General Population" web page.

Ozone can reduce lung function, making it more difficult to breathe deeply and quickly. Those with lung diseases, children, outdoor   workers, and those who exercise outdoors should reduce activity levels or stay indoors when ozone levels are elevated.

Environmental Effects

Signs of ozone damage include flecking, stippling, bronzing and reddening on plant leaves. Photo courtesy of USDA

Ozone damages vegetation and ecosystems by inhibiting the ability of plants to open the microscopic pores on their leaves to breathe. It interferes with the photosynthesis process by reducing the amount of carbon dioxide the plants can process and release as oxygen.

Elevated levels of ozone leads to reduced agricultural crop and commercial forest yields, reduced growth and survivability of tree seedlings, and increased susceptibility to diseases, pests and other stresses such as harsh weather.

Yield Loss Caused by Ozone

Dicot species, such a soybean, cotton and peanut, are more sensitive to yield loss caused by ozone than monocot species such as sorghum, field corn and winter wheat. The USDA provides additional information on the effects of ozone air pollution on plants.

Chart depicted yield response of various crops due to seasonal ozone levels
Heagle, AS. 1989. Ozone and crop yield. Annual Review of Phytopathology 27:397-423.