Ground-level ozone, or “smog,” is caused when reactive organic compounds and oxides of nitrogen get “cooked” in the lower atmosphere by the sun’s ultraviolet rays. Ozone created in one part of the Bay Area can easily travel to other parts of the region due to local air currents and become trapped by geographical features like low-lying valleys.
Ozone can cause coughing, headaches, and eye, nose, and throat irritation. Symptoms may last for a few hours after ozone exposure and even become painful.
Lung function is based on the amount of air drawn in with a full breath and the speed at which it is exhaled. Ozone can make it more difficult to breathe as deeply and quickly as normal.
When ozone levels are high, more people have asthma attacks. Ozone makes people more sensitive to allergens, such as dust mites, pets, and pollen, which are the most common triggers of asthma attacks.
Ozone’s effect on the lining of the lung is similar to that of a sunburn on the skin. It damages the cells that line the air spaces in the lung. Within a few days, however, the damaged cells are usually repaired, just as skin recovers from sunburn naturally.
Most of the health effects of ozone are considered short term as they eventually cease once ozone levels subside. However, there is evidence that repeated short-term damage from ozone exposure may permanently injure the lungs. Other studies in heavily polluted areas have linked prolonged exposure to ozone to the development of asthma in children.
Ozone pollution also has environmental effects of ozone. These include:
Scientists believe that the impacts of ground-level ozone on long-lived species – such as trees – add up over many years, so that whole forests or ecosystems can be affected.