What Is the Major Component of Smog?

Modern smog is caused by the photo-chemical reaction of a mixture of man-made pollutants, heat and sunlight. Combined together under the right circumstances they produce smog’s main component: ozone. This colorless gas is found naturally in the Earth’s upper atmosphere where it acts as a shield against the sun’s harmful ultraviolet rays but when it forms close to the ground it can cause problems to your health and can even damage crops, trees and vegetation.

Formation

• Ground-level ozone, as it is known, is formed through a chemical reaction when Nitrogen Dioxide and Hydrocarbons are combined and react together in the presence of sunlight. The chemicals involved in the creation of ground-level ozone are mainly released into the air as exhaust fumes from automobiles, factories, power plants and even certain consumer products. Temperature also plays a major role in how quickly smog forms and how long it will last, with higher temperatures usually resulting in more severe occurrences.

Health Effects

• While smog contains a mixture of noxious chemicals hazardous to human health, ozone has been found to have the single most detrimental effect and exposure has been shown to have several short-term health effects in the lungs. According to the U.S. Environmental Protection Agency, exposure to ozone is known to irritate the respiratory system, reduce lung function and aggravate asthma--as well as inflame and damage the lining of the lung. Researchers also suspect that ozone exposure may aggravate more serious lung diseases such as emphysema and bronchitis.

Symptoms

• According to Airnow.gov, people exposed to ground-level ozone will often experience symptoms which can include “coughing, irritation in the airways, rapid or shallow breathing, and discomfort when breathing or general discomfort in the chest. People with asthma may experience asthma attacks.” However, damage from ozone exposure may not always manifest symptoms and may even appear to fade over time but can still be causing damage to your lungs even though the symptoms have disappeared.

Risk Groups

• There are, according to airnow.gov, four groups of people who are most susceptible to ozone exposure. Active children are the highest risk group, as they spend the majority of their time outdoors and are at higher risk of having asthma. Adults who spend time outside exercising or working are the second group, while people with respiratory diseases such as asthma, make up the third group. The fourth group includes people who are naturally susceptible to ozone.

Remediation

• In 1990, the United States Congress revised and expanded the Clean Air Act in an attempt to enforce regulations implemented to reduce air pollution, including ozone. The act set out guidelines to decrease the amount of pollutants released and included changes in the composition of gasoline and the promotion of alternative fuels, such as natural gas and electricity. Localized programs such as carpooling, restricting traffic in congested areas, and the expansion of transportation systems are also being utilized in the fight against smog.