Smog is made up, in large part, of ozone gas. When most people think of ozone, they think of the protective layer of ozone in the earth's upper atmosphere that protects us from harmful ultraviolet rays. At the ground level, however, ozone is a toxic gas. In 1990, Congress passed the Clean Air Act Amendments to combat high emission levels of carbon monoxide and nitrogen oxides, which react to form ground-level ozone. The effect smog has on humans is worse than you may think.
Air pollution has a enormous effect on public health.
Recent studies have linked ground level ozone pollution with increases in hospital admissions for respiratory conditions, especially among children with asthma, the elderly, and people with heart and lung disease. According to the American Lung Association, air pollution contributes to lung disease including asthma, lung cancer, and respiratory tract infections and close to 335,000 people in the United States die from lung disease every year. Almost a billion gallons of oil are spilled into the world's oceans and waterways each year. Acute oil spills, such as the Exxon Valdez marine oil spill in Alaska in 1989, can damage individual organisms and wipe out entire populations of marine and coastal species. Even more alarming, however, is that marine oil spills such as the Valdez spill are not nearly as damaging to the environment as the thousands of smaller spills that are reported annually.