Oxides of Nitrogen
Coal-fired power plants are a major source of NOx in our atmosphere, with a typical 500 MW plant emitting 10,200 tons per year.
NOx can cause serious health problems among those exposed to it—just ask Dr. Marcus Higi of Cortez, Colorado. Dr. Higi, of Cortez treats residents of the Navajo Nation, who are affected by pollution of two nearby power plants that drifts into their Reservation. The NOx emitted by the plants combines with volatile organic compounds to form ozone, which exacerbates asthma. Dr. Higi has treated five children with asthma attacks so severe he had to fly them out to area hospitals in order to save their lives. He has worked as a physician in other places, like Florida and the East Coast, but has never seen so many people greatly affected by asthma as in the Navajo Nation. “A kid would come in” to his practice, says Dr. Higi, “barely breathing. They’re basically on the verge of death.”
Chronic exposure, as is more common when living in an area near a coal-fired power plant, increases susceptibility to respiratory illnesses and causes permanent alterations in the lung. The ozone created from NOx not only causes asthma but also reduces lung function, causes adverse birth outcomes and increases allergen sensitization.
Like most air pollutants, NOx not only affects human health but also the health of the environment. The presence of NOx in the environment contributes to two main problems of acid rain and smog.
Acid Rain: When NOx is emitted from our power plants and enters the atmosphere, it can react with water droplets in clouds to form rain (or other precipitation) with an unusually low pH. Lakes and streams are extremely susceptible to acid raid, and populations of fish and other aquatic life can be devastated or even pushed to extinction due to acidified waterways. Acid rain also affects plant life, because it strips away vital plant nutrients that are necessary for healthy trees, plants and forests. Finally, acid rain is probably most famous for accelerating or causing the decay of monuments, sculptures and buildings that are historical and irreplaceable. The likelihood of acid rain damage is becoming so high that manufacturers of American cars are now spending $61 million per year on acid-resistant car paint.
Smog: Photochemical ozone, in addition to being harmful to health, is the culprit behind the brown clouds of smog that are most often seen over major cities, but are increasing in prevalence.