The Effects of Air Pollution on Plants

Pollution from car exhaust, factory emissions, fuel combustion and other sources can hang a brown cloud over some cities. Air pollution not only contributes to respiratory diseases in humans and damages buildings, it can also affect plants. The effects of air pollution on plants develop over time and can't be undone 2. Some plants are more susceptible to pollution damage than others according to Fred Davis, a chemist from Kent State University.

Leaf Damage

Chemicals such as sulfur dioxide, ozone, fluorides and peroxyacyl nitrate damage the leaves of plants. If enough leaves are damaged, the entire plant will die. Sulfur dioxide, a by-product of burning fossil fuels such as:

• oil
  
• coal
  
• gasoline
  
• causes changes in the colors of leaf tissue
  
• which may turn white
  
• brown or yellow

Slowed Growth

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Dr. Kent reports that nitrogen dioxide, a byproduct of combustion from car engines or open fires, can slow the growth of plants. Fortunately, rainfall transforms nitrogen dioxide into nitric acid, which adds nitrogen to the soil and actually benefits plants.

However, carbon monoxide is less benign. This component of car exhaust is poisonous to humans and will stunt the growth of plants. Some evergreens will drop their leaves completely when exposed to carbon monoxide.

Insect Infestation

Air pollution weakens plants and makes them more susceptible to insect infestation. The University of Colorado reports that pine trees stressed by air pollution are more susceptible to damage from pine bark beetles 1. A 2008 Newsweek story reported that pine beetles had destroyed 22 million acres of pine trees in Canada and more than 1.5 million acres in Colorado 3.