Whether you keep a backyard garden or maintain a large farm, your plants are dependent on their environment. Environmental pollution can harm plants every bit as drastically as droughts, frosts, diseases and other natural phenomena. By understanding the effects of pollutants on plants, you can come to appreciate the importance of preserving the natural world.
Burning fossil fuels such as gasoline and coal releases carbon monoxide, nitrogen oxides and airborne volatile organic hydrocarbons, or VOCs. Sunlight can cause these different compounds to react, creating ozone as one of the byproducts. Ozone enters the leaves as the plant respirates. Ozone pollution can damage the ability of the leaves to form chlorophyll. This damages the plant's ability to photosynthesize, and can damage the leaves or even stunt or kill the plant.
Air pollution also harms plants by contributing to water pollution. Sulfur dioxide and nitrous oxides acidify water in the atmosphere, creating acid rain. Acid rain can damage the leaves of plants. It can also acidify the soil, making it unfit for native plants which depend on a certain soil acidity. Acid rain also acidifies lakes, streams and rivers, harming aquatic plants.
Burning fossil fuels, tilling fields, industrial manufacturing and other activities can release small particles of ash, smoke, dirt and other pollutants into the air. This sort of air pollution, called particulate matter, can interfere with the sunlight plants need to photosynthesize. Particles deflect and scatter sunlight while they are in the air. They also settle on plants, creating a film that prevents sunlight from penetrating into the leaves. This interferes with the the plants' ability to create food.