Earth Science
Human Impacts on the Earth Environment
Causes of Air Pollution
Study Tip
In large car-dependent cities, up to 85% of air pollution can come from car emissions.
Fossil Fuels
- Fossil fuels are burned for automobiles, power plants, and industrial plants. These do not always burn completely, and incomplete chemical reactions will create pollutants.
- Pollutants include carbon monoxide, nitrogen dioxide, sulfur dioxide, and hydrocarbons.
Study Tip
In large car-dependent cities, up to 85% of air pollution can come from car emissions.
Biomass Burning
- Burning animal and plants directly can also cause pollution.
- Biomass is the total amount of living material found in an environment. Biomass is mainly burned through slash-and-burn agriculture. (Biomass is cut down and burned to make room for human farming.)
- Burning biomass can produce the same pollutants as burning fossil fuels.
- It worsens greenhouse gases, since the trees that store carbon dioxide are now cut down.
A forest that has been slash-and-burned to make new farmland
Evaporation
- Volatile organic compounds (VOCs) enter the atmosphere through evaporation. The most common one is methane.
- They come from human-made products such as paint-thinner, cleaning solvents, preservatives, and other liquids.
Concept Check
- What are some air pollutants?
- What is slash-and-burn agriculture? Why does it worsen the greenhouse gas effect?
- What are VOCs? Where do they come from?
