Pollution is defined as the undesirable change in the physical, chemical, or biological characteristics of air, water, and soil that can harm living organisms. There are several common types of pollution including noise, air, water, and land pollution. Noise pollution occurs when there are unwanted or excessive sounds that negatively impact human or environmental health. Air pollution results from both primary pollutants emitted directly and secondary pollutants formed from atmospheric interactions. Water pollution involves harmful substances in bodies of water. Land pollution degrades the earth's surface through improper waste disposal and misuse of resources. All forms of pollution can damage human health and the environment if not properly controlled and prevented.