What are volatile organic compounds (VOCs)? Give some examples of VOC sources.

Volatile organic compounds (VOCs) are organic chemicals that easily evaporate at room temperature. They typically consist of carbon and hydrogen, and may include other elements such as oxygen, nitrogen, halogens, and sulfur. VOCs are found in various sources, both natural and human-made. They can cause adverse health effects, depending on the specific compound and concentration.

The following are some examples of sources for volatile organic compounds (VOCs): 1. Natural sources a. Emissions from plants: Some plants release VOCs, such as terpenes, as part of their metabolic processes. For example, the scent of pine trees comes from terpenes, a type of VOC. b. Microbial emissions: Certain bacteria and fungi produce VOCs, such as methane. 2. Human-made sources a. Household products: Many household products contain VOCs, including paint, cleaning supplies, adhesives, air fresheners, and pesticides. b. Building materials: Some building materials release VOCs over time, such as formaldehyde present in pressed wood products, or solvents in paints and coatings. c. Industrial processes: A variety of industrial processes emit VOCs, including manufacturing, petroleum refining, and chemical production. d. Vehicle emissions: Gasoline and diesel engines produce VOCs, such as benzene and toluene, as part of the combustion process. Additionally, gasoline vapors released during vehicle refueling are a source of VOCs. These are just a few examples of the many diverse sources of volatile organic compounds that can be found in the environment and human activities.