The term "noxious" refers to substances or elements that are harmful or toxic to living organisms. This can include chemicals, plants, or even certain behaviors that can cause injury, illness, or death. For example, noxious weeds can invade ecosystems, outcompeting native plants and disrupting local wildlife. In addition to environmental concerns, noxious substances can also pose risks to human health. Exposure to noxious gases, such as carbon monoxide or sulfur dioxide, can lead to serious respiratory issues and other health problems. Understanding and managing noxious elements is crucial for maintaining a safe and healthy environment.