Noxious gas refers to harmful gases that can cause injury, illness, or death to living organisms. These gases can be produced from various sources, including industrial processes, vehicle emissions, and natural events like volcanic eruptions. Common examples include carbon monoxide, sulfur dioxide, and ammonia. Exposure to noxious gases can lead to respiratory problems, skin irritation, and other health issues. Safety measures, such as proper ventilation and protective equipment, are essential in environments where these gases may be present. Monitoring air quality is crucial to protect public health and the environment from the dangers of noxious gases.