There are a variety of different methods that can be used to perform air sampling. Each approach has advantages and disadvantages, and the best approach depends on a combination of available resources, necessary applications, and potential health risks from the workplace. For example, for workplaces with high levels of hazardous or toxic gases, continuous monitoring of air composition may be a legal and safety requirement for health. Dangers from gases, vapors, dust, and fibers in the air can cause potentially life-threatening illnesses that affect the lungs, kidneys, and liver.