Dirt contaminates a pneumatic system. It is very similar to industrial smokestacks spewing soot. In an industrial environment, air carries several undesirable elements, as far as a pneumatic system is concerned. A compressor is protected by an intake filter which is engineered into the inlet by the compressor manufacturer. It is designed to remove dust particles commonly found in an industrial environment. Filtration is the first, and often the only, line of defense against contamination in a pneumatic system. Adequate filtration is seldom expensive and will return the investment many times over in improved component life and reduced downtime. Air leaving the compressor is usually not only saturated with water vapor, but has probably picked up oil vapor from the compressor. A typical industrial air filter should technically be described as a combination of a dynamic separator and a mechanical or static filter.