LEV systems are designed to capture pollutants at the source, before they have a chance to spread throughout the work area. They consist of a series of hoods, ducts, and filters that work together to extract contaminated air and transport it away from the workers. This is typically done through the use of a fan or blower, which pulls the contaminated air into the hoods and then pushes it through the ducts and filters before discharging it into the atmosphere.