Local Exhaust Ventilation
This system of ventilation is provided at or near the point of generation of contaminants in the work area .Where as the mechanical ventilation only partly removes the contaminants from the working atmosphere ,while the local exhaust system achieves complete exhaust of contaminants from the work area .This system is cheap when compared to mechanical ventilation.Since the filtering units required occupies only a small area of point of generation of contaminants