Which statement best differentiates local exhaust ventilation from general ventilation?

Which statement best differentiates local exhaust ventilation from general ventilation?

• A. Local exhaust captures contaminants at the source; general ventilation dilutes contaminants in the overall space.
• B. Local exhaust dilutes contaminants in the space; general ventilation captures contaminants at the source.
• C. They are identical in function.
• D. General ventilation captures contaminants at the source.

Answer: (A)

Local exhaust ventilation is all about capturing contaminants where they’re produced. A hood, capture device, or ducted exhaust sits right at the source and pulls the pollutant away before it can spread, giving you targeted removal and protection for the worker’s breathing zone. General ventilation, by contrast, moves and mixes room air to dilute contaminants throughout the space, lowering overall concentrations but not pulling them out at the point of origin. So the best description is that local exhaust captures at the source, while general ventilation dilutes in the space. The other ideas mix up this distinction or claim they’re the same, which doesn’t reflect how these systems are designed to protect health.

Local exhaust ventilation is all about capturing contaminants where they’re produced. A hood, capture device, or ducted exhaust sits right at the source and pulls the pollutant away before it can spread, giving you targeted removal and protection for the worker’s breathing zone. General ventilation, by contrast, moves and mixes room air to dilute contaminants throughout the space, lowering overall concentrations but not pulling them out at the point of origin. So the best description is that local exhaust captures at the source, while general ventilation dilutes in the space. The other ideas mix up this distinction or claim they’re the same, which doesn’t reflect how these systems are designed to protect health.