The statement 'General mechanical ventilation is the most effective type of ventilation' is:

• A. True
• B. False
• C. Not sure
• D. Depends on the situation

Answer: (B)

Capturing contaminants at the source is the most effective way to protect workers. General mechanical ventilation works by diluting and circulating air throughout the whole space, which helps with overall comfort and air quality but often doesn’t pull fumes, dust, or vapors away from the worker right where they’re generated. Local exhaust ventilation, on the other hand, is designed to capture emissions directly at the point of origin with sufficient capture velocity, pulling contaminant‑laden air into ducts before it can spread. Because of this direct removal, LEV is typically far more effective at reducing exposure for processes like grinding, welding, or polishing. General ventilation remains important for maintaining overall air quality and supplying fresh air, but it isn’t the most effective control for protecting workers from process emissions.