Air contaminants can get into our body through inhalation, skin absorption, ingestion and contact through wounds causing harm. The Occupational Safety & Health Regulation of the Labour Department requires the responsible person of the workplace to ensure the workplace is free of air contaminants and adopt measures to protect the workforce. The Environment Department also promote a voluntary indoor air quality monitoring scheme. This course aims to provide employers and other workplace responsible persons the knowledge about air contaminants, their ill effects and preventive measures.