There are many possible sources of air pollutants in homes. Following are some common sources/causes:

• renovation work
• burning of fuels in gas stoves and ovens
• building and furnishing materials
• new pressed-wood furniture
• using consumer products containing volatile organic compounds, such as cosmetics, fragrance products, cleaning agents and pesticides
• dry-cleaned clothing
• smoking
• damp environment causing mould growth
• poor housekeeping or inadequate cleaning
• poor ventilation causing accumulation of biological contaminants and other air pollutants

There are many possible sources of air pollutants in offices / public places. Following are some common types of pollutants:

Chemical pollutants

• ozone from photocopiers
• emissions from office equipment, furniture, wall and floor coverings
• consumer products containing volatile organic compounds, such as cleaning agents and pesticides

Airborne particles

• particles of dust, dirt, or other substances drawn into the building from outside
• activities in buildings, like sanding wood, printing, copying, operating equipment, and smoking

Biological contaminants

• excessive level of bacteria, viruses, and mould growth
• inadequate maintenance and housekeeping
• water problems, including water spills, leakages and condensation, not promptly and properly fixed
• inadequate humidity control
• brought into the building by occupants, infiltration, or through the fresh air intake