Indoor air pollution refers to

• A. Air pollution inside buildings from things like mold, smoke, radon, asbestos, or chemicals.
• B. Pollution outdoors.
• C. Noise pollution inside buildings.
• D. Ultraviolet radiation indoors.

Answer: (A)

Indoor air pollution is about contaminants inside buildings that degrade the air you breathe. It includes mold spores, tobacco smoke, radon gas, asbestos fibers, and chemicals released from paints, cleaning products, and building materials. When a space is tightly sealed or poorly ventilated, these pollutants can build up and cause health effects like coughing, allergies, or asthma. This is different from outdoor air pollution, which comes from sources outside the building, and from issues like noise or UV radiation, which are not about the air quality inside. So the best description is pollutants originating inside buildings that affect indoor air quality.