Which condition is a typical example of indoor air pollution?

• A. Brownish outdoor smog.
• B. Indoor air pollution includes mold, smoke, radon, asbestos, or chemicals.
• C. Acid rain deposition.
• D. Ozone layer depletion.

Answer: (B)

Indoor air pollution refers to contaminants that originate indoors or accumulate inside buildings, affecting the air we breathe. Typical indoor pollutants include mold from damp areas, tobacco or cooking smoke, radon gas that seeps in from the soil, asbestos fibers in older insulation or flooring, and chemicals released by cleaning products, paints, solvents, and furnishings. These substances can irritate the eyes, nose, and throat, trigger allergies and asthma, and, in some cases like radon and asbestos, increase cancer risk. The other options describe issues that mainly occur outside the building or in the atmosphere—outdoor smog, acid rain, and ozone layer depletion—rather than common indoor pollutants. So the example that best fits indoor air pollution is the list that includes mold, smoke, radon, asbestos, and chemicals.