Question

what is not a form of indoor pollution?
radon
tobacco
ammonia
ozone

Explanation:

Radon (from soil/gas), tobacco (smoke indoors), and ammonia (from cleaning products, etc.) are indoor pollutants. Ozone is mainly an outdoor pollutant (from photochemical smog) or in specific indoor devices but not a typical indoor pollution source like the others.

Answer:

D. ozone