Does anyone know the effect on indoor air pollution?

Its for a school project, so please help....

the effect of indoor air pollution on what?

lungs problem

Yes, I actually investigated it myself. The sites below are the places I found most helpful.
Basically, the quality of the air varies in every home. Some homes have out-gassing from plastics and new materials like carpet. Other homes have carbon monoxide in small levels which can cause problems over time. Second-hand smoke irritates the lungs, especially those of people who have asthma. and the ionizing air filters can cause problems for asthmatic people as well by creating ozone in the air -- ozone is O3 molecules and, at low doses cause problems for many people. If you live in a city, they have warnings about ozone in the downtown areas. They aren't helpful for keeping the air clean unless you use them on a level so high that it would kill every living thing in the room. (Many ozonators claim they kill germs. It's only true if the O3 concentrations are high enough to kill bacteria...and that is also high enough to kill humans...)
Good luck on your project!