Question

what pollutes air indoors?

Answer 1

There are some reasons of polluted air indoors.
For example, moldy mushrooms. This type of mushrooms appears in the wet rooms. Also air indoors may be polluted because of bad furniture material. Bad furniture material carries toxins and harmful gases. If you haven't got house plants and you don't aerate rooms, your air will be polluted too. Sometimes a source of air pollution may be a house cleaning: some chemicals have adverse composition, that's able to pollute air indoors.