Pop quiz: which is more polluted, indoor air or outdoor air? 10 times out of 10, indoor air in your house, office or apartment is going to be worse than the air outside. Indoor air pollution has been ranked among the top 5 greatest risks to public health by the EPA, and stagnant indoor air allows pollutants to build up and stick to the things inside of your home.
The things in our homes emit some nasty toxic chemicals like formaldehyde for example. You can also be impacted by pollutants like pollen, bacteria, mold, and various outdoor contaminants that find their way inside.