The pollutants inside our home are more concentrated than outside since, in addition to the pollution that can be filtered from outside there are several sources of pollutants inside the home itself. For example, the inhabitants themselves or even pets.
Tobacco smoke is one of the most prominent pollutants, but you also have to take into account others such as water and humidity, which contribute to the appearance of molds, fungi, allergens and bacteria. Another source of pollution are the materials used in construction and furniture, which emit a series of volatile organic compounds that float in the air and can be harmful to your health. Likewise, the chemicals we use for cleaning, air fresheners, pesticides, paints, etc., are a source of exposure to dangerous particles.
Careless maintenance of the home and its equipment can also lead to contamination. Cracks in the walls, for example, allow the infiltration of radon gas, which also has harmful health effects.