According to Surià, these concentrations of toxins, which are higher in the interior spaces, are due to insufficient ventilation and also to an artificial environment caused by the plastics and synthetic materials in the home, which causes an electrostatically charged environment to be generated that increases the concentration of dust in the interior environment. The harmful substances that are generated adhere to this dust and remain in the air.
Among the most common pollutants with higher household values are:
–Organic substances: for example, solvents or aromatic hydrocarbons, which cause respiratory problems, eye and throat irritation, dizziness, irritability and difficulty in concentration.
–Radon gas: is the second cause of lung cancer. Naturally problematic in areas with granitic soils such as Galicia or with sandstone such as El Maresme (Barcelona). Users increase this pollutant by insufficiently ventilating and introducing radon-emitting materials into the home, such as granite in kitchens.
–Biological contamination: for example, fungi and mites, which cause effects on the respiratory tract. Their presence is increasing in homes as homes are rehabilitated and thermal insulation is increased to save energy without due precaution. It is frequently reformed without allowing water vapour permeability, which condenses on cold facade walls where fungi expand. In these spaces the humidity increases and the appropriate conditions are formed for the proliferation of mites in mattresses or curtains.
–Domestic dust: Penetrate the respiratory system with breathing. They are among the worst pollutants for human health and more frequent the more electrostatic charge there is in the environment. The finest particles can reach the pulmonary alveoli and from there carry harmful substances in very sensitive areas and aggravate pathologies.