In the late 1970s, the energy crisis caused buildings to be designed to save energy. Energy efficiency was to be influenced by the so-called super-insulation and reduced fresh air exchange. However, it was noticed that too tight a tightness of rooms led to health problems such as dry eyes, headaches, and upper respiratory problems among employees in new buildings. Limited ventilation led to the so-called "sick building syndrome", i.e. lack of fresh air circulation leading to problems with the respiratory system. In the late 1980s, the National Aeronautics and Space Administration (NASA) in cooperation with the Associated Landscape Contractors of America (ALCA) proposed an economic solution to this problem using natural air filters - plants. Studies have been carried out to check the effectiveness of house plants in reducing the amount of everyday pollutants present in the air. 18 plants were used in the experiments to reduce the concentration of benzene, trichlorethylene (TCE) and formaldehyde. A home air purification system was designed using a potted plant and activated carbon.