The indoor air pollution problem Modern, almost air-tight buildings with low fresh air exchange do not provide sufficient ventilation to remove indoor air contaminants. Boosting outside airflow would improve the indoor air quality, but it would be very costly in energy losses in heated or air-conditioned air. People spend on average 93 percent of their time indoors, which makes indoor air quality important to their health.
Indoor air is often more polluted than the outdoor air in our most polluted cities.
Openings in foundations and pores in concrete draw in moisture, which causes mildew, molds, excessive spores, mites, and pathogens. Ventilation and natural air movement then spread the biological and other pollutants throughout the building. The most common indoor biological contaminants are molds, mildew, bacteria, viruses, house dust mites, animal dander, cat saliva, and pollen. The particles are too small to be visible and travel suspended in air. The necessary pre-condition for biological growth is moisture.