People spend most of their time indoors. Therefore, indoor air quality is an important public health issue, as people are exposed to pollutants there, including gases and particles, which come from outdoors to the inside of a building. Pollutants may also be generated indoors by cooking, candle burning, emissions from building material, etc. There is an increasing range of adverse health effects linked to air pollution, at an even lower concentration of pollutants. Increased ventilation is commonly discussed by researchers as a solution for reducing particle concentration in the indoor air. Recirculation of air through portable air cleaners has also been discussed. A large variety of air filtration technologies are commercially available for removing air pollutants. Different technologies are based on different air filtration mechanisms and are able to remove different pollutants. The scope and purpose of this Special Issue is to collect research data in order to clarify possibilities, applications, and limitations of using recirculated air in combination with new air cleaning technologies in order to improve indoor air quality. The objective is to clarify the effectiveness of portable air cleaners and to investigate the approaches of using these devices, aiming at reducing the concentration of particles and gases in the indoor environment.
Keywords: air cleaning; indoor air quality; ventilation; particles; gases.