Abstract
In Norway, mechanical ventilation is widely used in workplaces to maintain indoor air quality (IAQ). However, during winter, heating cold outdoor air often results in low relative humidity (RH), leading to discomfort such as dryness of the skin, eyes, and respiratory system. Recirculation of return air, an energy-saving method, helps maintain moisture but is typically discouraged due to concerns about airborne contaminants. Despite this, recirculation is increasingly used to achieve energy savings and meet climate goals for 2030.
This paper forms part of the Recirculate IT research project, which investigates the impact of air recirculation on indoor environmental quality in industrial and non-industrial pilot buildings. This narrative review focuses specifically on the use of air recirculation in selected industrial settings, which face similar challenges to some of the pilot buildings involved in the project. The studies included in this review focus on different types of occupational exposures and have been conducted by various disciplines, with some studies providing limited details on ventilation strategy and filtration technology. This makes it difficult to determine how, when, or even if recirculated air can be used. Taking this holistic approach will be the challenge for the Recirculate IT project: documenting the ventilation strategies, including outdoor air supply, recirculated air volumes, and filtration solutions, and in details determine how this affects the concentration of physical, chemical and biological components in various industrial work environments.