IEQ

Indoor Environmental Quality (IEQ) is a measure of the overall quality of the indoor environment as it relates to occupant health, comfort, and performance. It encompasses several domains that affect perceived well-being and productivity within built spaces, including air quality, thermal conditions, lighting, acoustics, and the presence of materials and contaminants.

Air quality concerns include ventilation effectiveness, control of pollutants such as particulate matter (PM2.5), volatile organic compounds (VOCs), carbon dioxide, and humidity. Thermal environment covers temperature, humidity, radiant heat, and air velocity, with PMV/PPD models used to predict thermal comfort. Lighting considerations include illuminance, glare, color rendering, and daylighting. Acoustic quality involves sound levels, noise intrusion, and reverberation. Material choices influence surface emissions and moisture interactions, affecting IAQ and comfort.

Assessment combines objective measurements (sensor data for CO2, PM, VOCs, temperature, humidity, light and sound) with subjective surveys of occupants. Standards and guidelines such as ASHRAE Standard 62.1 for ventilation, ISO 7730 for thermal comfort, and green building rating systems (WELL, LEED) guide IEQ requirements.

Benefits of strong IEQ include improved health, reduced sick days, and enhanced concentration and performance. Challenges include balancing ventilation and energy use, controlling moisture to prevent mold, and ensuring consistent IAQ across spaces. Mitigation strategies include source control, adequate ventilation, filtration, humidity management, daylighting, acoustic design, and low-emission materials.

IEQ is a central concern in offices, schools, healthcare facilities, and homes. It is increasingly integrated into building codes, certification programs, and performance tracking to support healthier, more productive indoor environments.