There are several rating systems for indoor air quality and how the indoor air quality can be determined from measuring TVOC concentrations.
The German Federal Environmental Agency translates TVOC concentration (parts per billion) on a logarithmic scale into five indoor air quality levels (IAQ), as shown in the table below.
Thereby the five stages or so called IAQ levels extend from Level 1 (excellent) to Level 5 (unhealthy). Extended exposure to increased IAQ levels, i.e. to bad air, can affect the comfort, well-being and health of building occupants. Poor indoor air quality is linked e.g. to sick building syndrome, reduced productivity and impaired learning in schools.
The World Health Organization (WHO) released indoor air quality guidelines for Europe which are classified by means of TVOC concentration values. Different air quality classes and their corresponding class limits in TVOC concentration are listed in Table below.
RESET Air for Commercial Interiors is a continuous monitoring and communication standard for indoor air quality with the goal of raising public awareness of indoor air quality and its impacts on environmental aspects and occupant health. Goal of the standard is continuous monitoring of particulate matter (PM2.5), TVOC and CO2 concentrations. Since long-term exposure to VOCs can cause damage to the liver, kidneys and the central nervous system, the RESET standard formulates IAQ performance targets for an average daily exposure to TVOC concentrations, as listed in Table below.
RESET™ Air Standard for Commercial Interiors v2.0, 2018. Translation from mass concentration [µg/m³] to particle concentration [ppb] is based on an average molar mass of TVOC molecules, according to the TVOC mix proposed by Mølhave (Ref.: Mølhave L, Clausen G, Berglund B, et al. (1997) Total Volatile Organic Compounds (TVOC) in Indoor Air Quality Investigations. Indoor Air 7:225-240). Thereby 4.9 µg/m³ corresponds to 1 ppb TVOC concentration.
LEED, or Leadership in Energy and Environmental Design, is the most widely used green building rating system. It aims for providing a framework to create healthy, highly efficient and cost-saving green buildings by providing globally recognized certifications. The LEED scoring function was developed based on the LEED TVOC limit of 500 µg/m³, as shown in Table below.
