TVOC concept

The following recommendation regarding the application of TVOC values renders Seifert s TVOC concept of 1999 in more precise terms (Seifert, 1999). The scheme recommended in Table 9.2 is subdivided into five levels which allow room for interpretation in their transitional regions (Ad-hoc AG, 2007). These levels will be... 

After the first experiment with low level exposures to a mixture of VOCs had demonstrated that unexpected health and comfort effects may follow from low level exposures (M0lhave, Bach and Pedersen, 1986), the concept of TVOCs was suggested as a measure of a mixture s potency to cause effects. The concept was recently revised (Andersson et al., 1997 M0lhave and Nielsen, 1992 M0lhave et al., 1997 Seifert, 1999). This TVOC concept is still debated. Undoubtedly, it is based on several assumptions that are not yet justified and its general usefulness for the prediction of effects of mixtures other than the M22-mixture (see below) is undocumented. The appealing aspect of the indicator is that it is easy to measure and use in pollution control and regulation. 

The TVOC concept has limited use and must be used with caution [119]. 

The various proposed TVOC target values in Table 4.1-3 are all in good agreement with the concept outlined by Seifert and cover a range from 200 pg/m to 600 pg/m. Recently Seifert (1999) published a revised version of his TVOC concept recommending officially intervention if the TVOC concentration exceeds a range of 1000 pg/m to... 

Fitzner and Finke, 1996), nonetheless the TVOC concept seems to be appropriate to establish a general indicator for an acceptable (chemical) indoor climate. 

In their report, the EU-ECA-WG 13 (1996) discusses the advantages and disadvantages of the TVOC concept in respect of exposure assessment and prediction of health effects. The report has also been published as Mplhave et al., 1997. The recommendations cited from their report in this Chapter are in italics. 

The possibility cannot be excluded that specific VOCs appear indoors which may turn out in the future to he much more potent in causing effects on humans than the average VOCs. In this case, these (e.g. formaldehyde) should be evaluated individually, and a list of such compounds should be established. A draft list of special compounds for which low thresholds for effects or high detection limits cause the probability of sensory effects to be grossly underestimated if this TVOC-concept is used has not yet been officially established. This list should also include compounds which are likely to cause other types of health effects than irritation and which, therefore, must be considered in a total evaluation of the indoor air quality. Potential candidates for the list are mentioned above. 

The WHO definition of VOCs refers to the behavior of the compounds in traditional analytical procedures and not to their ability to cause discomfort and health effects through environmental exposures. Also, some organic compounds outside the VOC range as defined by WHO may contribute to relevant sensory effects. Consequently, the organic compounds relevant to the TVOC concept from the toxicologist s point of view may not be defined strictly by the WHO definition. However, no exact definition of the relevant compounds can be made at present. The pragmatic short cut suggested by... 

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