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Volatile Organic Compounds in indoor environments

Advisory report | 23-05-2000

This report, prepared by an ad hoc committee for the Dutch Health Council, determines the volatile organic compounds (VOC) which may emit from building materials or other sources into the indoor environment. The VOC considered in this report are limited by the ’analytical window’ determined through existing standardized methodology for sampling and chemical analysis of VOC. Gaseous and very volatile organic compounds, semi-volatile compounds and compounds associated with particulate matter in air fall outside this analytical window. VOC concentrations in the literature vary considerably and generally are very low. The potential effects on human health caused by VOC within the analytical window are described. The biological effects caused bij the reported VOC concentrations seem to be limited to chemo-sensory reactions, such as odour and sensory irritation of the nose and eyes and have a relationship with the patterns of complaints recorded from volunteers in climate chamber studies and from residents living or working in buildings indicated as ’sick buildings’. Overall these data show that at these VOC concentrations the effects may sometimes be considered as nuisance. In order to make an assessment of potential health effects existing limit values like the HBROEL (Health Based Recommended Occupational Exposure Limit) and the derived OEL (Occupational Exposure Limit) were considered. The committee is of the opinion that these limit values cannot be used for this purpose. The duration of exposure and the kind of population defined to determine these recommended limit values differ too much from the situation for indoor air. The predicting value for the low VOC concentrations as measured in indoor air is far too low, also after the introduction of the usual safety factors. The committee also considers the use of the Air Quality Guidelines for outdoor air, as developed for the World Health Organisation, less useful as such guidelines have been developed for only a few organic compounds.

The committee concluded that chemo-sensoric reactions may be considered a useful biological basis in determining a limit value for VOC in indoor air and is of the opinion that in this way any influence on the health of those concerned will be prevented, including effects on well-being following chemo-sensoric reactions. This was considered to be in line with the generally accepted understanding within the building industry that indoor air quality should not raise any complaint. The relevant VOC concentration in indoor air was estimated to be 0.2 mg/m3.

The health risk assessment procedure for substances emitting from building materials follows a number of steps. Firstly the emission from the building material must be determined and secondly the resulting VOC concentrations in indoor air should be estimated. The methodology for this last step is available, but has not yet been fully developed. Any result must be interpreted with care due to the limitations introduced by the ’analytical window’, the way of sampling in the test chamber and the uncertainties being introduced when calculating the VOC immissions in indoor air from the measured VOC emissions. In the final step of this procedure the estimated VOC concentration must be compared with the recommended value of 0.2 mg/m3.

This approach does not take into account the health risks that can be attributed to individual VOC. Any risk resulting from the use of carcinogenic, reprotoxic or sensitising substances in the production of building materials should be avoided. In cases where the use of such substances is still considered a separate risk assessment is required.

In summary the committee concluded:

  • The existing analytical window provides a limitation to the information on VOC emitting from building materials; attention should also be given to substances outside this window.
  • The maximal permissible pollution by VOC of indoor air, e.g. the immission measured within a comparable analytical window, is estimated to be between 0.2 and 3.0 mg/m3; VOC concentrations above 0.2 mg/m3 may better be avoided.
  • Measured levels of emissions from materials placed in test chambers need translation into a representative level for the immission in indoor environments prior to comparison with the given limit value. The procedure for this translation has not yet been developed technologically. The committee advises to develop such a model.
  • The application in the production of building materials of individual VOC with carcinogenic, reprotoxic or sensitising properties should be avoided.
  • The preventive application of the given limit value as a health criterion does not exclude the possibility of indoor air pollution from building materials. Failures at production, the introduction of new materials and the transfer to other raw materials during production could all form a new source for VOC as well as for substances outside the ’analytical window’.
  • The available immission data have mainly been produced ten or more years ago. An update may be required in view of recent developments in the buidlding industry and in the ways buildings and houses are being used.