The presence of Volatile Organic Compounds (VOC) in indoor air has in past decades often been associated with adverse health effects such as sensory irritation, odour and the more complex set of symptoms called the Sick Building Syndrome (SBS). More recently, a possible link between the increase in the prevalence of allergies throughout the industrialized areas of the world and exposure to elevated concentrations of VOCs has been suggested. In many cases, the total VOC (TVOC) is used as a measure of the concentration of air pollution and, by extension, as a measure of the health risk in non‐industrial buildings. However, the TVOC concept has been questioned for a number of reasons, including the facts that it is an ambiguous concept, that individual VOCs making up the whole can be expected to give rise to different effects in people and that researchers have been using different definitions and interpretations of TVOC. This means that simple addition of the quantities of individual VOCs may not be relevant from a health point of view. Twelve researchers from the Nordic countries have reviewed the literature on VOC/TVOC and health. A search of the literature resulted in the identification of about 1100 articles, of which 120 were selected for further examination. A final review of the articles reduced their number to 67 that contained data on both exposure and health effects. The group concluded that indoor air pollution including VOC is most likely a cause of health effects and comfort problems in indoor environments in non‐industrial buildings. However, the scientific literature is inconclusive with respect to TVOC as a risk index for health and comfort effects in buildings. Consequently, there is at present an inadequate scientific basis on which to establish limit values/guidelines for TVOC, both for air concentrations, and for emissions from building materials. The group concluded that continued research is required to establish a risk index for health and comfort effects for VOC in non‐industrial buildings.
The content of polycyclic aromatic hydrocarbons (PAH) in the work atmosphere of a coke plant was investigated on two occasions. Stationary, mobile, and personal sampling were used, and the samples were analyzed by glass capillary gas chromatography. Up to 39 PAH and heterocyclic compounds were identified in the samples. By personal sampling, the occupational exposure to PAH was determined to vary between 5 and 1,000 mg/m 3 . A study of the occurrence of PAH on particulate matter revealed that 98 % of the PAH was respirable. No significant variation in the relative distribution of the PAH components (PAH profile) was observed during the two sampling periods. The PAH profile for the coke plant was similar to that of a SOderberg aluminum plant, but different from that of a Soderberg paste plant.
A simple test chamber method to quantify adsorption and desorption of organic compounds on material surfaces is described. Important environmental parameters such as temperature, relative humidity and air velocity were varied and controlled independently around typical indoor values. Experiments were performed with alpha-pinene and toluene in concentrations of 160-300 micrograms/m3. The measurements show adsorption on and desorption from wool carpet, nylon carpet, polyvinyl chloride (PVC) floor coverings, cotton curtain material and the empty chamber. The ranking of the materials, with respect to their sorption capacity, is as mentioned above. The adsorption of alpha-pinene was higher than the adsorption of toluene for all the materials. Air velocity was not found to influence the sorption of alpha-pinene and toluene on wool carpet, tested with air velocities at 0, 10 and 20 cm/s. The experiments were carried out during both the adsorption and the desorption phase. The uncertainty of the experiments was lowest during the desorption phase. Based on the results obtained, it can be recommended that sorption experiments should be performed as desorption phase experiments. A one-sink model, based on the Langmuir adsorption isotherm, appears adequate to describe the results.
A sink-diffusion model to describe the interaction between material surfaces and volatile organic compounds (VOCs) in indoor air has been introduced. The model is based on adsorption/desorption on the material surfaces and diffusion into the materials. Test chamber experiments with exposure of nylon carpet and polyvinyl chloride (PVC) covering against alpha-pinene and toluene were used to validate the model and to make comparisons with a sink model based on the Langmuir adsorption isotherm. The results showed that the sink-diffusion model gave a better description of the desorption curve than the Langmuir model. The model predictions improved with increasing sorption effect. The Langmuir model gave good predictions of relative weak sorption effects, whereas the sink-diffusion model improved the predictions for stronger sorption effects. In this case, nylon carpet showed substantial stronger sorption than PVC covering and alpha-pinene showed stronger sorption than toluene. Controlled field experiments with combinations of building materials and a mixture of VOCs, encountered in real indoor environments, are needed to further validate the sink-diffusion model.
The content of polycyclic aromatic hydrocarbons (PAH) in a Sederberg prebaked aluminum reduction plant and an anode plant was studied. Both stationary and personal sampling were used, and the samples were analyred by glass capillary galS chroma,tography. In many samples more than 30 PAH and heterocyclic compounds were identified. Comparison of tberesullts~rom Ithe different planJts revealed 1lha,t the atmospheric P AH content was signHiicantly higher in the Seder,berg plant than in the others. However, the relaillive dist,ribullion of PAH components (PAH profile) was relatively constant :in ,the prebaked and the anode lba1cing plant, ,and different in the Sederberg plan'1;. As a consequence of the va,riaiion [n the po11ullion 'level among the dUferent job caJtegories, personal sampling showed a broader -range of PAH concenrt;rations than the staillionary method.
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