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- Lundgren, Björn, 1941, et al.
(författare)
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Air quality in offices, impact of ventilation rate, ozone and limonene
- 2003
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Ingår i: The 4th international conference on Cold Climat HVAC.
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Konferensbidrag (refereegranskat)abstract
- The objective of this study has been to clarify to what extent ozone (O3) and O3 /limonene in interaction with surface materials has an impact on the indoor air quality in typical low-polluting offices at realistic outdoor air change rates. Three similar offices furnished with the same materials and ventilated with charcoal filtered outdoor air were used in the study. Eight environmental conditions with different realistic combinations of air change rate, O3 and limonene levels were studied. Changes of environmental conditions were performed seven days before the first chemical sampling was performed at set conditions. Decreasing the air change rate from 1.0 to 0.3 h-1 increased the levels of volatile organic compounds in the indoor air. The presence of ozone affected the level and fraction of aldehydes proposing chemical transformations. Adding new materials to the offices at a low air change rate of 0.3 h-1 demonstrated a variable effect depending on the specific air quality in the room. Normal concentration of O3 in indoor environment contributes to chemical transformations even in low-polluted offices.
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- Örtengren, Ulf, 1959, et al.
(författare)
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Influence of pH and time on organic substance release from a model dental composite: a fluorescence spectrophotometry and gas chromatography/mass spectrometry analysis.
- 2004
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Ingår i: European journal of oral sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 112:6, s. 530-7
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Tidskriftsartikel (refereegranskat)abstract
- In this study we assessed the influence of pH and time on the degradation and elution of organic substances from the composite resin material, Z-100. To accomplish this, fluorescence spectrophotometry was evaluated as an appropriate technique for the identification of six organic substances (methacrylic acid, methyl methacrylate, hydroquinone, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate and 4,4'-isopropylidenediphenol) that were eluted from resin composite material stored for 24 h or 6 months at pH 4.0, 6.0 or 8.0. In addition, complementary analyses (solid-phase microextraction/gas chromatography/mass spectrometry) were carried out to identify and quantify the substances. The main substances leached from the resin composite were methacrylic acid, triethylene glycol dimethacrylate and hydroquinone. It was concluded that fluorescence spectrophotometry seems to be a suitable, non-destructive technique for the qualitative analysis of eluted organic components. Critical combinations of time and pH allowed the elution of several organic substances, predominantly methacrylic acid, triethylene glycol dimethacrylate and hydroquinone, from the model resin composite, Z-100.
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