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- Afshari, Alireza, 1956
(författare)
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Determination of VOC Emissions from Surface Coatings by Environmental Test Chamber Measurements
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The emitting properties of different building materials are obtained by measurements in environmental chambers of a few established designs. In order to interpret the results from the measurements and to predict the influence on the indoor environment, it is necessary to have a good understanding of the parameters governing the emission process. The aim of this thesis is to contribute to this understanding by focusing on the process of emission of chemicals from building materials and on the influence of a number of parameters governing the process. In emission studies reported in the literature, few investigations deal with the comparison of the VOC emission rates obtained by measurements in different test chambers. In the present study, a 1m3-chamber, a CLIMPAQ and a FLEC were used for measurement of the concentrations of various compounds from surface coatings. The study focuses on parameters which could be considered to have a substantial influence on the emission rates, or which do not appear to have been thoroughly studied previously. Interest has mainly been focused on the influence of air velocity, airflow rate and sorption on the emission rate, when other parameters have been maintained constant. It was found that during the first 24 hours, by varying the airflow rate under given test conditions in a test chamber, a number of physical parameters have a direct influence on the emission process. From the start of the test until steady state has been reached, the measured concentration variations may be divided into three different phases. The results from measurements showed that the higher the airflow rates, the faster a steady state was attained. Furthermore, all the selected substances did not reach steady state at the same time during the experiments. The effect of the air velocity above the surface on the emission of VOCs was studied in the three mentioned environmental chambers. It was found that the emission rates of the compounds at 22, 23 and 24 hours after the start of the test systematically increase with increasing air velocity. It was possible to determine the magnitude of increase to 10-20%. However, it was difficult to determine the exact level of increase of the emission rate, due to the uncertainty of the measurements and the low levels of increase. Finally, the characterisation of adsorption of VOCs on the inside of the empty chambers has been studied. The experimental studies for all three chambers show that the sorption of substances in the 1 m3-chamber was slightly lower than in the FLEC. The CLIMPAQ shows a larger capacity of sorption with material specimens than without material specimens. This indicates that the gases emitted from painted plates adsorb again onto the test materials.
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| 2. |
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| 3. |
- Afshari, Alireza, 1956, et al.
(författare)
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Impact of Ventilation Rate, Ozone and Limonene on Perceived Air Quality in Offices
- 2002
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Ingår i: Proceedings of the Indoor Air 2002 Conference.
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Konferensbidrag (refereegranskat)abstract
- The objective of this study has been to clarify to what extent ozone (03) and 03 !limonene in interaction with surface materials has an impact on the indoor air quality in typical low-polluting offices at various, realistic air change rates. Changes of environmental conditions were performed seven days before the chemical sampling. Organic compounds were collected on Tenax TA adsorbent tubes and the samples were analysed by gas chromatography with flame ionisation and mass selective detectors. The concentration of Total Volatile Organic Compounds were asexpected found to be inversely proportional to air change rates. Aldehydes and organic acids werefound at increased levels when the air change rate was decreased from 1.0 h1 to 0.3 h1. Increased ventilation rate to 3.0 h1 did not induce additional changes in the chemical composition of aldehydes and organic acids. The fractions of aldehydes and organic acids relative to nonreactive alkanes indicated that chemical transformation in the indoor environment indeed took place; however, it could not be clearly specified whether the chemical changes were of homogeneous or heterogeneous character. The effects of 03 and 03 /limonene in interaction with surface materials in the offices over seven weeks showed different reaction pattems depending material and treatment.
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| 4. |
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| 5. |
- Afshari, Alireza, 1956, et al.
(författare)
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Naborøg og overførsel af partielforurening
- 2010
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Ingår i: HVAC - Magasin for klima- og energiteknik, miljø, bygningsinstalltioner & -Netværk. ; 1:2010, s. 24-30
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Afshari, Alireza, 1956, et al.
(författare)
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Quantification of ultrafine particles from second-hand tobacco smoke infiltration
- 2010
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Ingår i: Proceedings of the CLIMA 2010 Conference: 10th REHVA World Congress 'Sustainable Energy use in Buildings', 8 pages.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents some of the results of a second-hand tobacco smoke intervention studycarried out in 19 flats in four different buildings. Two of the investigated buildings were nonrenovatedand two others were renovated. The aim of the study was to quantify infiltration ofultrafine particles from a smoker's flat into a non-smoker's flat. In addition, several tests werecarried out to describe some solutions for reduction of particle concentrations in the smoker'sflat and the non-smoker's flat. The air change rates and the indoor particle concentrationswere measured continuously during the measuring periods. The particle sources (particlegenerating activities) were cigarette-burning in the un-occupied buildings and candle-burningin the occupied buildings. Reductions of the concentration of ultrafine particles using aircleaning devices were studied. Results showed that the transfer of ultrafine particles wasabout 9% when the source flat was located below the receiving flat, whereas the transfer was1-2% when the source flat was on the same floor as, or above, the receiving flat.
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| 7. |
- 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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| 8. |
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| 9. |
- Shi, Bingbing, 1983, et al.
(författare)
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The effectiveness of portable air cleaners against tobacco smoke in multizone residential environments
- 2010
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Ingår i: Proceedings of the CLIMA 2010 Conference: 10th REHVA World Congress 'Sustainable Energy use in Buildings', 8 pages.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this study was to investigate how the effectiveness of portable air cleaners(ACs) against tobacco smoke is influenced by the clean air delivery rate (CADR), the locationof the AC in relation to the pollution source and the apartment structure. The study was basedon field experiments and simulations with the CONTAM software. The AC effectiveness wasabout 80% for one AC, and 93% for two ACs in the studied apartment (volume=110m3).Ultrafine particles (UFP) exposure in a room without tobacco smoking (clean room) could bemuch less than in the source room if these rooms were not directly connected with each other(but indirectly connected via doors open to other rooms). Operating the AC in one of therooms without cigarette smoking could develop a partly isolated clean environment.However, this led to a rather low cleaning effectiveness for the concentration of ultrafineparticles in the apartment as a whole. If operating the AC in the room where cigarettes arebeing smoked, the UFP exposure in the whole apartment can be further reduced.
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