Per Axel Clausen

Dr. Per Axel Clausen

National Research Centre for the Working Environment, Copenhagen, Hovedstaden, Denmark
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Research Focus & Metrics

Academic Career Length

41Years (1986-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 July 2011 in ACS Nano
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Journal Article
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JPJaana Palomäki
Jaana Palomäki
EVElina Välimäki
Elina Välimäki
JSJukka Sund
Jukka Sund
MVMinnamari Vippola
Minnamari Vippola
PCPer Axel Clausen
Per Axel Clausen
HAHarri Alenius
Harri Alenius

1 February 2006 in Indoor Air
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Journal Article
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PWPeder Wolkoff
Peder Wolkoff
CWC. K. Wilkins
C. K. Wilkins
PCPer Axel Clausen
Per Axel Clausen
GNG. D. Nielsen
G. D. Nielsen
Sensory irritation and odor effects of organic compounds in indoor environments are reviewed. It is proposed to subdivide volatile organic compounds (VOCs) into four categories: (i) chemically non-reactive, (ii) chemically 'reactive', (iii) biologically reactive (i.e. form chemical bonds to receptor sites in mucous membranes) and (iv) toxic compounds. Chemically non-reactive VOCs are considered non-irritants at typical indoor air levels. However, compounds with low odor thresholds contribute to the overall perception of the indoor air quality. Reported sensory irritation may be the result of odor annoyance. It appears that odor thresholds for many VOCs probably are considerably lower than previously reported. This explains why many building materials persistently are perceived as odorous, although the concentrations of the detected organic compounds are close to or below their reported odor thresholds. Ozone reacts with certain alkenes to form a gas and aerosol phase of oxidation products, some of which are sensory irritants. However, all of the sensory irritating species have not yet been identified and whether the secondary aerosols (ultrafine and fine particles) contribute to sensory irritation requires investigation. Low relative humidity may exacerbate the sensory irritation impact. Practical Implications Certain odors, in addition to odor annoyance, may result in psychological effects and distraction from work. Some building materials continually cause perceivable odors, because the odor thresholds of the emitted compounds are low. Some oxidation products of alkenes (e.g. terpenes) may contribute to eye and airway symptoms under certain conditions and low relative humidity.

26 March 2004 in Environmental Science & Technology
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Journal Article
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PCPer Axel Clausen
Per Axel Clausen
VHVivi Hansen
Vivi Hansen
LGLars Gunnarsen
Lars Gunnarsen
AAAlireza Afshari
Alireza Afshari
PWPeder Wolkoff
Peder Wolkoff

1 June 2000 in Indoor Air
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Journal Article
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PWPeder Wolkoff
Peder Wolkoff
PCPer Axel Clausen
Per Axel Clausen
CWC. K. Wilkins
C. K. Wilkins
GNG. D. Nielsen
G. D. Nielsen
The American Society for Testing and Materials (ASTM) mouse bioassay, which quantifies airway irritation from reduction in the respiratory rate, was used to find evidence for the formation o...

19 February 2009 in Environmental Science & Technology
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Journal Article
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YXYing Xu
Ying Xu
EHElaine A. Cohen Hubal
Elaine A. Cohen Hubal
PCPer Axel Clausen
Per Axel Clausen
JLJohn C. Little
John C. Little

1 April 2004 in Indoor Air
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Journal Article
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AAA. Afshari
A. Afshari
LGLars Gunnarsen
Lars Gunnarsen
PCPer Axel Clausen
Per Axel Clausen
VHV. Hansen
V. Hansen
The main objective of this study was to generate quantitative and qualitative emission data on phthalates from different materials. To achieve this the existing (Chamber for Laboratory Investigations of Materials, Pollution and Air Quality) Climpaq-based procedure for simplified measurements of emissions of plasticizer from PVC and other plasticized materials was modified. It was applied to a range of products. Some of them were suspected of contributing to the indoor concentration of plasticizers. The emissions from PVC flooring, polyolefine flooring, a refrigerator list, two electric cables, PVC skirting and floor wax were studied in separate Climpaqs. The emission from the PVC flooring in the Climpaq was compared with results from the ultra-small chamber Field and Laboratory Emission Cell (FLEC). Sampling and analysis methods were optimized to measure plasticizers. Samples were taken in exhaust air from the chambers after 6, 35, 62, 105, and 150 days from the start of the experiment. PVC flooring was tested for an additional 100 days. Polyolefine covered with wax resulted in an air concentration of 22 microg/m3 of dibutylphthalate (DBP), which is two orders of magnitude larger than any other materials, but did not emit di(2-ethylhexyl)phthalate (DEHP). The other materials resulted in max concentration of approximately 1 microg/m3 of DEHP and low emissions of DBP. The concentration of DEHP in each chamber increased slowly to a rather stable level which was reached after 150 days. DBP concentrations in the chambers with PVC skirting, PVC flooring, polyolefine and floor wax reached their quasi-static equilibrium after 60 days. The modified method did not create sufficient data for the calculation of emission rates. Adsorption of emission on chamber surfaces made it impossible to use the first part of the experiment for emission rate calculation. When the concentration had stabilized, it was found to be almost identical and independent of chamber and ventilation rate. Emission rates were reduced at high concentrations probably because the concentration in the material was near equilibrium with the concentration in the chamber air.