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Tunga Salthammer - One of the best experts on this subject based on the ideXlab platform.

  • a permeation controlled formaldehyde reference source for application in environmental Test chambers
    Chemosphere, 2017
    Co-Authors: Tunga Salthammer, Ruth Giesen, Tobias Schripp
    Abstract:

    Abstract In a wide range of indoor air pollutants, formaldehyde is one of the most-used and best-known substances. In order to protect human health, many countries have established threshold values for the release of formaldehyde from miscellaneous products and revise them constantly. Compliance with these regulations is usually assessed by Emission Test chamber measurements or derived methods. To control and improve the mechanisms of an Emission Test chamber, a reliable reference source with sample mimicking Emission properties is required but not available so far. This study describes a permeation-controlled reference source based on the application of paraformaldehyde as formaldehyde releasing polymeric compound. Interactions between the formaldehyde release of the source and the governing chamber parameters temperature, relative humidity and air velocity were investigated in 1 m 3 Emission chambers. Depending on the conditions, constant formaldehyde concentrations between approximately 10 ppb and 150 ppb can be adjusted for up to 600 h. A linear correlation between the logarithm of the chamber concentration and the reciprocal temperature was found. The results support the feasibility of the source for validation of Emission Test chamber performance.

  • portable photocatalytic air cleaners efficiencies and by product generation
    Environmental Science and Pollution Research, 2016
    Co-Authors: Jan Gunschera, Doreen Markewitz, Birger Bansen, Tunga Salthammer, Hui Ding
    Abstract:

    Portable photocatalytic air cleaners were investigated in 24 and 48 m3 Emission Test chambers with regard to efficiency and by-product generation. For this purpose, formaldehyde, decane, 1,2-dichlorobenzene, toluene, α-pinene and heptanal were doped at sub-ppm concentration levels into the chambers individually and in mixtures. By way of specified Test protocols, efficiencies could be distinguished but were strongly dependant on the choice of Test compounds, especially on whether single or multi compound dosing was used, and on long-term effects. Initial clean air delivery rates (CADRs) up to 137 m3/h were measured. Typical by-products were found in significant concentrations. The main ones were formaldehyde up to 50 ppb (62 μg/m3) and acetone up to 80 ppb (190 μg/m3). Other aldehydes were also found, but at smaller levels. The detection of chloroacetone, a strong irritating compound, at concentrations up to 15 ppb (57 μg/m3) strengthens the importance of such investigations especially in cases were chloro-organic compounds are involved.

  • does e cigarette consumption cause passive vaping
    Indoor Air, 2013
    Co-Authors: Tobias Schripp, Doreen Markewitz, Erik Uhde, Tunga Salthammer
    Abstract:

    Electronic cigarette consumption (vaping) is marketed as an alterna- tive to conventional tobacco smoking. Technically, a mixture of chemicals containing carrier liquids, flavors, and optionally nicotine is vaporized and in- haled. The present study aims at the determination of the release of volatile organic compounds (VOC) and (ultra)fine particles (FP/UFP) from an e-ciga- rette under near-to-real-use conditions in an 8-m 3 Emission Test chamber. Fur- thermore, the inhaled mixture is analyzed in small chambers. An increase in FP/ UFP and VOC could be determined after the use of the e-cigarette. Prominent components in the gas-phase are 1,2-propanediol, 1,2,3-propanetriol, diacetin, flavorings, and traces of nicotine. As a consequence, passive vaping must be expected from the consumption of e-cigarettes. Furthermore, the inhaled aerosol undergoes changes in the human lung that is assumed to be attributed to deposition and evaporation.

  • evaluation of ultrafine particle Emissions from laser printers using Emission Test chambers
    Environmental Science & Technology, 2008
    Co-Authors: Tobias Schripp, Erik Uhde, Tunga Salthammer, Michael Wensing, Lidia Morawska
    Abstract:

    It has now been recognized that some hardcopy devices emit ultrafine particles (dp < 100 nm) during their operation. As a consequence, the time-dependent characterization of particle release from laser printers is of high interest in order to evaluate the exposure of office workers to such Emissions. The Emission profiles of different printers can be compared in Test chambers using a standardized Test protocol and measuring devices with high time resolution. The extraction of meaningful and comparable data from the obtained data set is a complex procedure due to the different Emission behavior patterns of the printers. The calculation of the unit specific Emission rate (SERu) is of limited use because the Emission profiles during the printing process ranged between short-term bursts and constant particle release. Therefore, other parameters such as the particle loss-rate coefficient, β, which provides information about the Testing conditions, and the area below the time vs concentration curve, F, which ch...

  • influence of molecular parameters on the sink effect in Test chambers
    Indoor Air, 2006
    Co-Authors: Erik Uhde, Tunga Salthammer
    Abstract:

    UNLABELLED The determination of the specific Emission rates of individual products and materials under indoor-related conditions requires the use of climate-controlled Emission Test chambers. However, most chambers demonstrate an inherent sink effect, i.e. the released components undergo adsorption/desorption processes with construction materials. Furthermore, this sink effect is enhanced by introducing an adsorbing sample surface into the Test chamber. The degree of adsorption, as well as the extent of the recovery, can vary significantly for different chambers and samples and also depends on the physical properties of the relevant substance. Whereas the sink effect caused by the chamber itself can be reduced by using appropriate construction materials, it is not possible to avoid the sink effect attributable to the actual sample. For this reason it is of importance to evaluate chambers and samples for possible sink effects, taking into consideration the physical properties of substances. This can be achieved by kinetic modeling of Emission data and determination of rate constants. The kinetic parameters obtained from curve fitting were combined with molecular parameters and applied to multivariate statistics. The properties of three different chambers with and without sink could be compared by cluster analysis. Principal component analysis revealed that the sink effect essentially depends on the boiling point of the substances examined. PRACTICAL IMPLICATIONS Emission Test chambers are operated by research institutions and Testing laboratories for different purposes. The determined Emission rate value of a building product is a function of the chamber construction, the material to be Tested and the molecular properties of the target compound. In this work it is demonstrated, which parameters have the main influence on the Test result. Furthermore it is shown how multivariate statistical analysis can be applied to experimental data to characterize the sink effect under dynamic conditions. This new technique provides a suitable tool for the evaluation and comparison of Test chambers.

Rudolf Probst - One of the best experts on this subject based on the ideXlab platform.

Erik Uhde - One of the best experts on this subject based on the ideXlab platform.

  • does e cigarette consumption cause passive vaping
    Indoor Air, 2013
    Co-Authors: Tobias Schripp, Doreen Markewitz, Erik Uhde, Tunga Salthammer
    Abstract:

    Electronic cigarette consumption (vaping) is marketed as an alterna- tive to conventional tobacco smoking. Technically, a mixture of chemicals containing carrier liquids, flavors, and optionally nicotine is vaporized and in- haled. The present study aims at the determination of the release of volatile organic compounds (VOC) and (ultra)fine particles (FP/UFP) from an e-ciga- rette under near-to-real-use conditions in an 8-m 3 Emission Test chamber. Fur- thermore, the inhaled mixture is analyzed in small chambers. An increase in FP/ UFP and VOC could be determined after the use of the e-cigarette. Prominent components in the gas-phase are 1,2-propanediol, 1,2,3-propanetriol, diacetin, flavorings, and traces of nicotine. As a consequence, passive vaping must be expected from the consumption of e-cigarettes. Furthermore, the inhaled aerosol undergoes changes in the human lung that is assumed to be attributed to deposition and evaporation.

  • evaluation of ultrafine particle Emissions from laser printers using Emission Test chambers
    Environmental Science & Technology, 2008
    Co-Authors: Tobias Schripp, Erik Uhde, Tunga Salthammer, Michael Wensing, Lidia Morawska
    Abstract:

    It has now been recognized that some hardcopy devices emit ultrafine particles (dp < 100 nm) during their operation. As a consequence, the time-dependent characterization of particle release from laser printers is of high interest in order to evaluate the exposure of office workers to such Emissions. The Emission profiles of different printers can be compared in Test chambers using a standardized Test protocol and measuring devices with high time resolution. The extraction of meaningful and comparable data from the obtained data set is a complex procedure due to the different Emission behavior patterns of the printers. The calculation of the unit specific Emission rate (SERu) is of limited use because the Emission profiles during the printing process ranged between short-term bursts and constant particle release. Therefore, other parameters such as the particle loss-rate coefficient, β, which provides information about the Testing conditions, and the area below the time vs concentration curve, F, which ch...

  • influence of molecular parameters on the sink effect in Test chambers
    Indoor Air, 2006
    Co-Authors: Erik Uhde, Tunga Salthammer
    Abstract:

    UNLABELLED The determination of the specific Emission rates of individual products and materials under indoor-related conditions requires the use of climate-controlled Emission Test chambers. However, most chambers demonstrate an inherent sink effect, i.e. the released components undergo adsorption/desorption processes with construction materials. Furthermore, this sink effect is enhanced by introducing an adsorbing sample surface into the Test chamber. The degree of adsorption, as well as the extent of the recovery, can vary significantly for different chambers and samples and also depends on the physical properties of the relevant substance. Whereas the sink effect caused by the chamber itself can be reduced by using appropriate construction materials, it is not possible to avoid the sink effect attributable to the actual sample. For this reason it is of importance to evaluate chambers and samples for possible sink effects, taking into consideration the physical properties of substances. This can be achieved by kinetic modeling of Emission data and determination of rate constants. The kinetic parameters obtained from curve fitting were combined with molecular parameters and applied to multivariate statistics. The properties of three different chambers with and without sink could be compared by cluster analysis. Principal component analysis revealed that the sink effect essentially depends on the boiling point of the substances examined. PRACTICAL IMPLICATIONS Emission Test chambers are operated by research institutions and Testing laboratories for different purposes. The determined Emission rate value of a building product is a function of the chamber construction, the material to be Tested and the molecular properties of the target compound. In this work it is demonstrated, which parameters have the main influence on the Test result. Furthermore it is shown how multivariate statistical analysis can be applied to experimental data to characterize the sink effect under dynamic conditions. This new technique provides a suitable tool for the evaluation and comparison of Test chambers.

  • Phthalic esters in the indoor environment-Test chamber studies on PVC-coated wallcoverings.
    Indoor air, 2001
    Co-Authors: Erik Uhde, Maria Bednarek, Ferdinand Fuhrmann, Tunga Salthammer
    Abstract:

    Phthalic acid esters are important additives in polyvinyl chloride (PVC) products. Since PVC plastisoles for the production of wallcoverings contain about 30% phthalic acid esters, it is a crucial question whether these products can contribute to the pollution of the indoor environment. In this study, the Emission of several technically relevant phthalates from PVC-coated wallcoverings were measured in Emission Test chambers under standard room conditions. During a 14-day Test period, both the chamber air concentrations and the condensation on a cooled plate (fogging) were determined. In the chamber air, maximum concentrations of 5.1 micrograms/m3 for di-n-butylphthalate (DBP), 2.08 micrograms/m3 for di-pentylphthalate (DPP) and 0.94 microgram/m3 for di-(2-ethylhexyl)phthalate (DEHP) were found. After 14 days of exposure, up to 60.4 micrograms DEHP and 17.7 micrograms DPP could be quantified on the cooled plates of the fogging apparatus. The amounts of DBP and DIBP were significantly lower. A simple exposure calculation indicated no specific risk of an increased phthalate exposure in rooms with PVC wallcoverings.

Tobias Schripp - One of the best experts on this subject based on the ideXlab platform.

  • a permeation controlled formaldehyde reference source for application in environmental Test chambers
    Chemosphere, 2017
    Co-Authors: Tunga Salthammer, Ruth Giesen, Tobias Schripp
    Abstract:

    Abstract In a wide range of indoor air pollutants, formaldehyde is one of the most-used and best-known substances. In order to protect human health, many countries have established threshold values for the release of formaldehyde from miscellaneous products and revise them constantly. Compliance with these regulations is usually assessed by Emission Test chamber measurements or derived methods. To control and improve the mechanisms of an Emission Test chamber, a reliable reference source with sample mimicking Emission properties is required but not available so far. This study describes a permeation-controlled reference source based on the application of paraformaldehyde as formaldehyde releasing polymeric compound. Interactions between the formaldehyde release of the source and the governing chamber parameters temperature, relative humidity and air velocity were investigated in 1 m 3 Emission chambers. Depending on the conditions, constant formaldehyde concentrations between approximately 10 ppb and 150 ppb can be adjusted for up to 600 h. A linear correlation between the logarithm of the chamber concentration and the reciprocal temperature was found. The results support the feasibility of the source for validation of Emission Test chamber performance.

  • does e cigarette consumption cause passive vaping
    Indoor Air, 2013
    Co-Authors: Tobias Schripp, Doreen Markewitz, Erik Uhde, Tunga Salthammer
    Abstract:

    Electronic cigarette consumption (vaping) is marketed as an alterna- tive to conventional tobacco smoking. Technically, a mixture of chemicals containing carrier liquids, flavors, and optionally nicotine is vaporized and in- haled. The present study aims at the determination of the release of volatile organic compounds (VOC) and (ultra)fine particles (FP/UFP) from an e-ciga- rette under near-to-real-use conditions in an 8-m 3 Emission Test chamber. Fur- thermore, the inhaled mixture is analyzed in small chambers. An increase in FP/ UFP and VOC could be determined after the use of the e-cigarette. Prominent components in the gas-phase are 1,2-propanediol, 1,2,3-propanetriol, diacetin, flavorings, and traces of nicotine. As a consequence, passive vaping must be expected from the consumption of e-cigarettes. Furthermore, the inhaled aerosol undergoes changes in the human lung that is assumed to be attributed to deposition and evaporation.

  • evaluation of ultrafine particle Emissions from laser printers using Emission Test chambers
    Environmental Science & Technology, 2008
    Co-Authors: Tobias Schripp, Erik Uhde, Tunga Salthammer, Michael Wensing, Lidia Morawska
    Abstract:

    It has now been recognized that some hardcopy devices emit ultrafine particles (dp < 100 nm) during their operation. As a consequence, the time-dependent characterization of particle release from laser printers is of high interest in order to evaluate the exposure of office workers to such Emissions. The Emission profiles of different printers can be compared in Test chambers using a standardized Test protocol and measuring devices with high time resolution. The extraction of meaningful and comparable data from the obtained data set is a complex procedure due to the different Emission behavior patterns of the printers. The calculation of the unit specific Emission rate (SERu) is of limited use because the Emission profiles during the printing process ranged between short-term bursts and constant particle release. Therefore, other parameters such as the particle loss-rate coefficient, β, which provides information about the Testing conditions, and the area below the time vs concentration curve, F, which ch...

Michael P Gorga - One of the best experts on this subject based on the ideXlab platform.

  • do optimal conditions improve distortion product otoacoustic Emission Test performance
    Ear and Hearing, 2011
    Co-Authors: Benjamin Kirby, Judy G Kopun, Stephen T Neely, Michael P Gorga
    Abstract:

    Objectives: To determine whether an “optimal” distortion product otoacoustic Emission (DPOAE) protocol that (1) used optimal stimulus levels and primary-frequency ratios for each f2, (2) simultaneously measured 2f2 f1 and 2f1 f2 distortion products, (3) controlled source contribution, (4) implemented improved calibration techniques, (5) accounted for the influence of middle ear reflectance, and (6) applied multivariate analyses to DPOAE data results in improved accuracy in differentiating between normal-hearing and hearing-impaired ears, compared with a standard clinical protocol. Design: Data were collected for f2 frequencies ranging from 0.75 to 8 kHz in 28 normal-hearing and 78 hearing-impaired subjects. The protocol included a control condition incorporating standard stimulus levels and primary-frequency ratios calibrated with a standard SPL method and three experimental conditions using optimized stimuli calibrated with an alternative forward pressure level method. The experimental conditions differed with respect to the level of the reflection-source suppressor tone and included conditions referred to as the null suppressor (i.e., no suppressor tone presented), low-level suppressor (i.e., suppressor tone presented at 58 dB SPL), and high-level suppressor (i.e., suppressor tone presented at 68 dB SPL) conditions. The area under receiver operating characteristic (AROC) curves and sensitivities for fixed specificities (and vice versa) were estimated to evaluate Test performance in each condition. Results: AROC analyses indicated (1) improved Test performance in all conditions using multivariate analyses, (2) improved performance in the null suppressor and low suppressor experimental conditions compared with the control condition, and (3) poorer performance below 4 kHz with the high-level suppressor. As expected from AROC, sensitivities for fixed specificities and specificities for fixed sensitivities were highest for the null suppressor and low suppressor conditions and lowest for standard clinical procedures. The influence of 2f2 f1 and reflectance on Test performance were negligible. Conclusions: Predictions of auditory status based on DPOAE measurements in clinical protocols may be improved by the inclusion of (1) optimized stimuli, (2) alternative calibration techniques, (3) low-level suppressors, and (4) multivariate analyses. (Ear & Hearing 2010;31;1–●)

  • distortion product otoacoustic Emission Test performance when both 2 f1 f2 and 2 f2 f1 are used to predict auditory status
    Journal of the Acoustical Society of America, 2000
    Co-Authors: Michael P Gorga, Patricia A Dorn, Kimberly Nelson, Thomas Davis, Stephen T Neely
    Abstract:

    The objective of this study was to determine whether distortion product otoacoustic Emission (DPOAE) Test performance, defined as its ability to distinguish normal-hearing ears from those with hearing loss, can be improved by examining response and noise amplitudes at 2 f1–f2 and 2 f2–f1 simultaneously. In addition, there was interest in knowing whether measurements at both DPs and for several primary frequency pairs can be used in a multivariate analysis to further optimize Test performance. DPOAE and noise amplitudes were measured at 2 f1–f2 and 2 f2–f1 for 12 primary levels (L2 from 10 to 65 dB SPL in 5-dB steps) and 9 pairs of primary frequencies (0.5 to 8 kHz in 1/2-octave steps). All data were collected in a sound-treated room from 70 subjects with normal hearing and 80 subjects with hearing loss. Subjects had normal middle-ear function at the time of the DPOAE Test, based on standard tympanometric measurements. Measurement-based stopping rules were used such that the Test terminated when the noise ...

  • distortion product otoacoustic Emission Test performance for a priori criteria and for multifrequency audiometric standards
    Ear and Hearing, 1999
    Co-Authors: Michael P Gorga, Stephen T Neely, Patricia A Dorn
    Abstract:

    Objectives: 1) To describe distortion product otoacoustic Emission (DPOAE) Test performance when a priori response criteria are applied to a large set of DPOAE data. 2) To describe DPOAE Test performance when multifrequency definitions of auditory function are used. 3) To determine DPOAE Test performance when a single decision regarding auditory status is made for an ear, based on DPOAE data from several frequencies. 4) To compare univariate and multivariate Test performance when multifrequency gold standard definitions and response criteria are applied to DPOAE data. Design: DPOAE and audiometric data were analyzed from 1267 ears of 806 subjects. These data were evaluated for three different frequency combinations (2, 3, 4 kHz; 2, 3, 4, 6 kHz; 1.5, 2, 3, 4, 6 kHz). DPOAE data were collected for each of the f 2 frequencies listed above, using primary levels (L 1 /L 2 ) of 65/55 dB SPL and a primary ratio (f 2 /f 1 ) of 1.22. Sensitivity and specificity were evaluated for signal to noise ratios (SNRs) of 3, 6, and 9 dB, which are in common clinical use. In addition, Test performance was evaluated using clinical decision theory, following the convention we have used in previous reports on otoacoustic Emission Test performance. Both univariate and multivariate analyses techniques were applied to the data. In addition to evaluating DPOAE Test performance for the case when audiometric and f 2 frequency were equal, multifrequency gold standards and multifrequency criterion responses were evaluated. Three new gold standards were used to assess Test performance: average pure-tone thresholds, extrema thresholds that took into account both the magnitude of the loss and the number of frequencies at which hearing loss existed, and a combination of the two. These new gold standards were applied to each of the three frequency groups described above. Results: As expected, SNR criteria of 3, 6, and 9 dB never resulted in perfect DPOAE Test performance. Even the most stringent of these criteria (9 dB SNR) did not result in a sensitivity of 100%. This result suggests that caution should be exercised in the interpretation of DPOAE Test results when these a priori criteria are used clinically. Excellent Test performance was achieved when auditory status was classified on the basis of the new gold standards and when either SNR or the output of multivariate logistic regressions (LRs) were used as criterion measures. Invariably, the LR resulted in superior Test performance compared with what was achieved by the SNR. For SNR criteria of 3, 6, and 9 dB and (by definition) for the LR, specificity, in general, exceeded 80% and often was greater than 90%. Sensitivity, however, depended on the magnitude of hearing loss. Diagnostic errors, when they occurred, were more common for patients with mild hearing losses (21 to 40 dB HL); sensitivity approached 100% once the hearing loss exceeded 40 dB HL. The largest differences between Test performance based on SNR or LR occurred for the ears with mild hearing loss, where the LR resulted in more accurate diagnoses. Conclusions: It should not be assumed that the use of a priori response criteria, such as SNRs of 3, 6, or 9 dB, will identify all ears with hearing loss. Test performance when multifrequency gold standards are used to define an ear as normal or impaired and when data from multiple f 2 frequencies are used to make a diagnosis, resulted in excellent Test performance, especially when the LR was used. When predicting auditory status with multifrequency gold standards, the LR resulted in relative operating characteristic curve areas of 0.95 or 0.96. An output from the LR can be selected that results in a specificity of 90% or better. When the loss exceeded 40 dB HL, the same output from the LR resulted in Test sensitivity of nearly 100%. These were the best Test results that were achieved. An algorithm based on the LR (when DPOAE and noise amplitudes at three, four, or five frequencies are used as inputs) mig