Assessing Reasonable Worst-Case Full-Shift Exposure Levels from Data of Variable Quality

Abstract Stoffenmanager®v4.5 and Advanced REACH Tool (ART) v1.5, two higher tier exposure assessment tools for use under REACH, were evaluated by determining accuracy and robustness. A total of 282 exposure measurements from 51 exposure situations (ESs) were collected and categorized by exposure category. In this study, only the results of liquids with vapor pressure (VP) > 10 Pa category having a sufficient number of exposure measurements (n = 251 with 42 ESs) were utilized. In addition, the results were presented by handling/activity description and input parameters for the same exposure category. It should be noted that the performance results of Stoffenmanager and ART in this study cannot be directly compared for some ESs because ART allows a combination of up to four subtasks (and nonexposed periods) to be included, whereas the database for Stoffenmanager, separately developed under the permission of the legal owner of Stoffenmanager, permits the use of only one task to predict exposure estimates. Thus, it would be most appropriate to compare full-shift measurements against ART predictions (full shift including nonexposed periods) and task-based measurements against task-based Stoffenmanager predictions. For liquids with VP > 10 Pa category, Stoffenmanager®v4.5 appeared to be reasonably accurate and robust when predicting exposures [percentage of measurements exceeding the tool’s 90th percentile estimate (%M > T) was 15%]. Areas that could potentially be improved include ESs involving the task of handling of liquids on large surfaces or large work pieces, allocation of high and medium VP inputs, and absence of local exhaust ventilation input. Although the ART’s median predictions appeared to be reasonably accurate for liquids with VP > 10 Pa, the %M > T for the 90th percentile estimates was 41%, indicating that variance in exposure levels is underestimated by ART. The %M > T using the estimates of the upper value of 90% confidence interval (CI) of the 90th percentile estimate (UCI90) was considerably reduced to 18% for liquids with VP > 10 Pa. On the basis of this observation, users might be to consider using the upper limit value of 90% CI of the 90th percentile estimate for predicting reasonable worst case situations. Nevertheless, for some activities and input parameters, ART still shows areas to be improved. Hence, it is suggested that ART developers review the assumptions in relation to exposure variability within the tool, toward improving the tool performance in estimating percentile exposure levels. In addition, for both tools, only some handling/activity descriptions and input parameters were considered. Thus, further validation studies are still necessary.

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Does the Burning of Moxa (Artemisia vulgaris) in traditional Chinese medicine constitute a health hazard?

Acupuncture in Medicine ◽

10.1136/aim.2009.000422 ◽

2009 ◽

Vol 27 (1) ◽

pp. 16-20 ◽

Cited By ~ 32

Author(s):

John Wheeler ◽

Belinda Coppock ◽

Cecil Chen

Keyword(s):

Carbon Monoxide ◽

Chinese Medicine ◽

Traditional Chinese Medicine ◽

Health Hazard ◽

Urban Environments ◽

Operating Conditions ◽

Therapeutic Modality ◽

Worst Case ◽

Safety Standards ◽

Exposure Levels

Background Concerns have been expressed about potential toxicity of the smoke produced by the burning of moxa in traditional Chinese medicine. With the advent of strict anti-smoking legislation in the UK, it was decided to test the volatiles produced by moxibustion and compare them with current agreed safe exposure levels. Method Moxa, in the form of cigar shaped moxa “sticks” or “rolls”, was tested under International Organization for Standardization conditions in a tobacco testing laboratory, and the quantities of a number of pre-determined volatiles measured. The smoke tested was “sidestream smoke”, the smoke which arises from the burning tip of the moxa. The test results were then scaled up to reflect normal use and to provide direct comparisons with agreed national safety standards for both short- and long-term exposure levels. Results Levels of only two volatiles produced were equivalent or greater than the safe exposure levels, as was the carbon monoxide level reported, both as a consequence of using worst case assumptions for comparison. Under normal operating conditions neither volatile nor carbon monoxide would present a safety hazard. One group of chemicals tested, the aromatic amines, with known carcinogenic properties have no agreed safety levels. Results for these in the study compared favourably with background levels reported in urban environments. Conclusion There are no immediate concerns arising from the continued use of moxa as a therapeutic modality in traditional Chinese medicine. Further testing may be required to establish whether current recommendations for ventilation and cleansing of treatment room surfaces may need to be revised. Stronger recommendations may also be necessary on the inadvisability of using moxa on broken skin.

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Assessment of exposure determinants and exposure levels by using stationary concentration measurements and a probabilistic near-field/far-field exposure model

Open Research Europe ◽

10.12688/openreseurope.13752.1 ◽

2021 ◽

Vol 1 ◽

pp. 72

Author(s):

Antti Joonas Koivisto ◽

Andrea Spinazzè ◽

Frederik Verdonck ◽

Francesca Borghi ◽

Jakob Löndahl ◽

...

Keyword(s):

Near Field ◽

Exposure Model ◽

Exposure Level ◽

Far Field ◽

Worst Case ◽

Stationary Concentration ◽

Exposure Determinants ◽

Local Ventilation ◽

Exposure Levels ◽

The Impact

Background: The Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation requires the establishment of Conditions of Use (CoU) for all exposure scenarios to ensure good communication of safe working practices. Setting CoU requires the risk assessment of all relevant Contributing Scenarios (CSs) in the exposure scenario. A new CS has to be created whenever an Operational Condition (OC) is changed, resulting in an excessive number of exposure assessments. An efficient solution is to quantify OC concentrations and to identify reasonable worst-case scenarios with probabilistic exposure modeling. Methods: Here, we appoint CoU for powder pouring during the industrial manufacturing of a paint batch by quantifying OC exposure levels and exposure determinants. The quantification was performed by using stationary measurements and a probabilistic Near-Field/Far-Field (NF/FF) exposure model. Work shift and OC concentration levels were quantified for pouring TiO2 from big bags and small bags, pouring Micro Mica from small bags, and cleaning. The impact of exposure determinants on NF concentration level was quantified by (1) assessing exposure determinants correlation with the NF exposure level and (2) by performing simulations with different OCs. Results: Emission rate, air mixing between NF and FF and local ventilation were the most relevant exposure determinants affecting NF concentrations. Potentially risky OCs were identified by performing Reasonable Worst Case (RWC) simulations and by comparing the exposure 95th percentile distribution with 10% of the occupational exposure limit value (OELV). The CS was shown safe except in RWC scenario (ventilation rate from 0.4 to 1.6 1/h, 100 m3 room, no local ventilation, and NF ventilation of 1.6 m3/min). Conclusions: The CoU assessment was considered to comply with European Chemicals Agency (ECHA) legislation and EN 689 exposure assessment strategy for testing compliance with OEL values. One RWC scenario would require measurements since the exposure level was 12.5% of the OELV.

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Gefahrstoffbelastung auf dem Flughafenvorfeld – Teil 2: Gefahrstoffexpositionen/Hazardous substances on the airport apron – Part 2: hazardous substance exposure levels

Gefahrstoffe ◽

10.37544/0949-8036-2019-11-12-14 ◽

2019 ◽

Vol 79 (11-12) ◽

pp. 408-418

Author(s):

D. Breuer ◽

B. Flemming ◽

T. Sye ◽

S. Auras ◽

O. Heise ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Hazardous Substances ◽

Hazardous Substance ◽

Worst Case ◽

Substance Exposure ◽

Volatile Organic ◽

Exposure Levels

Flughäfen sind hochkomplexe Arbeitsbereiche mit vielfältigen Tätigkeiten und Gefährdungen. In Teil 1 dieser Veröffentlichung haben die Unfallversicherungsträger (UVT) 2018 die wesentlichen Arbeitsbereiche eines Flughafenvorfelds charakterisiert und mögliche Gefahrstoffbelastungen beschrieben. In diesem Teil werden nun Ergebnisse der am häufigsten gemessenen Gefahrstoffe Dieselrußemissionen, alveolengängige und einatembare Staubfraktion, Benzol, Kohlenwasserstoffgemische (Bewertung nach RCP), polycyclische aromatische Kohlenwasserstoffe und flüchtige organische Verbindungen (volatile organic compounds, VOC) zusammengestellt. Nicht selten erfolgten diese Messungen unter Worst-Case-Bedingungen, die Ergebnisse liegen in der Regel deutlich unter den Grenzwerten für Arbeitsplätze. Daher gehen die UVT davon aus, dass die Messwerte als gesundheitlich unbedenklich einzustufen sind. Weiterhin werden Messergebnisse zu ultrafeinen Partikeln vorgestellt. Diese Messungen fanden ebenfalls unter Worst-Case-Bedingungen statt, sodass die Mess- ergebnisse in der Regel höher sind als in bisherigen Studien. Die Unterschiede lassen sich durch die Messstrategie erklären. Darüber hinaus enthält dieser Artikel Erkenntnisse zum Biomonitoring bei Beschäftigten auf dem Flughafenvorfeld.

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Noise Exposure of School Teachers – Exposure Levels and Health Effects

Archives of Acoustics ◽

10.2478/aoa-2013-0031 ◽

2013 ◽

Vol 38 (2) ◽

pp. 259-264 ◽

Cited By ~ 1

Author(s):

Marija Hadzi-Nikolova ◽

Dejan Mirakovski ◽

Milka Zdravkovska ◽

Bistra Angelovska ◽

Nikolinka Doneva

Keyword(s):

High Schools ◽

Health Effects ◽

Noise Exposure ◽

Exposure Level ◽

Medical Sciences ◽

School Teachers ◽

Full Shift ◽

Exposure Levels ◽

Joint Study ◽

General School

Abstract Faculty of Natural and Technical Sciences and Faculty of Medical Sciences starting from December 2012, launched joint study in order to investigate personal noise exposure and associated health effects in general school teachers population, starting from kindergartens up to high schools in Stip, Macedonia. In order to determine workplace associated noise exposure and associated health effects in this specific profession, a full shift noise exposure of 40 teachers from 1 kindergarten, 2 primary and 2 high schools were measured in real conditions using noise dosimeters. A-weighted equivalent-continuous sound pressure levels (LAeq) of each teacher were recorded during single activities (classes). Normalized 8-hours exposure, termed the noise exposure level (Lex;8 h) was also computed. Daily noise dose is another descriptor for noise exposure that was determined as a measure of the total sound energy to which workers have been exposed, as a result of working in the varying noise levels. Health effects were assessed trough a full scale epidemiological study which included 231 teachers from the same schools. Specific questionnaire was used to extract information about subject’s perception on occupational noise exposure, as well as theirs occupational and medical history.

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A Systematic Review of Full-Shift, Noise Exposure Levels Among Construction Workers: Are We Improving?

Annals of Work Exposures and Health ◽

10.1093/annweh/wxy051 ◽

2018 ◽

Vol 62 (7) ◽

pp. 771-782 ◽

Cited By ~ 1

Author(s):

Kate Lewkowski ◽

Ian W Li ◽

Lin Fritschi ◽

Warwick Williams ◽

Jane S Heyworth

Keyword(s):

Systematic Review ◽

Noise Exposure ◽

Construction Workers ◽

Full Shift ◽

Exposure Levels

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Mosaic Mapping: A Means of Tiling Images to Shorten Acquisition Speed for Lower - Magnification SEM Images and Wavelength Dispersive Spectrometers (WDS) X-Ray Maps

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164659 ◽

1996 ◽

Vol 54 ◽

pp. 438-439

Author(s):

J.D. Geller ◽

C.R. Herrington

Keyword(s):

Limiting Factors ◽

X Rays ◽

Angular Range ◽

Acceptance Angle ◽

Sem Images ◽

Worst Case ◽

X Ray ◽

Focusing Distance ◽

Layered Crystals ◽

Working Distance

The minimum magnification for which an image can be acquired is determined by the design and implementation of the electron optical column and the scanning and display electronics. It is also a function of the working distance and, possibly, the accelerating voltage. For secondary and backscattered electron images there are usually no other limiting factors. However, for x-ray maps there are further considerations. The energy-dispersive x-ray spectrometers (EDS) have a much larger solid angle of detection that for WDS. They also do not suffer from Bragg’s Law focusing effects which limit the angular range and focusing distance from the diffracting crystal. In practical terms EDS maps can be acquired at the lowest magnification of the SEM, assuming the collimator does not cutoff the x-ray signal. For WDS the focusing properties of the crystal limits the angular range of acceptance of the incident x-radiation. The range is dependent upon the 2d spacing of the crystal, with the acceptance angle increasing with 2d spacing. The natural line width of the x-ray also plays a role. For the metal layered crystals used to diffract soft x-rays, such as Be - O, the minimum magnification is approximately 100X. In the worst case, for the LEF crystal which diffracts Ti - Zn, ˜1000X is the minimum.

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