Effect Of Local Exhaust Ventilation Research Articles

39 Systematic Review of Validation Studies of the ECETOC Targeted Risk Assessment V3 Tool for Worker Exposure Estimation Under Reach

Abstract The Targeted Risk Assessment tool (TRA) has been widely used since 2010 in the development of REACH registration dossiers for classified chemical substances to estimate worker exposures (inhalation, dermal) across manufacturing and use operations in supply chains in Europe. The TRA is a Tier-1 tool which produces simplified exposure predictions based on limited inputs and intended to be conservative. The current version (3.1) of the TRA was released in 2012 and has been built into ECHA’s CHESAR tool. A number of studies have been published of TRA-generated exposure predictions compared with workplace measurement data and presenting conclusions about the tool performance. Most publications covered only a subset of the tool outputs. A group of ECETOC exposure assessors assembled inventories of published comparisons over the period of 2010-2020 (approximately 120 workplace scenarios for long-term inhalation, 40 scenarios for peak inhalation and 80 scenarios for dermal exposure) to systematically review the tool performance. The analysis has allowed to draw more robust conclusions about the performance of specific aspects of the tool, such as base level estimates and effectiveness of local exhaust ventilation, to either reinforce the conclusions of conservatism (majority of scenarios) or recommend changes to tool settings in a future version (minority of cases) to better match the tool’s intent. A short overview of the comparisons will be presented, as well as the planned changes to the tool settings.

HBM4EU Chromates Study: Determinants of Exposure to Hexavalent Chromium in Plating, Welding and Other Occupational Settings.

Work-related exposures in industrial processing of chromate (chrome plating, surface treatment and welding) raise concern regarding the health risk of hexavalent chromium (Cr(VI)). In this study, performed under the HBM4EU project, we focused on better understanding the determinants of exposure and recognising how risk management measures (RMMs) contribute to a reduction in exposure. HBM and occupational hygiene data were collected from 399 workers and 203 controls recruited in nine European countries. Urinary total chromium (U-Cr), personal inhalable and respirable dust of Cr and Cr(VI) and Cr from hand wipes were collected. Data on the RMMs were collected by questionnaires. We studied the association between different exposure parameters and the use of RMMs. The relationship between exposure by inhalation and U-Cr in different worker groups was analysed using regression analysis and found a strong association. Automatisation of Cr electroplating dipping explained lower exposure levels in platers. The use of personal protective equipment resulted in lower U-Cr levels in welding, bath plating and painting. An effect of wearing gloves was observed in machining. An effect of local exhaust ventilation and training was observed in welding. Regression analyses showed that in platers, exposure to air level of 5 µg/m3 corresponds to U-Cr level of 7 µg/g creatinine. In welders, the same inhalation exposure resulted in lower U-Cr levels reflecting toxicokinetic differences of different chromium species.

Simulation on the effect of local exhaust ventilation in removing surgical smoke

The indoor environment of the operating room has a significant impact on the health of personnel. Compared with the pollutants released from occupants, the amount of pollutants generated by surgical equipment is greater, which easily affects the health of patients and doctors. In this study, local exhaust ventilation (LEV) is applied to an operating room and LEV is mounted near the operation zone to remove the surgical smoke from the surgical equipment. CFD technique is used and the surgical smoke concentration reduction potential under different inlet air volumes and different inlet areas of LEV is studied. The results show that compared with the traditional method, when the inlet area of each LEV is set to 0.030 m2, the surgical smoke concentration can be reduced by 10.8%-39.2% as the inlet air volume increases from 0.003 to 0.027 m3/s; when the inlet air volume of each LEV is set to 0.015 m3/s, the surgical smoke concentration can be reduced by 24.7%-31.6% as the inlet area varies from 0.015 to 0.060 m2. This study shows that the LEV has a good potential in reducing surgical smoke concentration in the operating room. Keywords: operating room, local exhaust ventilation, laminar airflow, surgical smoke, CFD

Benzene Exposure on Rig X from Drilling Fluid and Effectiveness of Local Exhaust Ventilation

Introduction: Benzene is a carcinogenic compound commonly found in drilling fluid, a chemical used in oil and gas drilling operations. Benzene exposure to workers is known to cause acute and/or chronic disease. Adequate control measures shall be identified and implemented to prevent the adverse health effects of benzene from the utilization of drilling fluid. Methods: This study measured benzene concentrations at several locations, above the drilling rig, which has the potential risk of benzene vapor exposure. From the measurement results, if the threshold limit value was exceeded, LEV was proposed to be installed and the effectiveness of LEV at each location would be assessed. A two-tailed t-test was used with a confidence level of 95% (α=0.05) to measure the effectiveness of LEV. Results: In several areas, benzene concentration exceeded TLV-TWA, and LEV was installed in those areas as control measures. In this study, it was found that LEV was not always effective in reducing the concentration of benzene in some areas. Conclusion: Drilling fluid was essential for drilling activity, and this could cause benzene vapor to contaminate the working area. The installation of the LEV shall consider the type of containment through which the drilling fluid flows to ensure the mitigation measures are effective to reduce the concentration of benzene in the air that may be exposed to workers.Keywords: benzene, drilling fluid, exhaust ventilation

Control of Dust Dispersion From an Enclosed Renovation Site Into Adjacent Areas by Using Local Exhaust Ventilation.

In real-world applications, implementation of an enclosure and negative pressurization is not always adequate to prevent the dispersion of dust from renovation sites. This study aimed to quantify the effect of local exhaust ventilation (LEV) in controlling the dust concentration within an enclosed renovation site to reduce the dust dispersion into adjacent areas. The concentrations of inhalable and respirable dust were measured in 16 cases during renovation projects. Filter samples and time-resolved dust concentration data were collected simultaneously from the renovation site and adjacent areas to assess the efficacy of LEV in limiting the dust dispersion. The dispersion of dust outside of the enclosed renovation sites was limited significantly with using LEV. The estimated dust removal efficiency of LEV was 79% for inhalable dust concentration in the renovation site and 62% in the adjacent area. The use of LEV reduced the concentration of respirable dust by 33‒90% in the adjacent area and 80-87% within the renovation site. Using LEV was found to play a substantial role in dust containment, particularly when the enclosure failed to maintain the negative pressure. The study provides data-driven recommendations that are of practical importance as they promote healthier workplaces and policy improvements. In conclusion, dust dispersion into adjacent areas is prevented with an airtight enclosure (including airlocks) and continuous negative pressure. Dust containment was also obtained by having target dust concentration at the enclosed renovation site to below 4 mg m-3 for inhalable dust and below 1 mg m-3 for respirable dust, even though the enclosures not being continuously under negative pressure. The suggested target concentrations are achievable by using on-tool LEV during the most dust-producing tasks.

Inhalation exposure during spray application and subsequent sanding of a wood sealant containing zinc oxide nanoparticles

ABSTRACTNano-enabled construction products have entered into commerce. There are concerns about the safety of manufactured nanomaterials, and exposure assessments are needed for a more complete understanding of risk. This study assessed potential inhalation exposure to ZnO nanoparticles during spray application and power sanding of a commercially available wood sealant and evaluated the effectiveness of local exhaust ventilation in reducing exposure. A tradesperson performed the spraying and sanding inside an environmentally-controlled chamber. Dust control methods during sanding were compared. Filter-based sampling, electron microscopy, and real-time particle counters provided measures of exposure. Airborne nanoparticles above background levels were detected by particle counters for all exposure scenarios. Nanoparticle number concentrations and particle size distributions were similar for sanding of treated versus untreated wood. Very few unbound nanoparticles were detected in aerosol samples via electron microscopy, rather nano-sized ZnO was contained within, or on the surface of larger airborne particles. Whether the presence of nanoscale ZnO in these aerosols affects toxicity merits further investigation. Mass-based exposure measurements were below the NIOSH Recommended Exposure Limit for Zn, although there are no established exposure limits for nanoscale ZnO. Local exhaust ventilation was effective, reducing airborne nanoparticle number concentrations by up to 92% and reducing personal exposure to total dust by at least 80% in terms of mass. Given the discrepancies between the particle count data and electron microscopy observations, the chemical identity of the airborne nanoparticles detected by the particle counters remains uncertain. Prior studies attributed the main source of nanoparticle emissions during sanding to copper nanoparticles generated from electric sander motors. Potentially contrary results are presented suggesting the sander motor may not have been the primary source of nanoparticle emissions in this study. Further research is needed to understand potential risks faced by construction workers exposed to mixed aerosols containing manufactured nanomaterials. Until these risks are better understood, this study demonstrates that engineering controls can reduce exposure to manufactured nanomaterials; doing so may be prudent for protecting worker health.

Evaluation of a Dust Control for a Small Slab-Riding Dowel Drill for Concrete Pavement.

To assess the effectiveness of local exhaust ventilation to control respirable crystalline silica exposures to acceptable levels during concrete dowel drilling. Personal breathing zone samples for respirable dust and crystalline silica were collected while laborers drilled holes 3.5 cm diameter by 36 cm deep in a concrete slab using a single-drill slab-riding dowel drill equipped with local exhaust ventilation. Data were collected on air flow, weather, and productivity. All respirable dust samples were below the 90 µg detection limit which, when combined with the largest sample volume, resulted in a minimum detectable concentration of 0.31 mg m(-3). This occurred in a 32-min sample collected when 27 holes were drilled. Quartz was only detected in one air sample; 0.09 mg m(-3) of quartz was found on an 8-min sample collected during a drill maintenance task. The minimum detectable concentration for quartz in personal air samples collected while drilling was performed was 0.02 mg m(-3). The average number of holes drilled during each drilling sample was 23. Over the course of the 2-day study, air flow measured at the dust collector decreased from 2.2 to 1.7 m(3) s(-1). The dust control performed well under the conditions of this test. The initial duct velocity with a clean filter was sufficient to prevent settling, but gradually fell below the recommended value to prevent dust from settling in the duct. The practice of raising the drill between each hole may have prevented the dust from settling in the duct. A slightly higher flow rate and an improved duct design would prevent settling without regard to the position of the drill.

Chemical exposure in hairdresser salons: Effect of local exhaust ventilation

Although several studies demonstrate adverse health effects among hairdressers that may be related to their working environment, relatively few studies have described the chemical exposure levels in hairdresser salons. This paper shows the exposure level of isopropanol, ethanol, toluene, phenylendiamines, diaminotoluene and ammonia in six hairdresser salons, and the effect of local exhaust ventilation on these exposure levels.Stationary measurements were performed at the mixing location in the hairdresser salons. At this location isopropanol was found to be in the range from 0.7–15 mg/m3, ethanol in the range from 4–36 mg/m3 and toluene from 0.04-0.11 mg/m3. The range of ammonia in the same area was from 0.1-1.2 mg/m3.Personal monitoring of the hairdresser showed an exposure level of ammonia in a range from 0.3–10 mg/m3. Phenylendiamines and diaminotoluene were not detected.The exposure level was significantly lower in the salons with local exhaust ventilation than in the salons with no ventilation.

Chemical Exposure in Hairdresser Salons: Effect of Local Exhaust Ventilation

Although several studies demonstrate adverse health effects among hairdressers that may be related to their working environment, relatively few studies have described the chemical exposure levels in hairdresser salons. This paper shows the exposure level of isopropanol, ethanol, toluene, phenylendiamines, diaminotoluene and ammonia in six hairdresser salons, and the effect of local exhaust ventilation on these exposure levels. Stationary measurements were performed at the mixing location in the hairdresser salons. At this location isopropanol was found to be in the range from 0.7-15 mg/m3, ethanol in the range from 4-36 mg/m3 and toluene from 0.04-0.11 mg/m3. The range of ammonia in the same area was from 0.1-1.2 mg/m3. Personal monitoring of the hairdresser showed an exposure level of ammonia in a range from 0.3-10 mg/m3. Phenylendiamines and diaminotoluene were not detected. The exposure level was significantly lower in the salons with local exhaust ventilation than in the salons with no ventilation.