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ABSTRACT: Reports profiling airborne particulate matter (PM) in farm fields, especially during a Class B biosolids land-injection process, are scarce. Thus, this study characterized PM in such a farm field located in northwest Ohio. For comparison, a control farm field with no biosolids application history was also monitored. During 11 days of varied agricultural activities, the concentrations of particle mass and number (count) and also metal content were monitored in the study field, and their interactions with environmental factors were examined. The monitoring was performed across the farm field at four heights of 0.5, 1.5, 2.5, and 3.5 m from the ground. The overall mean (SD) concentration (μg/m(3)) of respirable suspended particulate matter (RPM) was 30.8 (23.1) with means ranging from 15.9 (3.80) during post-tilling Event 1, 19.9 (12.4) during biosolids application to 56.1 (11.7) during post-harvest (including baling) activity. The maximum concentration of RPM (μg/m(3)) was 43 during biosolids application, 90 during post-harvest, and 183 during post-tilling Event 2 activities. Overall, 93.7% (8.98%) of the total suspended particulate matter (TPM) was respirable. The levels of RPM significantly (p < 0.01) correlated with TPM and particle counts of ultrafine particles (UFP) and 0.3 μm particle size. Ambient temperature showed no effect, whereas wind speed and relative humidity had an inverse effect on RPM concentration. Particle concentrations changed minimally during each set of monitoring across the field, except during major activities or sudden weather changes. For particles with sizes of 2, 5, and 10 μm, the counts decreased with increasing height from the ground and were significantly (p < 0.05) higher at 0.5 m than at other heights. The levels of nine metals within particles monitored were well below current recommended occupational exposure criteria. These results suggest that injection of the biosolids into agricultural land provides significant protection against exposure to biosolids particles.
Journal of Occupational and Environmental Hygiene 08/2012; 9(8):502-16. · 1.19 Impact Factor
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ABSTRACT: Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m³ using 100-125 mm (4-5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100-125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the recommended criterion of 0.025 mg/m³ for crystalline silica, requiring further refinement in engineering controls, administrative controls, or the use of respirators.
Journal of Occupational and Environmental Hygiene 12/2010; 7(12):700-11. · 1.19 Impact Factor
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ABSTRACT: The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.
Journal of Occupational and Environmental Hygiene 11/2007; 4(10):770-9. · 1.19 Impact Factor
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ABSTRACT: Indoor air quality in restaurants was studied in two cities in northwest Ohio after clean indoor air ordinances had been enacted. Carbon dioxide and ultrafine particles were measured in two restaurants in Toledo and two restaurants in Bowling Green. One restaurant in each city was smoke free, and one restaurant in each city contained a dedicated smoking room. A smoke free office space was also assessed as a reference site. Measurements were collected with datalogging instrumentation simultaneously in both the designated smoking room, if present, and in the nonsmoking section. For smoke free establishments, datalogging instrumentation was also used. Carbon dioxide levels were elevated in all four restaurants, with only 32% of the measurements meeting the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) criterion level of 1000 ppm. Ultrafine particles currently do not have any formal standard or guideline. Statistically significant differences were evident between all four restaurants and the reference site. The largest differences were found between the two designated smoking rooms and the reference site (p < 0.001), with the mean levels in the smoking rooms up to 43 times higher than in the reference site. The results from this study indicate inadequate fresh air supply in all four restaurants, particularly in the designated smoking rooms, and the possibility that the designated smoking rooms were not containing the environment tobacco smoke, based on the ultrafine particle concentrations measured in the nonsmoking areas of the smoking restaurants.
Journal of Occupational and Environmental Hygiene 05/2007; 4(4):246-52. · 1.19 Impact Factor
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ABSTRACT: UV-transilluminators use ultraviolet radiation (UVR) to visualize proteins, DNA, RNA, and their precursors in a gel electrophoresis procedure. This study was initiated to evaluate workers' exposure to UVR during their use of UV-transilluminators. The levels of irradiance of UV-A, UV-B, and UV-C were determined for 29 UV-transilluminators at arbitrary measuring locations of 6, 25, 62, and 125 cm from the center of the UV-transilluminator's filter surface in the direction of the operator's head. The operators (faculty, research staff, and graduate students) worked within 62 cm of the transilluminators, with most subjects commonly working at < or =25 cm from the UV-transilluminator's filter surface. Daily exposure time ranged from 1 to 60 min. Actinic hazard (effective irradiance level of UVR) was also determined for three representative UV-transilluminators at arbitrary measuring locations of 2.5, 5, 10, 15, 20, 30, 40, and 50 cm from these sets' filter surface in the direction of the operator's head. The allowable exposure time for these instruments was less than 20 sec within 15 cm, less than 35 sec within 25 cm, and less than 2 min within 50 cm from the UV-transilluminators' filter surface. The results of this study suggest that the use of UV-transilluminators exposes operators to levels of UVR in excess of exposure guidelines. It is recommended that special safety training be provided for the affected employees and that exposure should be controlled by one or the combination of automation, substitution, isolation, posted warning signs, shielding, and/or personal protective equipment.
Journal of Occupational and Environmental Hygiene 11/2005; 2(10):493-6. · 1.19 Impact Factor
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ABSTRACT: Clean indoor air (CIA) ordinances in Toledo, Ohio, and Bowling Green, Ohio, regulate smoking in restaurants to protect patrons and employees. Yet complete protection is questionable because the ordinances allow for smoking in certain dining sections. Two restaurants were studied in each city, one smoking and one nonsmoking. Levels of contaminants related to environmental tobacco smoke (ETS)--determined by personal and area air monitoring-in the nonsmoking restaurants were comparable to levels in a control environment. However, levels of ETS-related contaminants in the smoking restaurants, including designated nonsmoking sections, were significantly higher than levels in the control environment. ETS-related contamination of the nonsmoking sections in the smoking restaurants is attributable to direct openings between the smoking and nonsmoking sections. Reasonable protection of employees and patrons against ETS-related contaminants requires strict enforcement of CIA ordinances. Full protection is achievable only with 100% smoke-free policies.
Archives of Environmental Health An International Journal 01/2005; 59(12):677-85.
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ABSTRACT: Engineering or administrative methods are often insufficient or impractical to control exposure to chemicals in anatomy laboratories. This study explored the feasibility of wearing one or a combination of respirators and goggles used as personal protective equipment (PPE) to control exposure in one such laboratory.
A group of 28 subjects were briefly trained in wearing PPE, fit-tested, and asked to complete a questionnaire regarding their subjective reaction after wearing the assigned PPE ensemble while working in the laboratory. The subjects' exposure to formaldehyde was also measured and generally exceeded the recommended limits.
When a full-face respirator or the combination of a half-mask respirator and goggles was worn, a majority of subjects reported no odor problem and no irritation to eyes or upper respiratory system. Subjects accepted the PPE to certain degrees, but those using respirators encountered difficulties communicating with others.
The combination of a half-mask respirator and goggles was the most feasible ensemble to control exposure to air pollutants in an anatomy laboratory.
American Journal of Industrial Medicine 04/2003; 43(3):326-31. · 1.63 Impact Factor
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Farhang Akbar-Khanzadeh
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ABSTRACT: In this study, the author examined (a) levels of airborne pollutants from environmental tobacco smoke in 8 restaurants, and (b) changes in urinary cotinine and nicotine levels among 97 nonsmoking subjects (i.e., 40 restaurant employees, 37 patrons, and 20 referents). Airborne pollutant levels were significantly lower in the control environments than in the nonsmoking dining rooms in which smoking was not permitted, and the levels were significantly lower in the dining rooms in which smoking was not permitted than in the dining rooms in which smoking was permitted. Levels of urinary cotinine and nicotine increased among subjects in the dining rooms in which smoking was permitted, and the increase was significantly greater in employees than patrons. There was a significant positive correlation between levels of urinary nicotine increase and the levels of airborne nicotine and solanesol. The results of this study support the restriction of smoking to designated areas that have separate ventilation systems, or the prohibition of smoking in restaurants.
Archives of Environmental Health An International Journal 03/2003; 58(2):97-103.
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ABSTRACT: Studies of the indoor air quality of restaurants have rarely focused on ventilation system performance in relation to air pollutants and climatic factors. This study was conducted in eight restaurants to examine this issue by determining the ventilation flow rates and the levels of carbon dioxide (CO2), ambient temperature, and relative humidity during at least one complete shift of serving a meal. The mean values of number of dining patrons, ventilation flow rates, and the levels of CO2, ambient temperature, and relative humidity were not significantly different in the nonsmoking dining rooms and the smoking dining rooms. The mean ventilation flow rates in individual restaurants ranged from 42-113 cubic feet per minute per person (cfm/person), overall exceeding the recommended lower limit of 30 cfm/person. The mean levels of CO2 in two restaurants (646 and 819 ppm) were below, and in the other six restaurants (ranging 1,012-1,820 ppm) were above the recommended upper limit of 1000 ppm. The levels of CO2 in each restaurant significantly correlated with the number of dining patrons and in four restaurants accumulated gradually over time. In the nonsmoking dining rooms, the levels of CO2 increased significantly as the ventilation How rates decreased. The mean ambient temperature in restaurants (ranging from 22 degrees C - 24 degrees C) were within the recommended range of 20 degrees C - 26 degrees C. The mean relative humidity in six restaurants (ranging from 46%-59%) were within the recommended upper limit of 60 percent, and in two restaurants (62% and 71%) were slightly higher than this recommended limit. It was concluded that although the mean ventilation flow rates in all restaurants exceeded the recommended value, the design of the ventilation system or the distribution of air flow rate in some sections of restaurants were not appropriate to keep the levels of CO2 and relative humidity at some measurement locations below the recommended limits.
Applied Occupational and Enviromental Hygiene 10/2002; 17(9):640-7.
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ABSTRACT: Studies reporting the findings of exposure to crystalline silica dust during concrete finishing in construction settings are scarce due to the dynamic nature of the activity and the existence of many confounding factors. This study was initiated to explore the issue. A total of 49 personal respirable dust samples were collected during concrete finishing while workers used hand-held grinders. Only 15 (31%) of the grinders were equipped with local exhaust ventilation (LEV) systems. The confounding factors (e.g. wind velocity, wind direction, relative humidity and ambient temperature) were determined. To make the sampling task-specific, air sampling was activated only during actual grinding. Task-specific sampling times during each work shift ranged from 10 to 200 min. The concentration of total respirable particulate ranged from 0.34 to 81 mg/m3, with a mean +/- SD of 18.6 +/- 20.4 mg/m3, and the concentration of crystalline silica in the samples ranged from 0.02 to 7.1 mg/m3, with a mean +/- SD of 1.16 +/- 1.36 mg/m3. LEV on the grinders reduced the silica dust level significantly (P < 0.01) compared to grinders without LEV. Increased wind velocity also reduced the silica dust concentration significantly (P < 0.03). Working upwind reduced the exposure to silica dust compared to working downwind, but the difference was not statistically significant. The time-weighted average concentration of silica dust in 69% of the samples exceeded the current recommended threshold limit value of 0.05 mg/m3, indicating a strong need to devise methods for controlling workers' exposure to crystalline silica dust during concrete finishing activities.
Annals of Occupational Hygiene 04/2002; 46(3):341-6. · 1.95 Impact Factor
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ABSTRACT: The degree of comfort of personal protective equipment (PPE) was investigated in an automobile encapsulating plant. Up to 96.2% of employees used one or a combination of PPE. Only 8% of the workers felt their respirators were comfortable, 30% tolerated their respirators, and 62% rated them as uncomfortable. The percentage of employees who rated their PPE (other than a respirator) as comfortable ranged from 32 to 52%. For comfort factor, coveralls/aprons rated 52%, safety glasses 51%, rubber gloves 42%, and hearing protectors 36%. PPE was tolerable (just acceptable) for about 30% of the employees. To increase the effectiveness and safety of PPE, the human-factor aspects of PPE design should be emphasized more and quality improvement should cover the wearability of PPE.
Applied Ergonomics 07/1995; · 1.43 Impact Factor
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ABSTRACT: Formaldehyde exposure, acute pulmonary response, and exposure control options were evaluated in a group of 34 workers in a gross anatomy laboratory. Time-weighted average (TWA) exposure to formaldehyde ranged from 0.07–2.94 parts per million (ppm) during dissecting operations. More than 94% were exposed to formaldehyde in excess of the ceiling value of 0.3 ppm recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The eight-hour TWA exposure of 31.7% of the subjects exceeded the action level of 0.5 ppm set by the Occupational Safety and Health Administration (OSHA). Reported symptoms included irritation of eye (88%), nose (74%), throat (29%), and airways (21%). Forced vital capacity (FVC) and forced expiratory volume in 3 seconds (FEV3) decreased, and FEV1/FVC increased during the exposure. The changes of FEV3 were statistically different from those of the controls. The results strongly support the necessity for designing and testing special local exhaust-ventilated worktables with necessary flexibility for dissecting operations.
American Journal of Industrial Medicine 06/1994; 26(1):61 - 75. · 1.63 Impact Factor
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ABSTRACT: This study develops information about assess worker's (faculty, research, staff and graduate students) exposure to ultraviolet radiation emitted from a sample of UV-transilluminators at all three UVR regions as well as at the actinic hazard spectral range
