Farhang Akbar-Khanzadeh

Comfort of personal protective equipment

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.

Characterizing Formaldehyde Emission Rates in a Gross Anatomy Laboratory

The evaporation of formaldehyde from cadavers in gross anatomy laboratories can produce high exposures among students and instructors. To understand the system that produces exposures and to plan for implementing control options, the generation of formaldehyde vapors must be characterized. A gross anatomy laboratory with 47 dissecting tables was studied during 15 lab sessions over a period of 16 weeks. Area concentrations were measured using National Institute of Occupational Safety and Health (NIOSH) method 3500. Average daily area concentrations in the laboratory ranged from 0.635 to 1.82 mg/m3. The ventilation was characterized on three separate days. The laboratory had a general ventilation rate of 9.8 air changes per hour. There was no local exhaust ventilation. The concentration measurements were used in a mass balance model along with ventilation rates to determine formaldehyde emission rates. The daily average formaldehyde emission rate from all sources in the laboratory ranged from 95.2-274 mg/min, with an average of 148 mg/min over the course of the study. This total emission rate was used along with the number of dissecting tables to develop an emission factor of 3.15 mg/min per table. The emission factor is a generalizable tool that can be used in laboratories of various sizes to predict emission rates and develop control strategies. This emission factor is applicable where the cadavers are prepared with similar embalming fluid consisting of approximately 10 percent formaldehyde.

Crystalline Silica Dust and Respirable Particulate Matter During Indoor Concrete Grinding—Wet Grinding and Ventilated Grinding Compared with Uncontrolled Conventional Grinding

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 operators 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/m3 and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m3. 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/m3 (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.

Exposure to Environmental Tobacco Smoke in Restaurants without Separate Ventilation Systems for Smoking and Nonsmoking Dining Areas

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.

Effectiveness of Dust Control Methods for Crystalline Silica and Respirable Suspended Particulate Matter Exposure During Manual Concrete Surface Grinding

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/m 3 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/m 3 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/m 3 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/m 3 for crystalline silica, requiring further refinement in engineering controls, administrative controls, or the use of respirators.

Field Precision of Formaldehyde Sampling and Analysis Using NIOSH Method 3500

This study examined the field precision of National Institute for Occupational Safety and Health (NIOSH) Method 3500, also known as chromotropic acid method, in the range of exposure limit covers the Occupational Safety and Health Administration (OSHA) permissible exposure limit of 0.75 ppm and the OSHA action level of 0.5 ppm airborne formaldehyde. Using this method, 78 area samples (25 sets of replicate samples) were collected in a workplace and analyzed. The concentrations of formaldehyde ranged from 0.05 to 1.72 ppm with a mean +/- standard deviation of 0.95 +/- 0.31 ppm. The precision (coefficient of variation, CV) of 25 sets of replicated samples ranged from 0.03 to 0.24 with an overall (pooled) precision of 0.09, which is in agreement with that stated in NIOSH Method 3500. In 68% of replicate samples the precision was equal to or less than 0.09. The relative accuracy of the sampling and analytical procedure used in this study was evaluated by collecting 12 sets of side-by-side replicate samples using both NIOSH Method 3500 and OSHA Method 5.2 Method 53 was used to determine whether the concentrations of formaldehyde were within the desired range. The overall mean concentrations were 0.98 +/- 0.42 for Method 3500 and 0.78 +/- 0.28 ppm for Method 5.2. These were no statistically different. The pooled CVs were 0.114 and 0.076 for Method 3500 and Method 52, respectively.

Indoor air quality in restaurants with and without designated smoking rooms.

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.

Safety and Health Program Assessment in Relation to the Number and Type of Safety and Health Violations

The Ohio Bureau of Employment Services (OBES), through the Occupational Safety and Health Administration On-Site Consultation Program, provides safety and health (S&H) consultation services to small high-hazard companies. During a full-service consultation, the S&H Program Assessment Worksheet (Form 33) is completed and the S&H violations are determined. Form 33 consists of 25 indicators, each with a score of 0 (lowest) to 4 (highest) to evaluate a portion of the S&H program. To examine the hypothesis that employers with a higher score on their S&H program would have fewer S&H violations, a study collected and analyzed data from records maintained in the archives of OBES. Of 534 full-service site visits performed between June 1995 and December 1996, 107 case files were complete and appropriate for this study. Data analysis revealed that the number of serious violations (SV) and the number of regulatory violations (RV) were significantly (p < 0.01) correlated to all 25 indicators on the S&H Program Assessment Worksheet, whereas the number of other-than-serious violations (OSV) were significantly (p < 0.05) correlated to only 15 indicators. The best predictors of the number of SV were the indicators of Timely Hazard Control and Emergency Planning and Preparation; best predictors of RV were the indicators of Timely Hazard Control and Accountability; and best predictors of OSV were the indicators of Hazard Identification (Self-Inspection) and Emergency Planning and Preparation (Equipment). Employers who scored higher on the indicators of the quality of their S&H programs had fewer S&H violations, and the indicators of Hazard Identification, Timely Hazard Control, and Emergency Planning and Preparation showed the highest influence in reducing violations.

Exposure to Particulates and Fluorides and Respiratory Health of Workers in an Aluminum Production Potroom with Limited Control Measures

Occupational exposure to air pollutants and health status of potroom workers of an aluminum reduction plant in a developing country were studied and compared with those in developed countries. In this plant, the pots were constructed and installed without recommended gas collecting hoods or segmented side doors, and the workers did not use any respiratory protection. These conditions, combined with manual material handling and poor housekeeping, gave rise to fugitive air pollution generation. All 213 male potroom workers and 148 male control subjects were studied using air sampling, urinary fluoride measurement, ventilatory function testing, and a questionnaire on respiratory symptoms. On average, breathing zone respirable and total particulates in the potroom were 0.98 and 1.82 mg/m3, respectively. Stationary air sampling showed 0.93 mg/m3 of total fluoride, 2.09 mg/m3 of respirable particulates, and 7.59mg/m3 of total particulates. During an 8-hr shift, the average increase of urinary fluoride in the po...

Particulate Matter (PM) Exposure Assessment—Horizontal and Vertical PM Profiles in Relation to Agricultural Activities and Environmental Factors in Farm Fields

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/m3) 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/m3) 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.