American Industrial Hygiene Association journal最新文献

This study investigated whether there is a relationship between high physical work load and adverse psychosocial work factors, and whether this relationship is different for women and men. Separate analyses for female registered nurses and assistant nurses were made because these are common occupations involving high physical and psychological demands. This study was part of the MUSIC-Norrtälje study, a population study with the overall aim of identifying risk factors for musculoskeletal disorders. The respondents, 1423 gainfully employed men and women, were randomly selected from the study population. The exposure assessments referred to a typical workday during the previous 12 months. Physical exposure was investigated by interview, psychosocial work factors by interview and questionnaire. For the women, but not the men, mainly routine work and a job strain situation, according to the model of Karasek and Theorell, increased the probability of having a high physical work load, assessed as a time-weighted average of energy expenditure in multiples of the resting metabolic rate. Results indicated that in female-dominated occupations, high physical work load might also imply adverse psychosocial conditions. A higher frequency of high physical work load and job strain was observed among assistant nurses compared with registered nurses. Covariance between physical and psychosocial demands makes it difficult to determine the relative influence of each in health problems. Results of the present study imply that this is a larger problem in studies of women than men.

Performance of filters for the removal of ozone at ambient concentration is characterized. The removal efficiency and pressure drop of 10 commercial filters--including 8 made of granule or powdered activated carbon, 1 activated carbon fiber filter, and 1 packed bed made of an ozone catalyst--were measured for an influent ozone concentration of 120 ppb at 50% relative humidity and 2.54 m/sec face velocity. Activated carbon filters can be very effective at ozone removal, although not indefinitely because chemical reactions of ozone and carbon change the carbon. Initial efficiencies of the 1.27-cm thick flat samples varied from 4.6 to 98.3%. Analysis of the structure and composition of the filters with scanning electron microscopy and X-ray photoemission spectrometry showed chemical reactions permanently changed the composition of the carbon and decreased the surface area. Consequently, removal efficiency decreased with use. Moreover, it was not feasible to regenerate the filters by simply removing them from ozone-laden air. Changes in relative humidity, from 20 to 80%, had no measurable effect on the performance of a granule activated carbon filter. However, because the rate of adsorption of water is faster and the pores are smaller in activated carbon fiber, efficiency of the fiber filter decreased when relative humidity was raised from 20 to 50%. A quality factor, equal to the ratio of a threshold breakthrough time and pressure drop, is used to compare filters. In general, those with higher carbon surface area per unit volume had higher efficiencies and greater pressure drops. Future work should address the removal of ozone in the presence of other gases.

Exposures of refuse-derived fuel (RDF) production workers to total particulates, endotoxin, and total (viable plus nonviable) bioaerosols were characterized at two RDF production plants. Full-shift personal air monitoring for 35 workers was conducted for total particulates, analyzed by gravimetric analysis; endotoxin, analyzed by chromogenic endpoint assay; and total bioaerosols, analyzed by fluorescent microscopy (FM). Geometric mean values of personal air samples were 0.50 mg/m3 for total dust, 29.0 EU/m3 (2.9 ng/m3) for endotoxin, and 6.8 x 10(5) organisms/m3 for bioaerosols. Significant differences were observed between the two plants only for total endotoxin exposures. The mean concentrations for total particulates, total FM bioaerosols, and endotoxins did not differ among the day, evening, or night shifts. Interjob differences were found for exposures to total dust, total endotoxin, and FM bioaerosols. Individual comparisons for total particulates and endotoxin exposures were significant for comparisons between job categories as a result of the greater exposures for personnel cleaning the plants. Significant correlations were detected between total particulates and total endotoxin measurements and between inhalable and total particulates.

The purpose of this study was to assess diesel exhaust exposures in the electric utility industry and to compare these findings with worker exposures reported in other industries and to proposed and established occupational exposure limits. Two sampling approaches were used: particulates were analyzed for elemental (EC) and organic (OC) carbon via the thermal-optical method; and gaseous components (NO2, SO2, NO, and CO) were determined using a direct reading instrument, the Metrosonics pm-7400. Concentrations of the gases were all well within established occupational exposure levels. The EC percentage of the total carbon was generally lower than results reported from other studies resulting in OC levels representing a higher percentage of the total carbon concentrations. Smokers had higher average OC exposure (79 micrograms/m3) than nonsmokers (57 micrograms/m3), but cigarette smoke did not contribute to EC levels in this study (smokers and nonsmokers = 3 micrograms/m3). Two of 120 individual personal exposure levels were found to exceed the proposed threshold limit value of 150 micrograms/m3 for total particulate, but geometric mean levels were found to be significantly less than the proposed value. Questions are raised concerning the use of EC as the sole surrogate for estimating diesel content for comparison with an exposure standard.

This article presents a protocol system, comprised of a review process and a series of checklists, that was developed for testing cadaveric tissue in an impact biomechanics research facility. The use of cadaveric tissue may expose personnel to bloodborne pathogens including HIV and hepatitis B, which have been shown to remain virulent in a cadaver for several weeks after death. To minimize exposure risks, the protocol system presented emphasizes initial blood screening to keep infectious tissue from entering the laboratory, and adopts universal precautions to prevent exposure by treating all tissue as though it were infected. All lab employees must read, sign, and demonstrate proficiency in the protocol. Well-developed test procedures for the handling of biohazardous materials along with an annual individual protocol review have proven effective for the past 6 years in minimizing exposure risks.

Borates are susceptible to weight change due to uptake or loss of water and this hydration instability can lead to gravimetric and interpretation errors in occupational hygiene field sampling of dust. The hydration stability for inhalable borate dust particles (mean diameter 7-22 microns) was characterized over a range of ambient temperature and relative humidity conditions simulating field sampling. Borax 10 mol (Na2O.2B2O3.10H2O), a fully hydrated borate, has a relatively high vapor pressure to water that led to rapid dehydration with significant weight change. Low hydrate borates, Neobor borax 5 mol (Na2O.2B2O3.5H2O), anhydrous boric acid (B2O3), and anhydrous borax (Na2O.2B2O3) were found to hydrate rapidly with an increase in weight. In contrast, boric acid (B[OH]3) and borax 5 mol were found to be stable to dehydration under all conditions. Boron can be measured with high analytical accuracy, but because the specific borate species or borate compounds collected in a 37-mm dust sampler cannot be accurately identified, it is argued that occupational exposure values should be revised to reflect exposure to boron and exposure values for these borates should be the same based on equivalent boron content.

A new technique has been developed for determining the time-weighted average personal exposure to nitrous oxide gas. Nitrous oxide gas is passively collected on a molecular sieve contained in a glass tube and partially desorbed in a vial until solid-gas equilibrium at 100 degrees C. Next, nitrous oxide concentration in the head space air in the vial is measured with a gas chromatograph equipped with an electron capture detector. This study shows that nitrous oxide concentration in the head space is proportional to both the nitrous oxide concentration in the test atmosphere and the sampling time up to 1600 ppm/hr. The coefficient of variance is less than 10%. The performance of the sampler is not affected by water vapor or carbon dioxide in the atmosphere nor by air currents. The sampler can be stored for 2 weeks at either 4 or 25 degrees C. Because the passive sampler is small and light, it can be used to determine exposure to nitrous oxide during surgical operations.

Glycol-based fluids are used in the production of theatrical smokes in theaters, concerts, and other stage productions. The fluids are heated and dispersed in aerosol form to create the effect of a smoke, mist, or fog. There have been reports of adverse health effects such as respiratory irritation, chest tightness, shortness of breath, asthma, and skin rashes. Previous attempts to collect and quantify the aerosolized glycols used in fogging agents have been plagued by inconsistent results, both in the efficiency of collection and in the chromatographic analysis of the glycol components. The development of improved sampling and analytical methodology for aerosolized glycols was required to assess workplace exposures more effectively. An Occupational Safety and Health Administration versatile sampler tube was selected for the collection of ethylene glycol, propylene glycol, 1,3-butylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol aerosols. Analytical methodology for the separation, identification, and quantitation of the six glycols using gas chromatography/flame ionization detection is described. Limits of detection of the glycol analytes ranged from 7 to 16 micrograms/sample. Desorption efficiencies for all glycol compounds were determined over the range of study and averaged greater than 90%. Storage stability results were acceptable after 28 days for all analytes except ethylene glycol, which was stable at ambient temperature for 14 days. Based on the results of this study, the new glycol method was published in the NIOSH Manual of Analytical Methods.

Exposures to 1,1,2-trichloro-1,2,2-trifluoroethane or fluorocarbon (FC) 113 were evaluated in a horizontal laminar airflow (HLAF) clean room and a vertical laminar airflow (VLAF) clean room. A full period consecutive samples measurement strategy was employed. Data were used to calculate 8-hour time-weighted averages (8-TWA) for major work groups and to characterize exposures associated with specific cleaning tasks. The MIRAN 1B infrared analyzer was used to estimate peak concentrations. In the HLAF clean room, 8-TWAs ranged from 193 to 439 ppm; in the VLAF clean room, 8-TWAs ranged from 110 to 935 ppm. These levels were below the current Occupational Safety and Health Administration permissible exposure limit and the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit for FC 113 of 1000 ppm. Short-term sample concentrations ranged from 104 ppm (inspection) to 1080 ppm (assembly) in the HLAF clean room and 51 ppm (packaging)-3380 ppm (flushing) in the VLAF clean room. In the VLAF clean room, several short-term concentrations measured during the flushing task--1421 ppm and 2522 ppm--were above the NIOSH short-term exposure limit (STEL) of 1250 ppm. These data suggest the possibility that the STEL may be exceeded for tasks involving direct work with liquid FC 113. Peak exposure levels may be reduced by modification of worker position in the HLAF clean room and by use of open wire tables in the VLAF clean room.