Applied occupational and environmental hygiene最新文献

Exposure to hazardous impulse noise is common during the firing of weapons at indoor firing ranges. The aims of this study were to characterize the impulse noise environment at a law enforcement firing range; document the insufficiencies found at the range from a health and safety standpoint; and provide noise abatement recommendations to reduce the overall health hazard to the auditory system. Ten shooters conducted a typical live-fire exercise using three different weapons--the Beretta.40 caliber pistol, the Remington.308 caliber shotgun, and the M4.223 caliber assault rifle. Measurements were obtained at 12 different positions throughout the firing range and adjacent areas using dosimeters and sound level meters. Personal and area measurements were recorded to a digital audio tape (DAT) recorder for further spectral analysis. Peak pressure levels inside the firing range reached 163 decibels (dB) in peak pressure. Equivalent sound levels (Leq) ranged from 78 decibels, A-weighted (dBA), in office area adjacent to the range to 122 dBA inside the range. Noise reductions from wall structures ranged from 29-44 dB. Noise abatement strategies ranged from simple noise control measures (such as sealing construction joints and leaks) to elaborate design modifications to eliminate structural-borne sounds using acoustical treatments. Further studies are needed to better characterize the effects of firing weapons in enclosed spaces on hearing and health in general.

A dynamic aerosol mass concentration measurement device has been developed for personal sampling. Its principle consists in sampling the aerosol on a filter and monitoring the change of pressure drop over time (Delta P). Ensuring that the linearity of the Delta P = f(mass of particles per unit area of filter) relationship has been well established, the change of concentration can be deduced. The response of the system was validated in the laboratory with a 3.5 microm alumina aerosol (mass median diameter) generated inside a 1-m(3) ventilated enclosure. As the theory predicted that the mass sensitivity of the system would vary inversely with the square of the particle diameter, only sufficiently fine aerosols were able to be measured. The system was tested in the field in a mechanical workshop in the vicinity of an arc-welding station. The aerosol produced by welding is indeed particularly well-adapted due to the sub-micronic size of the particles. The device developed, despite this limitation, has numerous advantages over other techniques: robustness, compactness, reliability of calibration, and ease of use.

Occupational and environmental health professionals are confronted with issues concerning the health effects of indoor fungal bioaerosol exposure. This article reviews current data on the health effects of indoor mold exposure and provides practical suggestions for occupational and environmental health practitioners regarding how best to manage these exposures based on published human studies. We conducted MEDLINE searches and reviewed all English language studies on indoor mold exposure (visible survey or objective sampling) and human health effects published from 1966 to November 2002. The main findings of the studies are analyzed in conjunction with plausible association of health effects and fungal exposure. Five case control studies, 17 cross-sectional surveys, and 7 case reports met the selection criteria. Current evidence suggests that excessive moisture promotes mold growth and is associated with an increased prevalence of symptoms due to irritation, allergy, and infection. However, specific human toxicity due to inhaled fungal toxins has not been scientifically established. Methods for measuring indoor bioaerosol exposure and health assessment are not well standardized, making interpretation of existing data difficult. Additional studies are needed to document human exposure-disease and dose-response relationships.

This case study describes occupational exposures to coal tar pitch volatiles (CTPV) as benzene soluble fraction (BSF), polycyclic aromatic hydrocarbons (PAHs) and total particulates at a unique operation involving the use of coal tar in the making of expansion joints in construction of a multi-level airport parking garage. A task-based exposure assessment approach was used. A set of 32 samples was collected and analyzed for total particulate and CTPV-BSF. Twenty samples of this set were analyzed for PAHs. Current American Conference of Governmental Industrial Hygienists (ACGIH(R)) respective threshold limit value-time weighted average (TLV-TWA) for insoluble particulates not otherwise specified (PNOS) is 10 mg/m(3) as inhalable dust, which roughly corresponds to 4 mg/m(3) total particulate; for CTPV as BSF the TLV is 0.2 mg/m(3), and for specific PAHs such as benzo(a)-pyrene (B[a]P), ACGIH suggests keeping exposure as low as practicable. The recommended Swedish exposure limit for B(a)P is 2 microg/m(3). The highest exposure levels measured were 12.8 mg/m(3) for total particulate, 1.9 mg/m(3) for coal tar pitch volatiles as BSF, and 12.8 microg/m(3) for B(a)P. Several of the CTPV-BSF results were over the TLV of 0.2 mg/m(3). The data set is limited; therefore, caution should be used in its interpretation.

There have been historic concerns that lead has existed as a plasticizer in telephone lines, causing health hazards, especially for children, who frequently mouth, chew, and swallow non-food items. The acid environment of the mouth may leach lead from the surface into the saliva under non-destructive conditions. Thus, distinguishing the amount of lead in the surface versus the inside of the polyvinyl chloride (PVC) material covering the phone cord line is very important in assessing health hazards. Using X-ray Photoelectron Spectroscopy (XPS), we measured lead in the PVC covers of telephone cords that connect the handheld part of the phone to the base. Lead was detected in both the inner and outer surface of an older (approximately 12 years) cord (1.3 atomic percent in inner surface; 0.4 atomic percent in the outer surface). However, when we tested four popular brands of newer cords (currently available in the market), there was no detectable lead. This study demonstrates that XPS is a useful technique that can distinguish lead contents between surface versus inner core of plasticized telephone cords. Telephone cords and other plasticized materials that may leach lead should be screened to establish safety.

This article presents an assessment of indoor air quality at a bus terminal. For this purpose, field surveys were conducted, and air samples were collected and analyzed for the presence of selected indoor air quality indicators. Mathematical modeling was performed to simulate bus emission rates, occupational exposure, and ventilation requirements to maintain acceptable indoor air quality. A sensitivity analysis based on literature-derived emission rates estimates was conducted to evaluate the effect of seasonal temperature changes within the terminal. Control measures to improve indoor air quality at the terminal are also outlined. While carbon monoxide concentrations were below the corresponding American Conference of Governmental Industrial Hygienists' (ACGIH) standards under normal operating conditions, they exceeded the 8-hr recommended average standard at peak hours and the World Health Organization (WHO) standard at all times. Total suspended particulates levels, on the other hand, were above the 24-hr American Society of Heating, Refrigerating and Air Conditioning Engineers' (ASHRAE) standard. Carbon monoxide emission rates that were estimated using the transient mass balance model correlated relatively well with those reported in the literature. Modeling results showed that the natural ventilation rate should be at least doubled for acceptable indoor air quality. While pollutant exposure levels depended on the individual activity patterns and the pollutant concentration, pollutant emissions rates within the terminal were affected mostly by the temperature with a 20-25 percent variation in carbon monoxide levels due to changes in seasonal temperatures.