Personal exposure monitors

FIGURE 15.15 Geometric mean PM1(I concentrations outdoors, indoors, and by personal exposure monitors during the day and at night in Riverside, California, weighted to provide estimates of concentrations for household-days or person-days. The error bars are 90th percentile (data from Clayton et at., 1993). 

A second product, the Organic Vapor Monitor, was introduced to the market in January of 1978. An additional patent on personal exposure monitoring was issued in July of 1978. 

Of course, on considering personal exposure monitoring by any method, it is helpful to have a point or frame of reference. In this case, that point of reference is the established pump and tube method. It features a mechanical pump whose function is to draw a constant, measured flow of an air-vapor mixture through a tube, normally consisting of two sections, where the vapors are selectively adsorbed. 

Exposure studies can be carried out aiming to estimate exposure of one individual (personal exposure) or of a larger population group (population exposure), through direct or indirect methods. Direct methods are measurements made by personal portable exposure monitors. The personal exposure monitoring devices that people carry with them must be lightweight, silent, highly autonomous and... 

Personal exposure monitor A device worn on or near the contact bonndary that measures concentration (Zartarian et al., 1997). 

Other analyzers include gas chromatography, which is a sensitive, automated, and semi-continuous technique in which CO is separated from water, CO2, and hydrocarbons (other than methane) by a stripper column and CO is passed through a catalytic reduction tube where it is converted to methane. The converted CO is passed through a flame ionization detector its sensitivity range is 0.026 to 43.7 ppm (IPCS, 1999). Other methods such as small personal exposure monitors (PEMs) can measure CO concentrations on a continuous basis and store data on internal digital memories (Ott et ah, 1986). 

Ott, W.R., Rodes, C.E., Drago, R.J., Williams, C., Burmarm, F.J. (1986). Automated data-logging personal exposure monitors for carbon monoxide. J. Air Pollut. Control Assoc. 36 883-7. 

Lewtas J, Dobias L, Binkova B, et al. 1994. Exposure-dosimetry of PAH in humans using DNA adducts as the biomarker of dose and personal exposure monitors for PAH. Proc Am Assoc Cancer Res 35 95. 

Other studies of UK homes using the same sampling and analytical procedures as reported by Berry et al. (1996) are summarised in Table 1.5-6. In addition the technique has been used for personal exposure monitoring to examine the relationship between VOC concentrations determined by fixed-site samplers in different micro-environments and those attached to the clothing of people using those micro-environments (Mann et al.,... 

L.T. HaU, J. Van Emon, V. Lopez-AvUa, Development of Immnnochemical Personal Exposure Monitors for Pentachlorophenol , Environ. Process Monitoring Tech- o/., 1637,189-195 (1992). 

Although they have only been used in a limited number of cases, they have proved to give excellent results in special applications. For example, they are used in many plants and operations of the chemical industry for personal exposure monitoring of phosgene. Other examples include the determination of personal exposure doses of formaldehyde or ethylene oxide in clinical applications. 

ADVANCES IN EXPOSURE ASSESSMENT PERSONAL EXPOSURE MONITORING... 

Advances in personal monitoring for exposure assessment studies are currently dependent upon the development of reliable analytical techniques and instrumentation applicable to PEMs. Currently PEMs for carbon monoxide are the most highly developed and evaluated. Carbon monoxide is an emission product which can be directly related to lead emissions from automotive combustion. Personal exposure monitors for CO are being used in urban studies to obtain population exposure data on a real time basis. This information can be used in risk assessment. 

While personal exposure monitoring Is the most reliable approach for assessing the level of respiratory protection required, it may not always be necessary to take personal exposure measurements to determine whether (or what level of) respiratory protection is needed. Appropriate safety factors should be used when using estimates of employee exposures. 

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