An inter-laboratory study to determine the effectiveness of procedures for discriminating amphibole asbestos fibers from amphibole cleavage fragments in fiber counting by phase-contrast microscopy.

The US Occupational Safety and Health Administration (OSHA) and Mine Safety and Health Administration do not regulate cleavage fragments of amphibole and serpentine minerals as asbestos, even when particles meet the dimensional criteria for counting under standard phase-contrast microscopy methods. The OSHA ID-160 method cautions that discriminatory counting is difficult and should not be attempted unless necessary and no procedure is provided for differentiation. A standard published by the American Society for Testing and Materials (ASTM International D7200-06) includes an attempt to codify a procedure but recognizes that the procedure should be validated in an inter-laboratory study.

Do we really need SEVEN new aerosol particle sampling conventions?

The rationale behind recently proposed aerosol particle sampling conventions is discussed. The conventions are tailored toward estimation of dose to specific areas of the human respiratory tract prior to possible dissolution or clearance. Allowance is made for inter- and intra-person variation.

Sampling conventions for estimating ultrafine and fine aerosol particle deposition in the human respiratory tract.

Objectives: To provide targets for personal samplers designed for estimating particle deposition at distinct locations in the body, accounting if necessary for inter- and intra-person variation.

Proposal: Ultrafine and fine aerosol sampling conventions are proposed for approximating the deposition efficiency for five distinct loci of the respiratory tract. The 2 × 5 = 10 conventions represent averages over variation in physical activity level, posture, sex, and breathing mode.

Interlaboratory evaluation of a standardized inductively coupled plasma mass spectrometry method for the determination of trace beryllium in air filter samples.

A collaborative interlaboratory evaluation of a newly standardized inductively coupled plasma mass spectrometry (ICP-MS) method for determining trace beryllium in workplace air samples was carried out toward fulfillment of method validation requirements for ASTM International voluntary consensus standard test methods. The interlaboratory study (ILS) was performed in accordance with an applicable ASTM International standard practice, ASTM E691, which describes statistical procedures for investigating interlaboratory precision. Uncertainty was also estimated in accordance with ASTM D7440, which applies the International Organization for Standardization Guide to the Expression of Uncertainty in Measurement to air quality measurements.

The meaning of the bias uncertainty measure.

Characterization of measurement uncertainty in terms of root sums of squares of both unknown systematic as well as random error components is given meaning in the sense of prediction intervals. Both types of errors are commonly encountered with industrial hygiene air monitoring of hazardous substances. Two extreme types of measurement methods are presented for illustrating how confidence levels may be ascribed to prediction intervals defined by such uncertainty values.

The ups and downs of journal impact factors.

The journal impact factor (JIF) for The Annals of Occupational Hygiene rose 68% between 2005 and 2006. JIFs are widely publicized and may influence subscriptions and where authors submit papers, so they are much discussed in the publishing world. But although they tell us something about a journal's citation performance, their shortcomings mean that they are poor general indicators of journal quality, and worse guides to the quality of authors and their institutions.

Portable XRF analysis of occupational air filter samples from different workplaces using different samplers: final results, summary and conclusions.

This paper concludes a five-year program on research into the use of a portable X-ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here.

Uncertainty determination for nondestructive chemical analytical methods using field data and application to XRF analysis for lead.

Air sampling and analytical methods are developed to provide a basis for decision making. They are evaluated in the laboratory against prescribed fitness-for-use criteria even though laboratory validation does not take into account all possible sources of uncertainty in field application. Field evaluation would be preferable but is complicated by the lack of controlled conditions, which limits the ability to compare analytical methods and to recognize outliers and assess variance homogeneity across the range of interest.

Frequency distributions from birth, death, and creation processes.

The time-dependent frequency distribution of groups of individuals versus group size was investigated within a continuum approximation, assuming a simplified individual growth, death and creation model. The analogy of the system to a physical fluid exhibiting both convection and diffusion was exploited in obtaining various solutions to the distribution equation. A general solution was approximated through the application of a Green's function.