A significant portion of the work of developing and validating methods for volatile organic compound (VOC) sampling in workplace atmospheres involves the use of laboratory-generated atmospheres. The sample variability was evaluated from the dynamic atmosphere generation system used for VOC atmosphere generation and sampling. Characterization of the bias and variability of samples was done for a variety of atmospheres containing neat n-heptane and mixtures of VOCs sampled on activated coconut shell charcoal. Estimates of sampling variability ranged from 2% for neat n-heptane to 12% for a component in the 10 VOC mix. Sample variability increased for lower concentration samples and for mixtures of VOCs compared to single component atmospheres. This study can serve as a baseline for future atmosphere sampling experiments evaluating performance at lower concentrations and mixed VOC environments.

An evaluation was carried out to investigate the suitability of polyvinyl chloride (PVC) internal capsules, housed within air sampling devices, for gravimetric analysis of airborne particles collected in workplaces. Experiments were carried out using blank PVC capsules and PVC capsules spiked with 0,1 - 4 mg of National Institute of Standards and Technology Standard Reference Material(®) (NIST SRM) 1648 (Urban Particulate Matter) and Arizona Road Dust (Air Cleaner Test Dust). The capsules were housed within plastic closed-face cassette samplers (CFCs). A method detection limit (MDL) of 0,075 mg per sample was estimated. Precision S(r) at 0,5 - 4 mg per sample was 0,031 and the estimated bias was 0,058. Weight stability over 28 days was verified for both blanks and spiked capsules. Independent laboratory testing on blanks and field samples verified long-term weight stability as well as sampling and analysis precision and bias estimates. An overall precision estimate Ŝ(rt) of 0,059 was obtained. An accuracy measure of ±15,5% was found for the gravimetric method using PVC internal capsules.

In 1973, the National Institute for Occupational Safety and Health (NIOSH) published the first edition of the NIOSH Manual of Analytical Methods (NMAM®). It contained 38 procedures developed by chemists at NIOSH. Today, the NMAM is accessible on the Internet at http://www.cdc.gov/niosh/docs/2003-154/ and contains more than 300 methods. | The NMAM, a compendium of validated methods for measuring occupational exposures to hazardous substances, is one of the most successful products in NIOSH history. The current fourth edition( Citation1 ) is the second most visited and downloaded document on the NIOSH website (receiving an average 30,000 visits per month, 60% of these international; Figure 1 shows the distribution by region.) The methods most often downloaded are shown in Figure 2, with metals, hydrocarbons, and particulates comprising the top three.