Performance capability of respirators has traditionally been evaluated by testing components of the respirator (e.g., filter efficiency), facepiece fit, total inward leakage, or some other measure of performance evaluated under laboratory conditions. In recent years, increased emphasis has been placed on development of test methods suitable for evaluating respirator performance in the workplace. The goal of such testing is to evaluate the level of protection provided by respirators in the work environment. The AIHA Respiratory Protection Committee believes that workplace testing of respirators has the potential to be an excellent tool for increasing knowledge about the effectiveness of respiratory protection. However, a number of technical issues remain to be addressed before optimal test protocols and data analysis methods can be defined. The progress made to date in workplace testing will be reviewed, and broader discussion about key elements that must be considered when developing guidelines for testing respirators in the workplace will be initiated.

Respiratory protection is used as a method of protecting individuals from inhaling harmful airborne contaminants and in some cases to supply them with breathable air in oxygen-deficient environments. This article focuses on the use and types of personal respiratory protection (respirators) worn by individuals at workplaces where airborne hazardous contaminants may exist. Respirators are increasingly also being used in nonindustrial settings such as health care facilities, as concerns regarding infectious epidemics and terrorist threats grow. Pulmonologists and other clinicians should understand fundamental issues regarding respiratory protection against airborne contaminants and the use of respirators.

In late 2001, some U.S. Postal Service workers and a few members of Congress were exposed to anthrax spores. This led to an increased effort to develop employable methods to protect workers from exposure to anthrax. Some investigations focused on selection and use of respirators to protect workers against airborne anthrax. The present study evaluated the potential for several types of half-mask respirators to release deposited particles. Four brands of the most commonly used filtering facepiece respirators (hereafter termed masks) were loaded with 0.59-μm, 1.0-μm, and 1.9-μm polystyrene latex (PSL) microspheres (nominally 0.6, 1.0, and 2.0 μm) and then dropped onto a rigid surface. The load conditions were 10, 20, or 40 million particles, and drop heights were 0.15, 0.76, and 1.37 m. For the average conditions of 0.76 m, 1.15 μm size and 22 million particles loaded, the average particle release was 0.604 particles per 10,000 (95% CI: .552, .662) particles loaded for all of the filtering facepieces tested. The averaging of conditions is a useful tool to provide generalized information and is also useful when making risk estimates. For most filtering facepiece respirators, particle release tended to increase with drop height and particle size, and there appeared to be a slight inverse relationship with particle load. Two brands of reusable elastomeric half-mask respirators with P100 high-efficiency particulate air (HEPA) filter cartridges were also evaluated. Results of these tests were inconclusive. Part II in this issue addresses the release of particles when simulating removal of a filtering facepiece from a wearer's head.

This study evaluated the potential for disposable filtering facepiece respirators (hereafter termed masks) contaminated with 1-μ m particles to release particles as a result of lateral tension applied to the mask. The lateral tension was designed to simulate the removal of a contaminated mask from a user's head. Four brands of filtering facepieces were loaded with approximately 20 million 1.0-μ m polystyrene latex (PSL) microspheres. The respirators were then placed in a test chamber and subjected to lateral tension between 17.8-26.7 N (4-6 lbs) for 1 to 2 sec. The findings suggest that neither mask type nor loading condition affects particle release. This supports our hypothesis that when filtering facepiece respirators are properly removed from the head they will not release a significant number of particles.

The respirators have been used for almost 2000 years and the genesis of their technical development is actually the mid‐19th century. The Bureau of Mines in 1919 initiated the first respirator certification program in the United States and certified their first respirator. In 1995, NIOSH proclaimed new certification regulations. The study finds that the respiratory protective equipment (RPE) should be used only when all higher priority control steps are not technically or financially feasible. Thus, RPE continues to be an important component in many respiratory exposure control plans. The present study also addresses the performance of RPE and its evaluation in the laboratory and in the workplace. The respirator program ensures that the RPE selected is able to provide adequate protection under the conditions of intended use.