Measurements were made of the number concentrations of particles in exhaled breath under various conditions of exercise. A laser light scattering particle spectrometer was used to count particles exhaled by test subjects wearing respirators in a challenge environment of clean, dry air. Precautions were taken to ensure that particles were not generated by the the respirators and that no extraneous water or other particles were produced in the humid exhaled air. The number of particles detected in exhaled air varied over a range from less than 0.1 to about 4 particles per cm3 depending upon the test subject and his activity. Subjects at rest exhaled the lowest concentration of particles, whereas exercises producing a faster respiration rate caused increased exhalation of particles. Exhaled particle concentrations can limit the usefulness of nondiscriminating, ambient challenge aerosols for the fit testing of highly protective respirators.

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The literature on the popular music museum has primarily focused on the study of heritage and cultural memory with a secondary focus on tourism. Given the unprecedented expansion of the museum sector worldwide in recent decades, which has produced an increasing number of major museums dedicated to popular music, it is an opportune time to expand this range of analytical concerns. Specifically, the development of popular music museums has not yet been closely examined within the broader historical trajectory of the so-called ‘new museum.’ This article seeks to outline the range of exhibitionary types commonly used in a range of high-profile popular music museums in pursuit of this line of inquiry. The goal is not simply to produce a generic survey or typology of displays, but to place the use of different forms of museum display within the specific historical trajectory that has produced steadily larger numbers of these kinds of museums in recent years. I organize these exhibitionary types into two broad streams of museum exhibition practice implied in the historical survey presented here: a populist-vernacular stream of museum display and an institutional-educational one. I seek to place the exhibitionary practices of contemporary popular music museums in a broader and longer trajectory of similar practices in order to get a more grounded sense of the more important characteristics of these kinds of museums.