An inhalable-dust sampler, for measuring the hazard fron total airborne particulate

Present standards and measurement methods for total airborne particulate are very inexact because they usually ignore the sampler entry effects important for large particles. A logical solution would be to try to measure the same concentration as enters the nose or mouth. Calm-air results for this human entry efficiency are presented, completing measurement of this in winds between 0 and 2.75 m/s. A 47 mm filter holder is described, which is shaped so that over this range of windspeeds it has approximately the same entry efficiency, up to at least 25 μm aerodynamic diameter, as a human head equally exposed to all wind directions. Measurements of ‘total’ airborne particulate with this sampler should be much more consistent and relevant than with the usual methods. The influence of turbulence on such measurements is discussed briefly.