A rationale for sampling deposited submicrometer beryllium particulate matter.
The established particle size-selective criteria are based on the probability of an aerosol penetrating into the lung rather than depositing. For submicrometer particulate matter, penetration is a constant 100%, while deposition fluctuates. The deposited submicrometer particulate criterion has been suggested as a more appropriate measure of exposure for particles less than 1 mu m in size. There is some preliminary evidence that these smaller particles may be of significance for chronic beryllium disease. It has also been suggested that particle number might provide a better surrogate of exposure than total mass for beryllium sampling. There are two basic approaches that can be used for sampling for a deposition based criterion. The first is to determine the overall size distribution and apply a deposition factor based on the geometric mean and geometric standard deviation to the total amount of material collected. The second approach is to have specifically designed equipment for the deposition criterion of interest. This second approach is more practical, and methods are available and are being developed to make it available to the hygienist. Although there are reasons to believe that submicrometer-deposited beryllium particles are associated with the risk of beryllium disease, these measures need to be made so that epidemiologists will have the data available to fully confirm their relevance. Where the data already exist, epidemiologists need to be aware that there is evidence supporting using it their analyses.
McCawley
M
M
Department of Community Medicine, School of Medicine, West Virginia University, Morgantown, West Virginia 26506, USA. mccawley.mike@comcast.net
D001608:Beryllium / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D016273:Occupational Exposure / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*
D052638:Particulate Matter; D001608:Beryllium