The Pollen Concentration of the Atmosphere

Abstract

Methods of computing the number of pollen granules per unit volume of air are reviewed. Much of the published data concerning quantitative atmospheric pollen pollution are incorrect since these data were obtained through employment of factors which are incorrect. Cocke has recently pointed out that Scheppegrell in devising these widely used factors made the error of using the diam. instead of the radius in making application of Stokes'' Law; but Cocke, in correcting these factors, also made certain errors of calculation. The application of Stokes'' Law in this connection may be improper since it presumes the density of pollen to be unity, whereas little is known concerning pollen densities. Until more is learned concerning the density of the various pollens it is preferable to express atmospheric pollen conc. on a unit area basis of exposed slides.