TRANSURANIC AND TRACER SIMULANT RESUSPENSION 271 



lO^r 



Fig. 23 Airborne particle volume 

 distributions at Hanford. 



1 10 10^ 



PARTICLE DIAMETER (D), /im 



1973a). The range obtained with the optical particle counter is shown as a crosshatched 

 area. The cowl-impactor data have an upper limit, increasing with wind speed and 

 decreasing height (the April 1972 data), and a lower limit for other test periods, indicated 

 by the lines described by 3.46 D°' ' and 1 160 D" ^ ■''^, where D is the particle diameter. 

 The upper, or maximum, limits of the curves for any particle diameter were integrated as 

 a function of particle diameter to determine maximum airborne mass loadings. The lower 

 limits were also integrated as a function of particle diameter. These integrations predicted 

 the solids mass loading per unit volume of air (shown in Table 10) as a function of four 

 different particle diameter ranges: 0.16 to 1, 1 to 10, 10 to 100. and 100 to 230 (jtm. 



Particles less than 10 /im in diameter are frequently considered respirable (i.e.. small 

 enougli to be inhaled into the lungs), even though 3.5 nm appears to be more exact. In 

 the following discussion, particles with diameters less than 10 /jm are considered 

 respirable and those larger dian lOjum are nonrespirable. 



