Transport of particles to surfaces

Stable (206Pb, 207Pb, 208Pb) and radioactive (210Pb) lead isotopes in 1year of growth of Sphagnum moss from four ombrotrophic bogs in southern Germany: Geochemical significance and environmental implications

“…Retention of particles by mosses was found to exceed that by lichens by 2-3 times, probably due to a combination of more efficient retention by the moss, greater plant density, and higher leaf surface area (Taylor and Witherspoon, 1972). Using particles ranging in size from 0.08 to 30 lm and labelled with 131 I, Clough (1973) showed that deposition velocity (radioactivity in plant per unit area/radioactivity in air per unit volume) of particles to surfaces (such as filter paper) were at a minimum for particles on the order of 0.5 lm, with velocities increasing both with increasing and decreasing size from this point.…”

“…The microtopography of the leaf surface, wetness (Clough, 1973), stickiness, hairiness, and electric charge on the leaf surface are all important factors, as are the size, density, and shape of the aerosols, chemical composition and water solubility, and electric charge (Lindberg and Harriss, 1981;Hosker and Lindberg, 1982). Some plant leaves have the ability to cleanse themselves of atmospheric particulates, a process called "the lotus effect" (Barthlott and Neinhuis, 1997).…”

Measurements of dust deposition velocity in a wind-tunnel experiment

“…Dust deposition is mostly parameterized through deposition velocity, w d , and in most dust-deposition experimental Wind Tunnel: Chamberlain (1967) Grass 0.7 Chamberlain (1967) Sticky grass 0.7 Clough (1973) Filter paper 0.24 Clough (1975) Dry tray 0.37-0.87 Clough (1975) Wet tray 0.37-0.87…”

The Relative Quantity of Airborne Plutonium Deposited in the Respiratory Tract and on the Skin of Rats

“…Since t h e deposi ti on v e l o c i t y o n t o h o r i z o n t a l s u r f a c e s increases from 4 x cm/sec t o 3 x 1 0 -I cm/sec as p a r t i c l e diameter f o r u n i t d e n s i t y spheres increases from 1 pm t o 10 Dm (Clough, 1973), and a l s o i n c r e a s e s as t h e wind v e l o c i t y i n c r e a s e s , t h e r e 1 a t i ve importance o f t h e m a t e r i a l depos i Led on t h e s k i n w i 11 vary w i t h p a r t i c l e s i z e and t h e wind v e l o c i t y . However, i t seems u n l i k e l y t h a t t h e s k i n d e p o s i t i o n would e v e r g r e a t l y exceed t h e t o t a l i n i t i a l d e p o s i t i o n i n t h e r e s p i r a t o r y t r a c t , s i n c e l a r g e r p a r t i c l e s w i l l s e t t l e o u t c l o s e t o t h e p o i n t o f emission.…”

“…The q u a n t i t y o f m a t e r i a l deposited on an exposed s u r f a c e ( Q s u r f a c e ) i s a f u n c t i o n o f t h e n a t u r e and o r i e n t a t i o n o f t h e surface (Clough, 1973), and o f t h e d e p o s i t i o n v e l o c i t y (V) o f t h e aerosol. The d e p o s i t i o n v e l o c i t y i s t h e r a t i o between r a t e o f t r a n s f e r o f m a t e r i a l from a i r t o a u n i t surface and the a i r concentration, i .e.…”