No abstract

No abstract

Simultaneous measurements of the vertical profiles of horizontal wind, temperature, and ozone concentration above a bare, freshly cultivated fine sandy loam were obtained on 12 occasions during a 4-day period in July when ozone concentrations ranged from 8 to 26 X 10 z molecules (mol) -3 (1X 101~ tool cm =3 ---4 ppb = 8/~g m-3). The decrease in ozone near the soil surface clearly indicated that the soil was removing ozone from the atmosphere. The rate of ozone removal varied from 3 to 12 )< 10~z mol cm -2 sec -~. The flux into the soil varied with the concentration of ozone in the air, and indicated a resistance of about 2 sec cm -z to ozone removal bythe soil and the 2.5-cm air layer immediately above the soil. The rapid removal of ozone by soil in a ventilated chamber suggested a small resistance in the soil alone. A sample of soil containing 14% moisture had a resistance of 0.37 sec cm-ito ozone removal, which was 0.23 sec cm -1 greater than that of activated charcoal, a strong adsorbing agent. Compaction and additional soil moisture increased the resistance to ozone removal, whereas autoclaving decreased the resistance. Additional Index Words: resistance to ozone removal.Q --(Ca -Cb)/ra -b.[ 1 ]Since ra -bcombines the resistances of both the boundary layer and the soil itself, its magnitude can be reduced 1Contribution from the

No abstract

The removal of ozone from the air by bean leaves is regulated by the same factors that control the exchange of water vapor between leaves and the atmosphere.