Planning prescribed fires for optimal periods which results in emissions reduction is an extremely useful air quality management technique. New information suggests that one more useful tool in smoke management may involve using the capacity of the atmosphere to remove smoke particles. Smoke particles have been observed to be very efficient cloud condensation nuclei. Hence, when smoke particles are introduced into air masses of sufficient moisture content, clouds form and in some cases precipitation can be initiated. We have measured the smoke entering and leaving small cumulus clouds and find that while these clouds are not very effective in removing the accumulation mode aerosol (0.1 to 2 um) they do remove nearly all of the super-micron aerosol. However, for large cumulus clouds we have obtained data showing very significant scavenging of all but the smallest aerosol, removing 40 to 80% of the accumulation mode and approaching 100% removal of the supermicron mode particles. Cloud scavenging of smokes from biomass fires is a mechanism that should be considered in prescribing fires for wildland management purposes. Prescriptions that now minimize the emissions through reducing the total fuel consumption may need to be modified to provide for additional heat release to facilitate cumulus cloud formation or be scheduled to utilize naturally occurring clouds. © by the Society of American Foresters. Abstract reproduced by permission.