Reactions of Carbonaceous Smoke Particles with Atmospheric Ozone

Abstract

Large quantities of carbonaceous smoke particles are expected to be lofted into the upper troposphere and lower stratosphere as a result of massive fires accompanying an exchange of nuclear explosions. These smoke particles can be expected to chemically react with various reactive species in the ambient atmosphere, thereby scavenging the smoke and affecting the balance of atmospheric chemistry. Of particular interest is the reaction of the smoke particles with ozone, because of the abundance of the latter relative to the amount of smoke assumed to be generated in various nuclear war scenarios. A laboratory apparatus has been constructed to examine the reaction of smoke particles with ozone. Smoke has been generated in a burner and collected from forest fires by airborne sampling. Buoyant smoke particles are passed into two parallel reactor tubes. These reactors differ by the presence or absence of ozone in the flow. The time course of the transmission of light through these two smoke columns provides a measure of the stability and reactivity of the smoke with and without ozone. Smoke particles are also deposited on sized filters for examination with the scanning electron microscope. Some results are reported on smoke particles collected from laboratory burner flames and from a prescribed forest fire in the Lodi Canyon, Los Angeles, CA.