Measurements of the optical properties of the smoke emissions from plastics,hydrocarbons, and other urban fuels for nuclear winter studies

We have measured the optical and microphysical properties of smoke from burning plastic materials and other components of the urban fuel mix, including hydrocarbons, rubber, and wood, to provide information on the source term for possible aerosol clouds injected into the atmosphere following large scale urban fires. Our measurements included measurements of emission factors; in situ optical measurements of aerosol absorption, scattering, and attenuation; and collection of particles using both filters and cascade impactors for size and mass concentration determinations.These measurements were made under a variety of conditions to investigate the range of variation of these optical parameters and to relate observed differences in smoke properties to differences in fuel composition and fire conditions.The plastic data show average B_e values near 10 m² g⁻¹ at 488 nm and 8 m² g⁻¹ at 633 nm. Values of B_e measured during smoldering combustion are significantly less than in flaming combustion. Flaming combustion B_e values for the rubber appear to be somewhat higher, particularly for the tire rubber; petroleum product fuel values are comparable to the plastic fuel values; and oak smoke emissions values are slightly lower than the plastic values. Measured 633 nm B_a values were approximately 6 m² g⁻¹ for the petroleum products, 7 m² g⁻¹ for the rubber, 6 m² g⁻¹ for the wood, and 6 m² g⁻¹ for the plastic.