Abstract
The effects of fine- particle Carbon, such as diesel soot, on the optical properties of urban haze in the visible wavelength range were explored to determine the dominant effects and to see if simple parameters (such as visual range in green) provide an adequate measure of these effects. It is shown that absorbing aerosol will darken the horizon sky, and a simple equation for the radiance of the horizon sky is derived. The effect of absorbing aerosol on the distance at which white and black objects can be seen is calculated.