Accumulation mode size distributions ambient

For example, Fig. 9.23a shows the measured volume distribution of one ambient aerosol sample. When this volume distribution is multiplied by the size distribution of the scattering coefficient per unit volume in Fig. 9.22, one obtains the calculated curve for light scattering in Fig. 9.23b. It is seen that the particles in the 0.1-to 1-yu.m-diameter range, that is, in the accumulation mode, are clearly expected to predominate the light scattering. 

THE AMBIENT ATMOSPHERIC AEROSOL consists of liquid and solid particles that can persist for significant periods of time in air. Generally, most of the mass of the atmospheric aerosol consists of particles between 0.01 and 100 xm in diameter distributed around two size modes a coarse or mechanical mode centered around 10- to 20- xm particle diameter, and an accumulation mode centered around 0.2- to 0.8- xm particle diameter (1). The former is produced by mechanical processes, often natural in origin, and includes particles such as fine soils, sea spray, pollen, and other materials. Such particles are generated easily, but they also settle out rapidly because of deposition velocities of several centimeters per second. The accumulation mode is dominated by particles generated by combustion processes, industrial processes, and secondary particles created by gases converting to par-... 

---