Concentration and vertical distribution of Aitken particles

We can characterize the particle concentration of an aerosol in two different ways. Firstly, the number concentration can be employed which is the number of the particles in a unit gas volume. Secondly, like the concentration of trace gases, the particle mass in a unit volume (mass concentration) can be given as we have seen in Chapter 3. In this subsection we will always use the number concentration of all particles which is practically equivalent to the number of Aitken size particles (see 

Subsection 4.1.2). All values discussed in the following were obtained using expansion chambers. 

The early results of particle concentration measurements carried out under different conditions were compiled by Landsberg (see Junge, 1963). Some of his data are reproduced in Table 18. The figures tabulated make it evident that the majority of particles are of continental origin. It is also obvious that man s activity plays an important role in particle production. Furthermore, one can see from Table 18 that the number concentration of atmospheric aerosol particles decreases with increasing height. 

Average concentration of Aitken particles under various conditions according to Landsberg (see Junge. 1963) 

It is questionable whether the higher values reported for the Northern Atlantic Ocean are caused by anthropogenic pollutant emissions. Unfortunately, it is very 

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