**3. Results**

#### *3.1. Analysis of Particle Number (PN) Distribution in Wroclaw and Cracow*

The obtained results were analysed in terms of the type of air pollution immission source. They were divided into transportation, household, and point sources of immission. The analysis has shown that for all measurements performed (irrespective of the source of immission), particulate matter occurred in the whole measurement range, i.e., 0.34–10.00 μm (Table 1). The highest results (irrespective of immission source) were obtained during morning measurement in Wroclaw. The graphs show the results obtained during two measurements (a morning one and an afternoon one) from each type of immission source. Figure 1 shows the characteristics of the particles number concentration as a function of their size (dN/dlogDp).


**Table 1.** Detailed results of PN distribution in Wroclaw and Cracow.

A more detailed description is provided in Figure 2 which is showing the percentage share of each particle diameter in the test in each type of immission source. The green color indicates the shares up to 5%, yellow the range between 5% and 50%, and red above 50%. Additionally, the range of the diameter of the largest particles number, and the share of particles with a diameter smaller than 1 μm, are shown in Table 1.

**Figure 1.** Particle number (PN) distributions in Wroclaw and Cracow.


**Figure 2.** Percentage of particles number by their size in tests (all sectors).
