Soot, dust, occasionally industrial pollution and even dust from the Sahara are sometimes or often found as inorganic floating particles in the ‘Burkard’ pollen-and-spore trap. The time of their occurrence can be determined fairly accurately, as 2 mm of the exposed tape corresponds to one hour. It is possible to evaluate this kind of aerial pollution semiquantitatively with photometric equipment for electropherograms found at every modern hospital. In addition the flowering calendars of two places with very differing climate are shown (Basle and Davos). Therefore, several years of pollen collection can be compared. In the mountains there are fewer pollen grains and also grains of not so many species. But there are also fewer inorganic particles in the air of Davos than in a city such as Basle.