Good preservation and storage of birch pollen (Betula verrucosaEhrh.) is desirable for two reasons; for one it enables a deeper knowledge of the biological state of the pollen and for the other, since birch pollen is a bio-indicator of air quality, its study under optimal conditions (preservation and biological state) at the biological, structural, ionic and immunological level is essential for analysing the effect of atmospheric pollution on the pollen. For this reason this study has involved both pollen collected under natural conditions and pollen from urban sites (in situ). For a period of two and half years we have studied different methods of preservation and different storage temperatures byin vitrogermination tests on a 10% sucrose Heslop-Harrison medium using rehydrated pollen. The best preservation is obtained with freeze-drying for half an hour and subsequent storage at 80°C. Thein vitrogermination test onin situpollen shows that the germination percentage is a reliable parameter for estimating the impact of atmospheric pollution on pollen because it varies in accordance with the degree of pollution at the urban sites.