Most organisms live in inevitable dependence on the ambient air. Due to the worldwide increase of pollutants in the atmosphere, the protection of the air envelope has become perhaps the most important issue of our time. Extensive laws and regulations are designed to maintain and improve existing air quality, as its purity is essential and even minimal changes can have far-reaching consequences. However, for reasons of cost, actual controls of contamination only take place on a selective basis. At present, only a few statements can be made about large-scale contaminant emissions or contaminant sources involved. Conifers have already proven their worth as passive collectors and bioindicators in many cases. Compared to air filters, which require complicated installation, pine needles offer considerable advantages.