e observational evidence indicates that recent re-gional changes in climate,particularly temperature increases, have already a ected a diverse setof phy-sical and biological systems in many parts of the world. Allergens patterns are also changing in res-ponse to climate change and air pollution can mo-dify the allergenic potential of pollen grains espe-cially in the presence of speci c weather conditions. Although genetic factors are important in the de-velopment of asthma and allergic diseases, their ri-sing trend can be explained only by changes occur-ring in the environment and urban air pollution by motor vehicles has been indicated as one of the ma-jor risk factors responsible for this increase