Pollen from weeds and bushes may be very allergenic. The distribution of these plants differs among geagraphical areas.
For example, Ambrosia (Ragweed), one of the most allergenic, is widely distributed in USA and some limited areas in Europe, but not in Spain. In the Mediterranean coast of Spain are found the very allergenic Parietaria and Salsola, as well as Chenopodium. Their pollen season of these latter range from May to October.
By clicking on the draw you may access to the pollen counts of the allergenic plants in different cities of Spain.