This study considers those plant species whose pollens present the greatest allergenic potential within our regions, namely: the birch tree, the Poaceae (Gramineae) and Ambrosia (ragweed). The study focuses on two well-documented regions in particular: the Lyon region and the Paris region. The study utilizes pollen-exposure data obtained via daily pollen counts carried out by volumetric sensors scattered throughout both regions. It compares the health-impact data estimated using the Journal Pollinique (“Pollen Hay Fever Diary”), a computing tool that allows its users to record their daily health in the form of “symptom scores”. Therefore, the main objective of this study is to compare pollen-exposure data with health-impact data, so as to establish the existence of any correlation between these two phenomena. In addition, by assessing the pertinence of the comparison system currently in use, the study also seeks to propose possible improvements to this system and to evoke its prospects and potential.