Assessing Associations Between Pollen Resilience Index Forecast Values and Allergic Health Symptoms Induced by Aeroallergens

Pollen is one of the primary aeroallergens that negatively impacts human health during the vegetation period. Studies have demonstrated that air pollution and meteorological factors influence the severity of airborne pollen load and modify its effects on health. The Pollen Resilience Index (PRI) is a five-point index developed by integrating CAMS air pollution and pollen forecast data within a framework of legal and scientific thresholds and Humidex index values. It ranges from 1 (no health effects observed in sensitive individuals) to 5 (pollen exposure, combined with environmental factors, causes adverse health effects). The forecasted PRI values indicate the potential severity of pollen exposure under varying environmental conditions.

In this study, we aimed to validate the PRI using retrospective, anonymised data collected from users of the PASYFO mobile application. The dataset comprised 9,472 symptom reports related to eye, nose, and lung symptoms from 247 participants. These responses were analysed to determine how PRI values correspond with symptom reporting. Sensitivity to airborne irritants and individuals’ ability to tolerate these effects varied considerably and were limited by personal health conditions, reporting habits, and symptom intensity. This variation introduced uncertainty into the results, complicating statistical analysis.

Our analysis revealed a strong and consistent tendency for participants to report symptoms when the PRI exceeded a value of 1. Specifically, as the PRI increased, the proportion of respondents reporting symptoms also rose. This effect was most prominent for eye and nose symptoms. For example, when the PRI was 1, 21.3% of participants reported eye and 31.1% reported nose symptoms. At the maximum PRI value of 5, the proportion of individuals reporting eye symptoms increased to 42.6%, while nose symptoms were reported by 58.7% of participants. Common symptoms, such as eye itching, watering, redness, runny nose, and sneezing, showed the most significant increase in reporting under higher PRI conditions. The effect on lung-related symptoms was less pronounced, although their reporting also increased with higher PRI levels. Respiratory symptoms, including shortness of breath and coughing, rose by less than 7% even under the worst conditions (PRI = 5). This suggests that while pollen exposure affects respiratory health, its correlation with lung symptoms is less direct compared to eye and nose symptoms.

Among the various types of pollen, Betula (birch) and Alnus (alder) were most closely associated with the development of allergic symptoms. This highlights the significance of specific pollen types in exacerbating allergic reactions. The findings underscore the value of using the PRI as a predictive tool to assess the potential health risks posed by aeroallergens and to help mitigate their impact on sensitive individuals. Our research demonstrates the effectiveness of integrating air quality, weather, and pollen data to create a tool for predicting the health impacts of aeroallergens.

This research was funded by the LMTLT agreement No. S-MIP-19-53 and supported by EO4EU, funded by the Horizon Europe RIA Programme under Grant Agreement No. 101060784.