Supplementary Material for: Impact of meteorological parameters and air pollutants on weed pollen-induced allergic rhinitis symptoms in Dalian, China

In recent years, coastal cities like Dalian have experienced a notable rise in pollen-induced allergic rhinitis (PiAR). This trend highlights the urgent need to investigate how climatic changes and air pollution exacerbate this growing public health challenge. This study examines the combined effects of meteorological variables, air pollutants, and airborne pollen on weed PiAR symptoms in Dalian, a coastal city located in the warm temperate zone of China. Methods: Daily pollen concentrations were monitored from August to October 2023, concurrently with meteorological data and air quality indices. Clinical data, including symptoms and fractional exhaled nitric oxide (FENO) levels, were collected from 61 PiAR patients to evaluate the impact of environmental factors on allergy severity and airway inflammation. Results: Among meteorological variables, temperature exhibited a positive influence on the concentrations of total pollen, specifically that of Artemisia, Humulus, and Chenopodium pollen, while air pressure showed an inverse relationship. Regarding air pollutants, O3 concentration was positively associated with Artemisia pollen levels, whereas CO and NO2 were negatively associated. Statistical analysis demonstrated a strong positive correlation between daily weed pollen concentrations and the Combined Symptom and Medication Score (CSMS) (r = 0.81, p < 0.0001), as well as between weekly average pollen concentrations and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score (r = 0.95, p < 0.0001). Pollen exposure showed a significant immediate effect on CSMS at lag 0 (EE = 0.205, 95% CI: 0.076–0.334), while air pressure exhibited significant lagged and cumulative effects during lag days 0–5 (EE = 0.815, 95% CI: 0.337–1.293). Notably, the interaction between temperature and air pressure was also statistically significant (p < 0.001). Additionally, FENO levels in PiAR patients significantly rose during the peak weed pollen season (p < 0.001), indicating elevated airway inflammation. Conclusion: This study highlights the complex interplay between meteorological factors, air pollutants, and pollen in exacerbating allergic symptoms. The findings underscore the need for integrated environmental and clinical management strategies to mitigate the burden of PiAR in urban settings.