Fig. 3

Predicted marginal effects (proportions) of significant interactions between birch pollen levels (below or above 100 grains /m3) and pollutants (per µg/m3) on symptoms and allergy medication usage. Footnote: For eye irritation/rhinitis, dyspnea and allergy medication, “Yes” vs. “No”. X-axis from 5th to 95th percentile. Results are from mixed models with identification number and city as a random effect. In addition to pairwise combinations of air pollution and pollen concentration indicator at lag 0–2, the models are adjusted for temperature and relative humidity. Results are reported per global pollutant IQR (NOx 16.4 µg/m3, O3 15.2 µg/m3, PM2.5 4.7 µg/m3)