Table 3 Meta-analyzed relative risk estimates of allergy medication fills and allergic rhinitis physician visits (first visit in calendar year) on days designated as – (i) ‘high’ pollen level based on same day imputed values, (ii) ‘high’ pollen based on 7-day average of imputed values; (iii) ‘high’ pollen based on same day non-imputed values of pollen (with missing pollen observations), (iv) days with pollen concentrations >=75^th percentile of the pollen distribution during the study period. ’High’ pollen level is defined by pollen concentrations (grains/m³) – 250 < Tree < 1500; 50 < grass < 100, 100 < weed < 250. Relative risk estimates derived from models with weekly ILI index, air pollution measures (daily PM2.5 and Ozone) and meteorological factors (daily maximum temperature, total precipitation, and average wind speed) as covariates

From: Short term physician visits and medication prescriptions for allergic disease associated with seasonal tree, grass, and weed pollen exposure across the United States