Fig. 1
Variability of Urtica leaf pollen density over distance. Comparison between the three scenarios of the EFSA Panel model [4] and the empirically based findings of Hofmann et al. [3]. 
RS ‘realistic’ mean dose–distance relationship leaf pollen density Urtica [3]; 
WC ‘worst case’ scenario upper 95% CI leaf density data [3]; 
lower 95% CI leaf density data [3]; 
mean leaf pollen density Urtica per site during flowering period by standardized and calibrated PMF measurements (n = 214) with 95% confidence interval for single values [3]; 
95% CI for mean leaf pollen density Urtica per site per standardized and calibrated PMF measurements [3]; 
leaf pollen density data Urtica close to the pollen source indicating the variability and used for calibration (n = 836 measurement data, scattered around 0.2 m distance for displaying the variability close to source) [3]; 
DC—‘direct comparision’ scenario EFSA panel model 2015 [4]; 
MR—‘most realistic’ EFSA 2015 model [4]; 
CO—‘conservative’ EFSA 2015 model worst case 1:40 [4]; 
Difference between ‘MR—most realistic’ scenario EFSA 2015 [4] and ‘RS—realistic mean’ regression [3]: ratio 0.0138; 
Difference between ‘CO—conservative’ scenario EFSA 2015 [4] for 1:40 worst case and respective ‘WC—worst case’ [3]: ratio 0.00273; 
Difference between ‘DC—direct comparison’ EFSA 2015 [4] and ‘RS—realistic mean’ regression [3] based on measurement data: ratio 0.368