Erratum to: Environ Sci Eur (2017) 29:12 DOI 10.1186/s12302-017-0106-0

Upon publication of the original article [1], it was noticed that in the HTML version, two signs in the captions of Fig. 1 were the wrong way round.

The grey circle: should denote ‘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).’

The pink dotted line: should denote ‘DC—‘direct comparison’ scenario EFSA panel model 2015’.

This has now been updated in the original HTML version of the article. This error arose due to our systems not processing the authors’ original correction request, therefore we, the publishers, apologise for this error and any inconvenience caused by it.