An error in some of the plots of my data has forced me to do review all my data from scratch again. Somewhere in the process of transposing, copying & formatting my data an error occurred and some of my snow data ended up as air data.
I do not have tons of data, but enough to make things difficult, when it gets messed up. Since numbers are similar (though units are not) I did not easily recognise my mistake. Now everything should be fine again, but it took a while to re-calculate all concentrations (18 compounds, 7 days of monitoring, air & snow) and plot them again.
Here is, how things look like: Toluene concentrations in snow and air at Alert in May/June 2006! Note the depletion in snow and air on May 30, which I also observed for quite a few other compounds (though not for all). I currently investigate this event using my other data and model calculations.