Although pollen allergy is the most frequent allergic disease in countries with a western life style (1), knowing "the enemy" i.e. the current pollen exposure, is still a neglected scientific topic. This is remarkable, as pollen levels predict allergy symptoms in allergic individuals (2). In addition, higher pollen exposure results in more allergic sensitizations (3). Thus, knowing the local pollen count is of relevance for allergic individuals. Instrumental to the measurement of ambient pollen was the development of the manual Hirst trap in 1952, a simple and cheap but efficient instrument able to assess airborne pollen. And indeed, pollen is now monitored in almost every country of the world with this instrument (4), with some time series dating back to 1952.