Around twelve million people in Germany who are allergic to pollen rely on up to date information about the pollen count situation so that they can take countermeasures in good time. However, to date because of the technology used the forecasts have been based on measured data from the previous day. To change this, scientists from two Fraunhofer Institutes and from Albert-Ludwigs University in Freiburg in collaboration with equipment developers have developed an innovative automatic pollen monitor within the framework of the “OMNIBUSS” project. The German Weather Service, Deutsche Wetterdienst, has taken control.
In the past there were no efficient or reliable methods of forecasting pollen count. Measured pollen values are still determined through manual sampling and a subsequent visual evaluation of the samples in the laboratory. Microscopes are used to determine the pollen count, while cell cultures are used to define the spores. These methods are very time and personnel intensive and, in some cases, imprecise. Compared to this, fully automatic pollen measuring instruments provide a more up to date, accurate and cheaper way of gathering the data.
As the OMNIBUSS project, funded by the German Federal Ministry of Education and Research, started in 2003 scientists at the participating facilities set themselves the task of developing a stable analysis system with which airborne aerosols can be identified and analyzed. The focus was to be on inhalative, allergenic bioaerosols such as pollen and spores. The project has now produced a finished product: The MICROBUS bioaerosol monitor is scheduled to come on to the market this year.
Like conventional methods the automatic pollen monitor is based on microscopic analysis of the pollen that is gathered. However, this does not have to be analyzed by a skilled person; it is identified immediately on-site by means of an automatic sample identification method. To do this, dust and the pollen it contains are sucked from the ambient air and separated on a surface where they can be analyzed microscopically. To enable the pollen to be distinguished from the other dust particles the characteristic autofluorescence of the pollen is stimulated with help of fluorescence microscopy. Section by section a CCD camera takes a stack of high resolution images in fluorescent light. With the help of this tomographical method a three-dimensional reconstruction of the pollen grain is created from the images of the individual layers. Based on the shape and the inner structure a software program then classifies the objects in a complex image recognition method and allocates them to the individual types of allergenic pollen. The self-learning classification software can also be trained to identify pollen from potentially transgenic plants and other biological particles, such as fungal spores. Besides identifying the shape, the system counts the pollen and is thus able to draw conclusions about the respective concentration in the air.
Through the use of the new device it can be assumed that there will be a marked increase in the current 800 measuring stations worldwide. The measuring instrument could also be used to determine spore load on buildings. It is also conceivable that it could be used in the area of crop protection, in terms of intelligent pest control.