Easy-to-use field instrument for assessing air quality using lichens

Lichens serve as bioindicators. The species composition provides information about air quality. Mapping lichens on trees by compass direction has not yet been possible without limitations using digital technology. With a new app, a Python-based script, lichens can now be mapped on every smart device according to compass direction. Locations and various parameters can be documented on a map and in tables. The app can be combined with an external macro camera, digital microscope, or label printer for samples for documentation purposes. External data processing can be performed using an SQLite database or CSV tables. An evaluation of Ellenberger's indicator values according to Wirth (2010) for lichens and air quality according to VDI-3957 can already be carried out directly in the field. This means that the results can be discussed on site. For practitioners, this is helpful and opens up new possibilities for teaching. For beginners, the app currently includes a short guide to identifying lichens and a quick search for species. Depending on further configuration, the app can be used for official air quality reports or educational institutions.