Possible bug in area_classification/station_classification for EBAS-EMEP stations (v. 1.5)

Hi @dbowdalo,

it looks like there might be a bug affecting the metadata of some EBAS-EMEP stations. Specifically, several sites that are rural regional stations appear in the files with an "urban-suburban" value in area_classification, and "nan" in station_classification.

For example, the stations ES0013R, ES0016R, and ES0006R show this issue (observed in the hourly file sconcno2_201609.nc).

Many thanks!