diff --git a/pyaerocom/io/read_airnow.py b/pyaerocom/io/read_airnow.py
index c4dd16617..029c08a73 100644
--- a/pyaerocom/io/read_airnow.py
+++ b/pyaerocom/io/read_airnow.py
@@ -402,7 +402,11 @@ def _filedata_to_statlist(self, arrs, vars_to_retrieve):
             mask = data[:, varcol] == var_in_file
             subset = data[mask]
             dtime_subset = dtime[mask]
-            statlist = np.unique(subset[:, statcol])
+            # not all stations seems to provide the station id as string...
+            try:
+                statlist = np.unique(subset[:, statcol])
+            except TypeError:
+                statlist = np.unique(str(subset[:, statcol]))
             for stat_id in tqdm(statlist, desc=var):
                 if not stat_id in stat_ids:
                     continue