Pollutants: Fix delete sql request.

src/Model/Pollutants/PollutantsList.py

@@ -38,7 +38,10 @@ class PollutantsList(PamhyrModelList):
         ok = True
 
         # Delete previous data
-        execute("DELETE FROM Pollutants")
+        execute(
+            "DELETE FROM Pollutants " +
+            f"WHERE scenario = {self._status.scenario_id}"
+        )
 
         for sl in self._lst:
             ok &= sl._db_save(execute, data)