diff --git a/examples/luftdaten.py b/examples/luftdaten.py
index b7f0565..5690e90 100755
--- a/examples/luftdaten.py
+++ b/examples/luftdaten.py
@@ -50,6 +50,7 @@
 
 # Read values from BME280 and PMS5003 and return as dict
 def read_values():
+    global pms5003
     values = {}
     cpu_temp = get_cpu_temperature()
     raw_temp = bme280.get_temperature()