diff --git a/.homeychangelog.json b/.homeychangelog.json
index 9a14e1c..2d0d4cf 100644
--- a/.homeychangelog.json
+++ b/.homeychangelog.json
@@ -254,5 +254,9 @@
   "1.5.0": {
     "en": "Added OneCall API device for historical daily summary. Added instructions to pair view.",
     "de": "OneCall API Gerät für historische tägliche Zusammenfassung ergänzt. Anleitung für Greät-Hinzufügen-Dialog ergänzt"
+  },
+  "1.5.1": {
+    "en": "Fix for invalid air quality index.",
+    "de": "Korrektur für ungültigen Luftqqalitäts-Index."
   }
 }
diff --git a/.homeycompose/app.json b/.homeycompose/app.json
index 2810384..ef61070 100644
--- a/.homeycompose/app.json
+++ b/.homeycompose/app.json
@@ -1,6 +1,6 @@
 {
 	"id": "nu.baretta.openweathermap",
-	"version": "1.5.0",
+	"version": "1.5.1",
 	"compatibility": ">=8.1.1",
 	"sdk": 3,
 	"name": {
diff --git a/app.json b/app.json
index a38061d..65025f1 100644
--- a/app.json
+++ b/app.json
@@ -1,7 +1,7 @@
 {
   "_comment": "This file is generated. Please edit .homeycompose/app.json instead.",
   "id": "nu.baretta.openweathermap",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "compatibility": ">=8.1.1",
   "sdk": 3,
   "name": {
diff --git a/drivers/owmAirPollutionCurrent/device.js b/drivers/owmAirPollutionCurrent/device.js
index 9e3ebb2..9233e43 100644
--- a/drivers/owmAirPollutionCurrent/device.js
+++ b/drivers/owmAirPollutionCurrent/device.js
@@ -227,7 +227,12 @@ class owmAirPollutionCurrent extends Homey.Device {
         this.getDataCapability('measure_ap_so2')['value'] = data.list[0].components.so2;
         this.getDataCapability('measure_ap_nh3')['value'] = data.list[0].components.nh3;
         this.getDataCapability('measure_ap_aqi')['value'] = data.list[0].main.aqi.toString();
-        this.getDataCapability('measure_ap_aqi_nr')['value'] = data.list[0].main.aqi;
+        if (data.list[0].main.aqi < 1  || data.list[0].main.aqi > 5){
+            this.getDataCapability('measure_ap_aqi_nr')['value'] = undefined; 
+        }
+        else{   
+            this.getDataCapability('measure_ap_aqi_nr')['value'] = data.list[0].main.aqi;
+        }
 
         // CAPABILITIES: Compare values and update changed capabilities.
         // TRIGGER: Compare values to start trigger after capability update.
diff --git a/drivers/owmAirPollutionHourly/device.js b/drivers/owmAirPollutionHourly/device.js
index c379e79..aee5ba4 100644
--- a/drivers/owmAirPollutionHourly/device.js
+++ b/drivers/owmAirPollutionHourly/device.js
@@ -153,7 +153,12 @@ class owmAirPollutionHourly extends Homey.Device {
         this.getDataCapability('measure_ap_so2')['value'] = data.components.so2;
         this.getDataCapability('measure_ap_nh3')['value'] = data.components.nh3;
         this.getDataCapability('measure_ap_aqi')['value'] = data.main.aqi.toString();
-        this.getDataCapability('measure_ap_aqi_nr')['value'] = data.main.aqi;
+        if (data.main.aqi < 1  || data.main.aqi > 5){
+            this.getDataCapability('measure_ap_aqi_nr')['value'] = undefined; 
+        }
+        else{   
+            this.getDataCapability('measure_ap_aqi_nr')['value'] = data.main.aqi;
+        }
 
         // CAPABILITIES: Compare values and update changed capabilities.
         // TRIGGER: Compare values to start trigger after capability update.