diff --git a/src/main.cpp b/src/main.cpp
index b5bf0a7..8f73c9f 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -51,15 +51,15 @@ XD0OTA ota("esp32-weatherstation");
 XD0MQTT mqtt;
 
 struct __attribute__((packed)) sensor_readings_t {
-  float temperature = 0.0; // °C
-  float humidity = 0.0; // %H
-  float pressure = 0.0; // Pa
+  float temperature = NAN; // °C
+  float humidity = NAN; // %H
+  float pressure = NAN; // Pa
   uint32_t voc = 0; // Ohm
-  float pm10 = 0.0; // µg/m³
-  float pm25 = 0.0; // µg/m³
-  float uvi = 0.0;
-  float uva = 0.0;
-  float uvb = 0.0;
+  float pm10 = NAN; // µg/m³
+  float pm25 = NAN; // µg/m³
+  float uvi = NAN;
+  float uva = NAN;
+  float uvb = NAN;
   float temperature_max = NAN; // °C
   float temperature_min = NAN; // °C
 } sensor_readings;
@@ -266,18 +266,18 @@ void displayValues() {
     if (sds_active) {
       pm10 = sensor_readings.pm10;
       pm25 = sensor_readings.pm25;
-    } else if (std::isnormal(sensors_a4cf1211c3e4.pm10) || std::isnormal(sensors_a4cf1211c3e4.pm25)) {
+    } else if (!isnan(sensors_a4cf1211c3e4.pm10) || !isnan(sensors_a4cf1211c3e4.pm25)) {
       pm10 = sensors_a4cf1211c3e4.pm10;
       pm25 = sensors_a4cf1211c3e4.pm25;
-    } else if (std::isnormal(sensors_246f28d1fa5c.pm10) || std::isnormal(sensors_246f28d1fa5c.pm25)) {
+    } else if (!isnan(sensors_246f28d1fa5c.pm10) || !isnan(sensors_246f28d1fa5c.pm25)) {
       pm10 = sensors_246f28d1fa5c.pm10;
       pm25 = sensors_246f28d1fa5c.pm25;
-    } else if (std::isnormal(sensors_246f28d1a080.pm10) || std::isnormal(sensors_246f28d1a080.pm25)) {
+    } else if (!isnan(sensors_246f28d1a080.pm10) || !isnan(sensors_246f28d1a080.pm25)) {
       pm10 = sensors_246f28d1a080.pm10;
       pm25 = sensors_246f28d1a080.pm25;
     } else {
-      pm10 = 0.0;
-      pm25 = 0.0;
+      pm10 = NAN;
+      pm25 = NAN;
     }
     display.setCursor(200,y_offset+45);
     display.println("PM10 / 2.5:");
@@ -291,22 +291,22 @@ void displayValues() {
       uvi = sensor_readings.uvi;
       uva = sensor_readings.uva;
       uvb = sensor_readings.uvb;
-    } else if (std::isnormal(sensors_a4cf1211c3e4.uvi) || std::isnormal(sensors_a4cf1211c3e4.uva) || std::isnormal(sensors_a4cf1211c3e4.uvb)) {
+    } else if (!isnan(sensors_a4cf1211c3e4.uvi) || !isnan(sensors_a4cf1211c3e4.uva) || !isnan(sensors_a4cf1211c3e4.uvb)) {
       uvi = sensors_a4cf1211c3e4.uvi;
       uva = sensors_a4cf1211c3e4.uva;
       uvb = sensors_a4cf1211c3e4.uvb;
-    } else if (std::isnormal(sensors_246f28d1fa5c.uvi) || std::isnormal(sensors_246f28d1fa5c.uva) || std::isnormal(sensors_246f28d1fa5c.uvb)) {
+    } else if (!isnan(sensors_246f28d1fa5c.uvi) || !isnan(sensors_246f28d1fa5c.uva) || !isnan(sensors_246f28d1fa5c.uvb)) {
       uvi = sensors_246f28d1fa5c.uvi;
       uva = sensors_246f28d1fa5c.uva;
       uvb = sensors_246f28d1fa5c.uvb;
-    } else if (std::isnormal(sensors_246f28d1a080.uvi) || std::isnormal(sensors_246f28d1a080.uva) || std::isnormal(sensors_246f28d1a080.uvb)) {
+    } else if (!isnan(sensors_246f28d1a080.uvi) || !isnan(sensors_246f28d1a080.uva) || !isnan(sensors_246f28d1a080.uvb)) {
       uvi = sensors_246f28d1a080.uvi;
       uva = sensors_246f28d1a080.uva;
       uvb = sensors_246f28d1a080.uvb;
     } else {
-      uvi = 0.0;
-      uva = 0.0;
-      uvb = 0.0;
+      uvi = NAN;
+      uva = NAN;
+      uvb = NAN;
     }
     display.setCursor(200,y_offset+85);
     display.println("UV Index/A/B:");
@@ -532,12 +532,9 @@ void loop()
     lastDisplayUpdate = millis();
 
     getSensorMeasurements();
-
     displayValues();
-
     printValues();
     sendValues();
-
   }
 
   if(wifiMulti.run() != WL_CONNECTED) {