diff --git a/Adafruit_Sensor.h b/Adafruit_Sensor.h
index c18489f..b0169d8 100755
--- a/Adafruit_Sensor.h
+++ b/Adafruit_Sensor.h
@@ -138,9 +138,10 @@ typedef struct {
     float current;           /**< current in milliamps (mA) */
     float voltage;           /**< voltage in volts (V) */
     float tvoc;              /**< Total Volatile Organic Compounds, in ppb */
-    int32_t voc_index; /**< VOC (Volatile Organic Compound) index where 100 is
-                          normal */
-    int32_t nox_index; /**< NOx (Nitrogen Oxides) index where 100 is normal */
+    float voc_index; /**< VOC (Volatile Organic Compound) index where 100 is
+                          normal (unitless) */
+    float nox_index; /**< NOx (Nitrogen Oxides) index where 100 is normal
+                          (unitless) */
     sensors_color_t color; /**< color in RGB component values */
   };                       ///< Union for the wide ranges of data we can carry
 } sensors_event_t;
diff --git a/README.md b/README.md
index 293bd4b..1e87bed 100644
--- a/README.md
+++ b/README.md
@@ -141,8 +141,8 @@ typedef struct
         float           current;
         float           voltage;
         float           tvoc;
-        int32_t         voc_index;
-        int32_t         nox_index;
+        float           voc_index;
+        float           nox_index;
         sensors_color_t color;
     };
 } sensors_event_t;