diff --git a/environmental_measurement.proto b/environmental_measurement.proto
index 64d73a0..6a7d090 100644
--- a/environmental_measurement.proto
+++ b/environmental_measurement.proto
@@ -6,5 +6,5 @@ message EnvironmentalMeasurement {
   float temperature = 1;
   float relative_humidity = 2;
   float barometric_pressure = 3;
-
+  float gas_resistance = 4;
 }