diff --git a/include/payload.h b/include/payload.h
index 719d59ec..0f968df7 100644
--- a/include/payload.h
+++ b/include/payload.h
@@ -23,6 +23,7 @@
 #define LPP_HUMIDITY_CHANNEL 29
 #define LPP_BAROMETER_CHANNEL 30
 #define LPP_AIR_CHANNEL 31
+#define LPP_PARTMATTER_CHANNEL 32    // particular matter
 
 // MyDevices CayenneLPP 2.0 types for Packed Sensor Payload, not using channels,
 // but different FPorts