diff --git a/meshtastic/telemetry.proto b/meshtastic/telemetry.proto
index 3661b28..ac4cd98 100644
--- a/meshtastic/telemetry.proto
+++ b/meshtastic/telemetry.proto
@@ -69,6 +69,71 @@ message EnvironmentMetrics {
   float current = 6;
 }
 
+/*
+ * Air quality metrics
+ */
+ message AirQualityMetrics {
+  /*
+   * Concentration Units Standard PM1.0
+   */
+  uint32 pm10_standard = 1;
+
+  /*
+   * Concentration Units Standard PM2.5
+   */
+  uint32 pm25_standard = 2;
+
+  /*
+   * Concentration Units Standard PM10.0
+   */
+  uint32 pm100_standard = 3;
+
+  /*
+   * Concentration Units Environmental PM1.0
+   */
+  uint32 pm10_environmental = 4;
+
+  /*
+   * Concentration Units Environmental PM2.5
+   */
+  uint32 pm25_environmental = 5;
+
+  /*
+   * Concentration Units Environmental PM10.0
+   */
+  uint32 pm100_environmental = 6;
+
+  /*
+   * 0.3um Particle Count
+   */
+  uint32 particles_03um = 7;
+
+  /*
+   * 0.5um Particle Count
+   */
+  uint32 particles_05um = 8;
+
+  /*
+   * 1.0um Particle Count
+   */
+  uint32 particles_10um = 9;
+
+  /*
+   * 2.5um Particle Count
+   */
+  uint32 particles_25um = 10;
+
+  /*
+   * 5.0um Particle Count
+   */
+  uint32 particles_50um = 11;
+
+  /*
+   * 10.0um Particle Count
+   */
+  uint32 particles_100um = 12;
+}
+
 /*
  * Types of Measurements the telemetry module is equipped to handle
  */
@@ -92,11 +157,16 @@ message Telemetry {
      * Weather station or other environmental metrics
      */
     EnvironmentMetrics environment_metrics = 3;
+
+    /*
+     * Air quality metrics
+     */
+    AirQualityMetrics air_quality_metrics = 4;
   }
 }
 
 /*
-* TODO: REPLACE
+* Supported I2C Sensors for telemetry in Meshtastic
 */
 enum TelemetrySensorType {
   /*
@@ -163,5 +233,9 @@ enum TelemetrySensorType {
   * High accuracy temperature and humidity
   */
   SHT31 = 12;
-  
+
+  /*
+   * PM2.5 air quality sensor
+   */
+  PMSA003I = 13;
 };