diff --git a/src/specificClass.js b/src/specificClass.js
index a240275..81ba36b 100644
--- a/src/specificClass.js
+++ b/src/specificClass.js
@@ -254,6 +254,16 @@ class Reactor_PFR extends Reactor {
     return stateNew;
   }
 
+  updateMeasurement(variant, subType, value, position) {
+    switch(subType) {
+      case "oxygen":
+        grid_pos = Math.round(position * this.n_x);
+        this.state[grid_pos][S_O_INDEX] = value; // naive approach for reconciling measurements and simulation
+        return;
+    }
+    super.updateMeasurement(variant, subType, value, position);
+  }
+
   /**
    * Apply boundary conditions to the reactor state.
    *  for inlet, apply generalised Danckwerts BC, if there is not flow, apply Neumann BC with no flux