diff --git a/definitions/other.xml b/definitions/other.xml
index 3f0ff04..a6b34d8 100644
--- a/definitions/other.xml
+++ b/definitions/other.xml
@@ -24,5 +24,13 @@
       <fraction n="0.954887" ref="I" />
    </material>
   
+<material name="LUNG20_AIR80 " state="solid">
+      <D unit="g/cm3" value="0.209" />
+      <fraction n="0.20" ref="G4_LUNG_ICRP " />
+      <fraction n="0.80" ref="G4_AIR" />
+   </material>
+
+
 
+   
 </materials>