diff --git a/src/MNH/write_lfifm1_for_diag.f90 b/src/MNH/write_lfifm1_for_diag.f90
index a6099e6a0f4eb779347699adbcf1e6f85fc896ca..01c1c560e957fed8f28c7445895ae399ea2487da 100644
--- a/src/MNH/write_lfifm1_for_diag.f90
+++ b/src/MNH/write_lfifm1_for_diag.f90
@@ -1348,8 +1348,26 @@ IF ((LCHEMDIAG).AND.(LORILAM).AND.(LUSECHEM)) THEN
   IF (.NOT.(ASSOCIATED(XSIG3D))) &
     ALLOCATE(XSIG3D(SIZE(XSVT,1),SIZE(XSVT,2),SIZE(XSVT,3),JPMODE))
   !
-  CALL  PPP2AERO(XSVT(:,:,:,NSV_AERBEG:NSV_AEREND), XRHODREF, &
-                 PSIG3D=XSIG3D, PRG3D=XRG3D, PN3D=XN3D, PCTOTA=ZPTOTA)
+  IF (CRGUNIT=="MASS") THEN
+  XRG3D(:,:,:,1) = XINIRADIUSI * EXP(-3.*(LOG(XINISIGI))**2)
+  XRG3D(:,:,:,2) = XINIRADIUSJ * EXP(-3.*(LOG(XINISIGJ))**2)
+  ELSE
+  XRG3D(:,:,:,1) = XINIRADIUSI
+  XRG3D(:,:,:,2) = XINIRADIUSJ
+  END IF
+  XSIG3D(:,:,:,1) = XINISIGI
+  XSIG3D(:,:,:,2) = XINISIGJ
+  XN3D(:,:,:,1) = XN0IMIN
+  XN3D(:,:,:,2) = XN0JMIN
+  
+  ZPTOTA(:,:,:,:,:) = 0.
+
+  CALL  PPP2AERO(XSVT(IIB:IIE,IJB:IJE,IKB:IKE,NSV_AERBEG:NSV_AEREND),&
+                 XRHODREF(IIB:IIE,IJB:IJE,IKB:IKE), &
+                 PSIG3D=XSIG3D(IIB:IIE,IJB:IJE,IKB:IKE,:),&
+                 PRG3D=XRG3D(IIB:IIE,IJB:IJE,IKB:IKE,:),&
+                 PN3D=XN3D(IIB:IIE,IJB:IJE,IKB:IKE,:),& 
+                 PCTOTA=ZPTOTA(IIB:IIE,IJB:IJE,IKB:IKE,:,:))
 
   TZFIELD = TFIELDMETADATA(                   &
     CMNHNAME   = 'generic for aerosol modes', &