diff --git a/parm/aero/obs/config/viirs_n20_aod.yaml.j2 b/parm/aero/obs/config/viirs_n20_aod.yaml.j2
index c89e9f789..7806a4cd0 100644
--- a/parm/aero/obs/config/viirs_n20_aod.yaml.j2
+++ b/parm/aero/obs/config/viirs_n20_aod.yaml.j2
@@ -28,11 +28,18 @@
   obs filters:
     - filter: PreQC
       maxvalue: 1
+    - filter: Domain Check
+      where:
+      - variable:
+          name: latitude@MetaData
+        minvalue: -60
+        maxvalue: 60
     - filter: Bounds Check
       filter variables:
       - name: aerosolOpticalDepth
         channels: 4
       minvalue: 0
+      maxvalue: 4.9
       action:
         name: reject
     - filter: Background Check
diff --git a/parm/aero/obs/config/viirs_n21_aod.yaml.j2 b/parm/aero/obs/config/viirs_n21_aod.yaml.j2
new file mode 100644
index 000000000..6450ad9ec
--- /dev/null
+++ b/parm/aero/obs/config/viirs_n21_aod.yaml.j2
@@ -0,0 +1,50 @@
+- obs space:
+    name: viirs_n21_aod
+    obsdatain:
+      engine:
+        type: H5File
+        obsfile: "{{ DATA }}/obs/{{ OPREFIX }}viirs_n21.{{ current_cycle | to_YMDH }}.nc4"
+    obsdataout:
+      engine:
+        type: H5File
+        obsfile: "{{ DATA }}/diags/diag_viirs_n21_{{ current_cycle | to_YMDH }}.nc4"
+    io pool:
+      max pool size: 1
+    simulated variables: [aerosolOpticalDepth]
+    channels: 4
+  get values:
+    interpolation method: barycentric
+    time interpolation: linear
+  obs operator:
+    name: AodCRTM
+    Absorbers: [H2O,O3]
+    obs options:
+      Sensor_ID: v.viirs-m_j2
+      EndianType: little_endian
+      CoefficientPath: "{{ DATA }}/crtm/"
+      AerosolOption: aerosols_gocart_default
+  obs error:
+    covariance model: diagonal
+  obs filters:
+    - filter: PreQC
+      maxvalue: 1
+    - filter: Domain Check
+      where:
+      - variable:
+          name: latitude@MetaData
+        minvalue: -60
+        maxvalue: 60
+    - filter: Bounds Check
+      filter variables:
+      - name: aerosolOpticalDepth
+        channels: 4
+      minvalue: 0
+      maxvalue: 4.9
+      action:
+        name: reject
+    - filter: Background Check
+      channels: 4
+      threshold: 3.0
+      action:
+        name: inflate error
+        inflation factor: 3.0
diff --git a/parm/aero/obs/config/viirs_npp_aod.yaml.j2 b/parm/aero/obs/config/viirs_npp_aod.yaml.j2
index 90cacea7b..72efb740d 100644
--- a/parm/aero/obs/config/viirs_npp_aod.yaml.j2
+++ b/parm/aero/obs/config/viirs_npp_aod.yaml.j2
@@ -28,11 +28,18 @@
   obs filters:
     - filter: PreQC
       maxvalue: 1
+    - filter: Domain Check
+      where:
+      - variable:
+          name: latitude@MetaData
+        minvalue: -60
+        maxvalue: 60
     - filter: Bounds Check
       filter variables:
       - name: aerosolOpticalDepth
         channels: 4
       minvalue: 0
+      maxvalue: 4.9
       action:
         name: reject
     - filter: Background Check
diff --git a/parm/aero/obs/lists/gdas_aero.yaml.j2 b/parm/aero/obs/lists/gdas_aero.yaml.j2
index ae3b89fe7..238ba4856 100644
--- a/parm/aero/obs/lists/gdas_aero.yaml.j2
+++ b/parm/aero/obs/lists/gdas_aero.yaml.j2
@@ -2,4 +2,5 @@ observers:
 {% filter indent(width=2) %}
 {% include 'aero/obs/config/viirs_n20_aod.yaml.j2' %}
 {% include 'aero/obs/config/viirs_npp_aod.yaml.j2' %}
+{% include 'aero/obs/config/viirs_n21_aod.yaml.j2' %}
 {% endfilter %}