diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 2724dabaa..a42493859 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1081,6 +1081,7 @@ ecbuild_add_test( TARGET  test_${PROJECT_NAME}_aeronet_aaod
 
 ecbuild_add_test( TARGET  test_${PROJECT_NAME}_airnow
                   TYPE    SCRIPT
+                  ENVIRONMENT "PYTHONPATH=${IODACONV_PYTHONPATH}"
                   COMMAND bash
                   ARGS    ${CMAKE_BINARY_DIR}/bin/iodaconv_comp.sh
                           netcdf