Shellcheck approved way to pass 2 arguments in one variable, to a command in a bash script

In a bash script, I call another programme, but I want to configure that programme with a command line option. The following works:

AREA_ARG=""
if __SOME_SETTING__ ; then
  AREA_ARG=" --area us,ca "
fi

process_data -i /some/path $AREA_ARG

i.e. bash either executes process_data -i /some/path, or process_data -i /some/path --area us,ca . However [shellcheck](https://www.shellcheck.net/) complains!

$ shellcheck test.sh 

In test.sh line 7:
process_data -i /some/path $AREA_ARG
                           ^-------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
process_data -i /some/path "$AREA_ARG"

For more information:
  https://www.shellcheck.net/wiki/SC2086  -- Double quote to prevent globbing ...

I understand the principle, but I _want_/_need_ the variable to split on the space so that process_data gets 2 arguments. What's the Proper Way™ to do this in bash?