ngrx4-effects-multiple-action-dispatch

You can use the from creator and the mergeMap operator to merge an observable into the effect's Action stream.

Using your example:

@Effect() addPeopleStart$ = this.actions$
  .ofType( PersonActionTypes.ADD_PERSON_LIST_START )
  .switchMap(
    ( payload ) => {
      return this.personService.getPeople();
    }
  )
  .mergeMap(
    ( result: string[] ) => {
      return Observable.from([ new AddPersonList( result ), new AddPersonListComplete() ]);
    }
  )