Destroy broadcast event listener

Hi guys, well the title sums it app… How can I destroy my broadcast event after it runs because it fires everytime I move to another state… Here is my event listener…

.run(function ($ionicPlatform, $rootScope, $cordovaSplashscreen, $location, $timeout, $state, $ionicPopup, Authorization) {
    var removeListener = $rootScope.$on('$stateChangeStart', function (event, toState, toParams, fromState, fromParams) {

		if (window.localStorage.getItem("username") === null && window.localStorage.getItem("password") === null) {
        else {