The CityAirSim VR application presents a promising platform for urban air quality visualisation, but its UI/UX design can significantly impact user experience and usability. This usability evaluation study employed a mixed-methods approach, utilising usability tests, semi-structured interviews, and the User Experience Questionnaire (UEQ) to evaluate the application. As part of the evaluation, a new 3D menu with a direct manipulation interaction method was developed and compared to the existing 2D menuwith point-and-click interaction as part of the evaluation. Thirteen participants participated in the evaluation, highlighting effective aspects suchas ease of use, visibility, interactiveness, and feedback for both menus. However, issuessuch as visibility and visual design improvements were identified for both menus. Suggestions include improving menu state indicators and providing tutorials for better learnability. As for the preference between the menus, a majority of participants (n=11,85%) preferred the 3D menu. The UEQ and interview results indicate that the hedonic factors significantly influenced the preference between the 3D and 2D menus