Mobile Technologies, Applications and Software Design Elf Body Environment Wellness App by Tiange Wang and I-Yang Huang Elf is an innovative mobile app that fosters the connection between environment health and body health by offering personalized suggestions about indoor environmental improvements and behavioral change. With realtime environmental and health data, Elf coaches and nudges the user about actions they could take to their indoor environment to improve how they feels and performs. The design incorporates intuitive and interactive data visualization with beautiful, soft grainy color gradients and uses conversational UI to align the character of the app to a house elf for stronger emotional appeal.