This paper introduces a new real-time air pollution alert system using mobile devices. Through the location awareness capability of mobile devices, Android-and iOS-based apps are developed to inform the public residing in the vicinity of air pollution areas. The apps have shown to be working successfully sending push notifications as well as a regional map to convey the air pollution information to users. The apps and real-time air pollution alert system can also be extended for other natural environmental disasters such as hurricanes, flooding, and wildfires and man-made disasters such as chemical spills.