A method for providing air quality information is disclosed. The method includes steps of collecting single-point air quality data from a plurality of mobile devices in a predetermined period of time, wherein the single-point air quality data is sensed by an actuating and sensing module of the mobile device and transmitted to a cloud data processing device through communication transmission. The single-point air quality data is combined with geographic information and processed to generate a real-time air quality map by the cloud data processing device. After the cloud data processing device receives a current location from a client device through communication transmission, information including a motion direction, a designated route, air quality information related to the current location, abnormal-air-quality notification or an evacuated route is transmitted to the client device.