There is a growing number of applications that take advantage of the smartphone’s image sensors, display, computing and data storage capabilities, and connection to clouds. Incorporation of bio/chemical detection into smartphone platforms is a potentially powerful development, as the previously expensive laboratory-based instruments may be available to anyone. Our objective is to develop a smartphone based system that offer a simple and rapid route to spectroscopic sensing of chemical species absorbed. For example, acid gas and formaldehyde gas detection.  The sensor will be integrated on an iPhone so that it can be portable and user friendly. During the sampling period the sensors will detect the gases and the functions of flashlight and taking photos in iPhone will be used to acquire information from the sensors. Then the concentration of the gases will be analyzed by the App we create in the iPhone and it will also provide useful suggestions such as how to protect yourself or whether leave that place or not. Also user can share their result online or see the results from other people.