This paper presents P-Sense (Pollution-Sense), a PS system for air pollution monitoring and control. The ultimate goal of this system is to allow government officials, international organizations, communities, and individuals access to the pollution data to address their particular problems and needs. P-Sense should provide large amounts of pollution data in time and space with different granularities. Government officials will have data to monitor and control the Air Quality Index (AQI) [1] of a city, state, or country; doctors will be able to correlate respiratory problems of their patients to the AQI they are exposed to during their daily activities, in the places they work and live; county officials, community developers, and realtors will have data to determine the best place where to build a new school or community and advertise properties according to the AQI where they are located.