Smartphones have become more and more popular in the past few years. Motivated by the fact that location plays an extremely important role in mobile applications, this paper develops an efficient local message dissemination system PASA based on a new communication model called passive broadcast. It is based on the method of overloading device names described in MDSRoB  and Bluejacking . In this new model, each node does not maintain connection state and data delivery is initialized by a receiver via a 'scan' operation. The representative carriers of passive broadcast include Bluetooth and WiFi-Direct, both of which define a mandatary 'peer discovery' scan function. Passive broadcast features negligible cost for establishing and maintaining direct links and is extremely suitable for short message dissemination in the proximity. In this paper, we present PASA with complete protocols and in-depth analysis for optimization. We have prototyped our solution on commercial phones and evaluated it with comprehensive experiments and simulation.