iMAP: Indirect measurement of air pollution with cellphones

In this paper, we introduce the cellphone-based indirect sensing problem. While participatory sensing aims at monitoring of a phenomenon by deploying a dense set of sensors carried by individuals, our indirect sensing problem aims at inferring the manifestations of a sparsely monitored phenomenon on the individuals. The main advantage of the indirect sensing method is that, by making use of existing exposure modeling and estimation methods, it provides a more feasible alternative to direct sensing. Collection of time-location logs using the cellphones plays a major role in our indirect sensing method, while direct sensing at the cellphones is unneeded. We focus on the air pollutant exposure estimation problem as an application of the indirect sensing technique and propose a Web-based framework, iMAP, for addressing this problem. We also discuss the information quality (IQ) requirements of indirect sensing in the iMAP framework.