This proposal establishes a partnership between six international institutions on four continents to enable a platform for the development of inexpensive, user-configurable air pollution sensors. A particular focus of this application is building a network of solutions well suited for use in the developing world, where pollution levels, and corresponding public health risks, are highest. The team will construct a comprehensive framework for the development of low-cost air pollution sensing hardware and software, which can be used to address a global pandemic responsible for millions of premature deaths and altering our climate balance. The model follows a distributed effort approach, where WUN-affiliated investigators produce open-source and freely available software, coupled with hardware that is both inexpensive to obtain and easy to assemble. Providing these resources freely to our collaborators, as well as to anyone with internet access, will empower millions of people to build upon these developments providing a highly scalable and utilitarian instrument capable for answering a wide range...