The ability to quickly and reliably detect chemical toxicants in air is critically important for health risk assessment, for better understanding the role of gene-environment interactions in human diseases, and for health disparities research. Current detection of chemical toxicants relies on bulky and expensive spectroscopic and chromatographic techniques that require considerable maintenance and operator expertise, which are not practical for continuously monitoring various chemicals at multiple locations. Many portable devices have been proposed and developed, but they have different limitations ranging from low selectivity, insufficient sensitivity, limited scope and high costs. The present project brings together a joint effort involving chemical sensor researchers at Arizona State University (ASU), toxicologist at University of Arizona (UA), R&D scientists and engineers at Motorola and field testing experts at Arizona Division of Occupational Safety & Health (ADOSH) to build, validate and test a powerful wearable sensing system. The sensor technology is built upon a novel microfabricated tuning fork array sensor platform invented at ASU and wireless sensor technology developed at Motorola. The project will leverage on the expertise and resources gathered for an on-going collaborative R&D effort on wireless chemical sensors between the ASU and Motorola team. The goal is not only a wearable sensor system for quick, accurate and reliable detection of chemical toxicants, but also an affordable, easy-to-upgrade and user friendly product for population studies.