Air quality affects the health and well-being of each of us, especially those with chronic respiratory diseases. Acute exposure to fatal levels of hazard materials causes millions of accidents every year, and unnoticed long- term exposure to lower levels of chemicals affect far more people. Various technologies have been developed to monitor air quality, but none of them is capable of detecting multiple chemicals in a user-friendly and affordable manner. This project will focus on creating an integrated multi-analyte device for monitoring personal environmental exposure. The target analytes include ozone, nitrogen dioxide, sulfur dioxide, and formaldehyde, which are identified as major indoor and outdoor pollutants by Environmental Protection Agency, World Health Organization, and Occupational Safety and Health Administration. Such a device, if successfully developed and validated, will have a profound impact on the protection of workers, reduction of environmental disease triggers, and prevention of respiratory diseases. The project will bring together strengthens in chemical sensor development and commercialization from TF Health Co., and Center for Bioelectronics and Biosensors, the Biodesign Institute, at Arizona State University. In phase I, the team will 1) develop sensing elements based on hierarchical sensing materials, 2) optimize the sensing elements to achieve high humidity and temperature tolerance, and 3) develop an adaptive sampling algorithm to achieve continuous monitoring capability. In phase II, we will 1) integrate the sensing elements together with digital circuits, optoelectronic detection chamber, sampling system, and software, 2) perform rigorous analytical validation with standard analytical equipment, and 3) perform pilot field tests under both indoor and outdoor settings.