This paper describes a portable sensor system design for environmental research. The designed system has been deployed in many environments and has been EMI/EMC approved for operation in commercial aircraft cabins. The sensor suite includes particulate matter, CO, CO2, temperature, humidity, pressure, light intensity, and sound sensors. Multiple sensor systems can be deployed at once to form a wireless sensor network. Each sensor node is powered either with six AA batteries or via a transformer and standard outlet. The data collected by a node can be stored locally on the device and/or sent through the integrated ZigBee mesh network to a central coordinator node. As of this writing, single nodes have been carried by passengers to monitor the normal airliner cabin flight conditions, and networks have been used to monitor indoor and outdoor air quality conditions.