Abstract: A health exposure sensor system includes a housing, a monitoring platform in the housing, and a power source. The monitoring platform includes at least one modular gas sensor, a circuit board having a microcontroller, and data ports for connecting the modular gas sensor to the circuit board. The housing includes manifolds to direct atmospheric air to the modular gas sensor. The modular gas sensor includes a gas detector and a gas sensor circuit board having a gas sensor microcontroller. The gas sensor microcontroller includes at least one on-chip universal asynchronous receiver-transmitter peripheral and at least one on-chip USB peripheral, where both peripherals include input/output functionality and are connected to a single data port interface for external communication. An associated method of operating the same includes selectively enabling individually either the UART peripheral or the USB peripheral via digital I/O configuration of the microcontroller.