Abstract
Over the past decade, technological advancements and the growing demand for higher spatial resolution in air quality measurements have driven the widespread deployment of low-cost electrochemical gas sensors. These sensors are inexpensive, compact, easy to deploy, and have potential to detect variability in ambient air. While short-term sensor performance and calibration assessments have been well-documented, research on sensor reliability in long-term deployments remains limited. The Berkeley Environmental Air Quality and CO(2) Network (BEACO(2)N) is a dense, long-term sensor network measuring O(3), NO, NO(2), and CO using electrochemical gas sensors, in addition to CO(2) and PM(2.5) with other sensors. Here, we evaluate the performance of the Alphasense NO2-B43F, Ox-B431, NO-B4, and CO-B4 sensors over the course of 3 years in the San Francisco Bay Area. We find consistent performance in the calibrated data over the 3 years. These findings highlight the reliability of long-term sensor use with appropriate calibration techniques and suggest the sensors remain suitable for extended deployments without requiring replacement.