PERFORMANCE EVALUATION OF A LOW-COST SENSOR FOR CONTINUOUS METHANE MONITORING

Abstract

Methane is a significant contributor to climate change. Methane budgets calculated by different methods can vary up to 50%. Understanding methane sources and sinks is critical to managing emissions. Temporal variability accounts for some of the disagreements in budgets. Current measurement methods are costly and inadequate for long term, continuous monitoring. Low-cost methane sensors are needed for accurate budgets, but these sensors are sensitive to changes in temperature and humidity. A metal oxide semiconductor sensor was evaluated, and an environmentally controlled enclosure was developed to assess the impact of controlling temperature and humidity on the sensor’s accuracy. The results demonstrated humidity had the strongest influence on sensor response. In a laboratory environment, the sensor measured methane concentrations with a root mean square error of 1.3 ppm. The enclosure stabilized temperature within 2.5°C and relative humidity within 4%. Use of the enclosure improved sensor accuracy, but not enough to estimate emissions.