Effect of Relative Humidity and Air Temperature on the Results Obtained from Low-Cost Gas Sensors for Ambient Air Quality Measurements

• Published in: Sensors (Basel, Switzerland) Vol. 20; no. 18; p. 5175
• Main Authors: Samad, Abdul, Obando Nuñez, Daniel Ricardo, Solis Castillo, Grecia Carolina, Laquai, Bernd, Vogt, Ulrich
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 10.09.2020; MDPI
• Subjects: Air monitoring; air pollutants; Air pollution; Air quality; air quality monitoring; air quality sensors; Air temperature; Calibration; electrochemical low-cost sensors; Environmental monitoring; Gas sensors; Gases; Humidity; Influence; Laboratories; Low cost; low-cost sensors; Measuring instruments; Nitrogen dioxide; Pollutants; Relative humidity; Researchers; Sensors; System effectiveness
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s20185175

Using low-cost gas sensors for air quality monitoring promises cost effective and convenient measurement systems. Nevertheless, the results obtained have a questionable quality due to different factors that can affect sensor performance. The most discussed ones are relative humidity and air temperature. This investigation aimed to assess the behavior of B4-series low-cost gas sensors from Alphasense for measuring CO, NO, NO2, and O3 for different levels of relative humidity and temperature. These low-cost gas sensors were tested for six relative humidity levels from 10% to 85% with increasing steps of 15% and four temperature levels of 10 °C, 25 °C, 35 °C, and 45 °C against reference instruments in the laboratory. The effect of these parameters on low-cost gas sensors was quantified in laboratory from which a correction algorithm was calculated, which was then applied to the field data. The applied algorithm improved the data quality of the low-cost gas sensors in most of the cases. Additionally, a low-cost dryer was assessed to reduce the influence of these factors on the low-cost gas sensors, which also proved to be suitable to enhance the data quality.