PERSONALISED INDOOR AIR QUALITY SENSING & CONDITIONING: A REVIEW ON LOW-COST IAQ SENSORS

Abstract

In recent years, more attention has been given to indoor air quality (IAQ) as seen from the development of air quality sensors be it inexpensive to state-of-the-art ones. There are many low-cost IAQ sensors available on the market. However, there is insufficient literature exploring the performance of low-cost sensors. Most studies examine these sensors in highly controlled and sterile environments while few papers devote the exploration of low-cost sensors in field studies. In existing field studies, little has been done to examine the performance of IAQ sensors in various climates and sensor deployment. As such, the lack of holistic information on performance of low-cost IAQ sensors hinders the large-scale application of low-cost sensors.

This study explored the viability of deploying low-cost sensors on a large-scale by summarising the current field studies on low-cost IAQ sensors and their performance. In this dissertation, 101 papers on low-cost IAQ sensors were examined. They were filtered based on the relevant keywords in article repositories. A total of 23 relevant studies met the requirement of being a field study on low-cost IAQ sensor/sensors from the past ten years.

From the 23 papers, project location and duration, deployment of sensor, sensor type used, resolution and accuracy of sensors as well as a summary of the project conclusion were identified and extracted. From the following data, a summary table of the reviewed papers was generated followed by an evaluation of limitations and future directions. Results showed that most of the field studies conducted are concentrated in the select few (Köppen classified) temperate regions while the other climate regions are largely underrepresented in the study of low-cost IAQ sensors. It is also found that the absence of reference sensors for low-cost IAQ sensors undermines their potential as there is no standardisation for the calibration of low-cost sensors unlike their expensive counterparts. The possibility of standardising low-cost IAQ sensors is worth exploring in future studies as it will greatly increase the viability of the large-scale deployment of the sensors. This review paper will evaluate current low-cost sensor development efforts and standards to date, limitations, future directions of low-cost IAQ sensors and ways to improve IAQ through the personalisation of air.