A Literature Review on Low-Cost Sensors with the Internet of Things Application in Indoor Air Quality Monitoring in Residential Buildings

Good indoor air quality (IAQ) is the basic requirement for well-being. In residential buildings that are private, autonomous and occupied for most of the time, keeping a good IAQ level is necessary, especially when there are children, elderly or other vulnerable populations. Within the development of gas sensors, its low-cost feature and Internet of Things application make it affordable, flexible and feasible even for ordinary occupants to do indoor air quality monitoring in their homes. This review searched papers (n=66) from SCOPUS and Web of Science about the low-cost sensors and Internet of Things applications in residential IAQ research, and After exclusion, a total of 23 studies are included with targeted research contents. This review aims to summarize several aspects of the active monitoring strategies in residential buildings, including (1) existing gas sensors, their target pollutants and working conditions; (2) sensor’s accuracy and calibration methods; (3) micro-controller unit selection and their monitoring applications; (4) data display and storage methods; (5) other possible application and limitations of low-cost sensors found in researches. These will help to build the tools for IAQ monitoring in residential buildings, for not only research purposes but also civilian applications.