Abstract
Low-cost sensors (LCS) for indoor and ambient air quality monitoring have gained significant attention in recent decades due to their affordability, availability, and potential for broad usage in various environments. LCS are available in diverse types, each with its own specifications. These sensors present a cost-effective solution for air quality monitoring, enabling individuals, communities, agencies, and organizations to obtain real-time concentrations of gaseous and particulate matter (PM). Numerous studies have examined the pollutants that can be monitored by LCS, including different size fractions of PM such as PM2.5 and PM10 (with an aerodynamic diameter equal to or less than 2.5 and 10μm, respectively), carbon monoxide (CO), carbon dioxide (CO2), ozone (O3), nitrogen dioxide (NO2), and total volatile organic compounds (TVOC). Monitoring pollution levels provides valuable insights into potential sources and aids in implementing appropriate mitigation strategies. LCS-based indoor air quality (IAQ) monitoring allows occupants of residences, schools, and workplaces to assess the IAQ within their premises. Similarly, LCS-based ambient air quality monitoring complements the existing network of monitoring stations and improves spatial coverage. With advancements in sensing technology, LCS units can be utilized in stationary, mobile, and wearable applications, either as stand-alone devices or as part of wirelessly-connected networks to fulfill their designated roles. Today, LCS-based units are capable of remotely collecting, storing, transmitting, processing, analyzing, and visualizing data as required. However, challenges associated with LCS, such as data accuracy, calibration, validation, and quality assurance, persist. Efforts are ongoing to enhance the reliability and usability of this technology in all aspects. LCS units serve as valuable tools for monitoring air pollution, raising awareness, promoting community-driven initiatives, and driving policy changes in air quality management and public health. In this chapter, we elaborate on the aforementioned elements to equip readers with comprehensive knowledge of LCS.