Key Themes, Trends, and Drivers of Mobile Ambient Air Quality Monitoring: A Systematic Review and Meta-Analysis

Mobile ambient air quality monitoring is rapidlychanging the current paradigm of air quality monitoring andgrowing as an important tool to address air quality and climatedata gaps across the globe. This review seeks to provide asystematic understanding of the current landscape of advances andapplications in this field. We observe a rapidly growing number ofair quality studies employing mobile monitoring, with low-costsensor usage drastically increasing in recent years. A prominentresearch gap was revealed, highlighting the double burden of severeair pollution and poor air quality monitoring in low- and middle-income regions. Experiment-design-wise, the advances in low-costmonitoring technology show great potential in bridging this gapwhile bringing unique opportunities for real-time personalexposure, large-scale deployment, and diversified monitoring strategies. The median value of unique observations at the samelocation in spatial regression studies is ten, which can be used as a rule-of-thumb for future experiment design. Data-analysis-wise,even though data mining techniques have been extensively employed in air quality analysis and modeling, future research can benefitfrom exploring air quality information from nontabular data, such as images and natural language