Equity, accessibility, and public health implications of digital platforms delivering real-time air quality information: A technology review.

According to the World Health Organization, air pollution is the largest environmental risk to global health, with 99% of the world's population living in areas exceeding recommended guidelines. Providing real-time air quality information through mobile or web-based applications, alongside behavioural guidance, represents a key strategy for reducing individual exposure and improving population health. Such information is delivered at varying geographic and temporal scales and has become increasingly widespread and decentralised. However, there is limited understanding of the quality, characteristics, and potential health impacts of digitally available air quality information and messaging. This study addresses this gap through a systematic technology review of publicly available digital platforms ("channels") that share real-time local air pollution data. Using the UK as a case study, computational methods were applied to examine how data underpinning existing channels (websites, mobile applications, sensors, etc.) are generated and by whom. Systematic searches of Google, the Google Play Store (Android), and Apple App Store (iOS) were conducted using SerpAPI and predefined search terms. In total, 146 channels met inclusion criteria and were analysed. Channel metadata were used to identify trends in channel types, evolution over time, and emerging patterns across the digital information landscape. The review also compares differences in available information across channels but is limited to those accessible in the UK and excludes real-time social media data due to cost and access constraints. Finally, the study considers demographic and social factors influencing access to air quality information and its exposure-reducing benefits. These findings contribute to understanding the production and use of digital air quality information with global public health relevance.