Small-scale optical particle counters for actionable air quality data in resource-limited settings

Atmospheric pollution has become a global concern and is the second leading factor of premature deaths. Around 8 million deaths globally, and 1.1 million in Africa are attributed to poor air quality. In the Global south, resource-limited communities experience high pollution levels but lack data to inform policies. In recent years, interest grew in Africa among researchers and professionals to generate data from small and low-cost optical particle counters (OPCs). They are cheap, easy to deploy and maintain, but fail to provide accurate data. Therefore, they require collocation with high grade monitors and calibration, which can be a time-consuming process. Handheld OPCs have the capability to provide high quality data, and do not need calibration. This study introduces how portable air quality monitors can efficiently track traffic-generated particles in urban centers. Fine particles concentration varies across cites but remains high: 32-79 µg.m^-3 in Thiès (Senegal), 82-113 in Douala (Cameroon), 100-500 in Cotonou (Benin), 33-328 in Addis Ababa (Ethiopia). Options for small OPCs and constraints for wide deployment are presented. Solutions and strategies to sustainable provision of air quality data are also highlighted.