A Calibrated Low-Cost PM2.5 Sensor Network Across Burkina Faso's Three Largest Cities

Most cities in the Sahel, including Burkina Faso's, have no reference-grade air-quality monitoring, leaving residents and city governments without data to act on pollution levels.

Burkinabé university teams and Italy's CNR-IBE set out to test whether a network of low-cost, locally calibrated sensors could reliably fill this monitoring gap.

Nineteen Clarity optical PM2.5 sensors were installed at 13 sites in Ouagadougou and three each in Bobo-Dioulasso and Koudougou, with readings corrected using a Gaussian Mixture Regression model trained on a two-month co-location against a TEOM reference monitor; the network ran continuously from November 2021 to November 2022, alongside companion deployments in Niger and Guinea to compare performance across contexts.

Corrected mean daily PM2.5 concentrations across Burkina Faso sites ranged from 17 to 68 µg/m3, averaging 46.7 µg/m3 overall and 48.5 µg/m3 in Ouagadougou — roughly nine to ten times the WHO daily guideline, with estimated annual levels 11-14 times the WHO annual guideline.

A companion 'lessons learned' paper is candid that the network required ongoing effort to manage dust fouling, power interruptions and calibration drift, framing the approach as practical guidance for future low-cost deployments rather than a finished, maintenance-free system.