Siriel Saladin

1. Introduction Click to copy section linkSection link copied! The World Health Organization attributed 6.7 million deaths in 2019 to air pollution. (1) Road traffic in 2021 is reported to cause 8% of the European Union’s emissions of airborne particles with aerodynamic diameters below 2.5 μm (PM2.5) as well as 10 μm (PM10).

- Perspectives - by Siriel Saladin on March 26, 2025 This article is part of a series, where we explore the hidden complexities of PM2.5—tiny airborne particles that impact air quality and health. We will uncover the ambiguities behind its measurement, the challenges in assessing health risks, and the surprising insights that emerge. Each article will tackle a different aspect of PM2.5, shedding light on its hidden dilemmas and unanswered questions.

Introduction In September 2024, we published an article about PM2.5 and how the EPA correction algorithm improves the accuracy of AirGradient’s monitors. We observed that our sensors, the PMS5003 from Plantower, systematically overestimate PM2.5 when concentrations are above 10 to 20 µg/m3. The algorithm from the EPA ( equation 4) does a great job of bringing down the high readings. Meanwhile, we have implemented the algorithm for our outdoor and indoor monitors, as explained .