Secondary organic aerosols (SOA) are a major source of uncertainty in climate models. This study investigates the contribution of agricultural recycling of organic waste products, specifically sewage sludge, to SOA formation. Laboratory experiments show that skatole, a compound emitted from sewage sludge, reacts with ozone and SO2, leading to intensive new particle formation (NPF) with nucleation rates up to 1.1 × 10⁶ cm⁻³ s⁻¹. A proposed ozonolysis mechanism is discussed, and an estimate suggests that this agricultural activity contributes approximately one ton of particles annually in France, potentially impacting local air quality during the spreading period.

R. Ciuraru, J. Kammer, C. Decuq, M. Vojkovic, K. Haider, Y. Carpentier, F. Lafouge, C. Berger, M. Bourdat-Deschamps, I. K. Ortega, F. Levavasseur, S. Houot, B. Loubet, D. Petitprez, C. Focsa