A computationally efficient monodisperse particle dynamics–computational fluid dynamics simulation is developed to predict soot particle growth in flames without use of reaction kinetic models. The proposed model is in good agreement with soot volume fraction and mobility size measurements, demonstrating a level of accuracy comparable to that of sectional models. This model can be readily used for design applications of engines and industrial burners.

Clouds in cold regions affect climate and precipitation, but their behavior depends on rare airborne particles that help ice form. We measured these particles over several months in a Finnish forest and compared them with many environmental observations. We found that ice formation in winter was largely unpredictable, while in spring and summer it was more strongly linked to particle amount and composition. This shows that local conditions are needed to better represent clouds in climate models.