Scientists have solved a long-standing problem in fluid dynamics by developing a new way to predict how microscopic particles move through the air. The breakthrough addresses a limitation in a century-old equation that has been widely used to estimate the drag and resistance acting on tiny particles suspended in gases. The research could significantly improve models used to understand air pollution, climate behavior, and the spread of airborne diseases, tells this article from Popular Mechanics.
The problem dates back to 1910, when British scientist Ebenezer Cunningham introduced what became known as the Cunningham correction factor. This mathematical adjustment allowed researchers to calculate the drag experienced by extremely small particles moving through air. Although the formula proved valuable for aerosol science, it contained a major simplifying assumption: it treated all particles as perfectly spherical. In reality, many airborne particles, including dust, smoke, viruses, and microplastics, have irregular shapes. This mismatch limited the accuracy of predictions about how such particles drift and disperse in the atmosphere.
To address this issue, mathematician Duncan Lockerby of the University of Warwick revisited Cunningham’s model and developed a more general mathematical approach. His solution introduces what he calls a “correction tensor,” a mathematical framework that can account for particles of many different shapes rather than just spheres. By incorporating more realistic geometry into the calculations, the method enables researchers to estimate the drag and motion of irregular particles more accurately.
The new framework could enhance predictive models used in several fields. Atmospheric scientists rely on particle-movement models to track pollution, wildfire smoke, and other aerosols that affect climate and human health. Epidemiologists studying airborne disease transmission may also benefit from improved predictions of how microscopic particles travel through the air.
Lockerby plans to test the new mathematical model using an aerosol-generation system capable of creating controlled clouds of particles. If validated experimentally, the approach could refine atmospheric simulations worldwide and deepen scientists’ understanding of the invisible particles that constantly circulate in the air humans breathe.