A British physicist from the University of Warwick has developed the first simple, universal method for calculating the motion of nanoparticles in air — regardless of their shape. This is a breakthrough: until now, existing models only worked with spherical particles, distorting real-world data. The new formula, published in the Journal of Fluid Mechanics (JFM), allows precise prediction of how viruses, soot, microplastics, and even inhaled medicines spread and move through the air.

Why Old Models Failed: The World Is Not Made of Spheres

Every day, we inhale billions of nanoparticles:

  • Soot from exhaust fumes
  • Microplastics from clothing and packaging
  • Viruses and bacteria
  • Pollen, volcanic ash, and synthetic nanomaterials

Particles smaller than 100 nm penetrate deep into the lungs, reach the bloodstream, and increase the risk of:

  • Heart attack (+20% with chronic exposure)
  • Stroke
  • Lung cancer
  • Asthma and allergies

The issue: 99% of these particles aren’t spherical. They’re discs, rods, flakes, or clusters, but classical equations — Stokes and Cunningham (1900–1920) — assumed perfect spheres. The result? Errors of up to 300% in calculating how fast particles settle or travel.

We’ve been modeling air as if only billiard balls were flying through it. In reality, it’s cubes, plates, and fibers, explains Professor Duncan Lockerby.

The New Formula: One Coefficient for Any Shape

Lockerby redefined the Cunningham slip correction (1910), which adjusts for how particles “slide” through gas molecules. He introduced a universal geometric factor that depends only on:

  • The aspect ratio (length/width)
  • The orientation in the airflow

The formula is expressed as:

Cc=1+λd⋅f(α,β)C_c = 1 + \frac{\lambda}{d} \cdot f(\alpha, \beta)Cc​=1+dλ​⋅f(α,β)

where f(α,β)f(\alpha, \beta)f(α,β) is the shape function — applicable to spheres, disks, cylinders, and clusters.

Results:

  • A single equation covers all shapes
  • Accuracy: ±5% (versus ±300% before)
  • Milliseconds to compute — suitable for real-time modeling

Tested on:

  • Spheres (classical validation)
  • Discs (microplastics)
  • Rods (viruses)
  • Flakes (soot)

Applications: From Smog Forecasts to Smart Inhalers

Field

What the new model enables

Air pollution

City-level smog prediction with street-level precision

Virus spread

COVID, flu, and pollen modeling — where particles land and how far they travel

Volcanic ash

Safer flight paths during eruptions

Medicine

Nanodrug delivery in lungs — targeting exact regions via inhalers

Industry

Smarter filters, nanomaterial design, 3D printing optimization

It’s like upgrading from a 19th-century map to GPS. We can finally see the real world of particles, says Lockerby.

What’s Next: From Lab to Life

  • 2026: Integration into ECMWF and NASA GEOS climate models
  • 2027: Smart air filters and masks with AI-based air quality prediction
  • Medicine: Adaptive inhalers that deliver drugs only to targeted lung zones

The University of Warwick is already patenting the technology, with open-source code set to appear on GitHub in 2026.

In Short

Physicist Duncan Lockerby has rewritten the Cunningham equation, creating a universal formula that precisely predicts the movement of nanoparticles of any shape through air. The discovery will revolutionize models of smog, viruses, and drug delivery, potentially saving millions of lives — a scientific breakthrough a century in the making.