Air Pollution Particles Shown to Attach to Red Blood Cells in New Studies

Recent scientific research has provided new evidence that ultrafine particles from traffic-related air pollution can enter the bloodstream and attach to red blood cells. These findings are based on experimental studies involving both volunteers and laboratory analysis.

In one experiment, BBC health correspondent James Gallagher stood next to a busy London road for ten minutes to inhale air containing traffic emissions. After this exposure, a blood sample taken from Gallagher revealed small black particles attached to his red blood cells when examined under a microscope.

Researchers observed that approximately one in every two to three thousand red blood cells carried a pollution particle following exposure to roadside air. Scaling this up to an adult’s typical blood volume, the scientists estimated that around 80 million red blood cells could be transporting these particles throughout the body.

A separate study conducted by Queen Mary University of London and Lancaster University involved 12 adult volunteers who were exposed to roadside air for one hour. This study found a two- to three-fold increase in the number of red blood cells carrying pollution particles, and also estimated about 80 million affected cells in five litres of blood.

What the numbers show

• One in 2,000–3,000 red blood cells carried a pollution particle after exposure
• About 80 million red blood cells in an adult may transport pollution particles
• 12 volunteers showed a two- to three-fold increase in affected cells after one hour

The studies found that the ultrafine particles measured around 10 to 15 nanometres in size, much smaller than the average red blood cell, which is about 7,000 nanometres wide. Analysis showed that these particles contained metals such as iron, copper, silicon, chromium, zinc, silver, and molybdenum, which are commonly associated with vehicle exhaust and brake or tyre wear.

Researchers at Queen Mary University of London reported that the level of pollution particles in the blood decreased after about two hours of breathing clean air. They also stated that wearing an FFP2 mask during exposure prevented the increase in pollution particles on red blood cells.

Prof Jonathan Grigg of Queen Mary University of London explained that ultrafine particles likely cross from the lungs into the bloodstream and may lodge in various organs. Other research has found black carbon deposits from air pollution in human placentas and organs, linking exposure to effects beyond the lungs.

The World Health Organization estimates that 99% of the global population is exposed to air pollution levels above recommended limits, contributing to millions of deaths each year. In the UK alone, poor air quality is estimated to cause around 30,000 deaths annually, and air pollution has been linked to health conditions such as asthma, dementia, heart attacks, strokes, lung cancer, and developmental problems in unborn babies.

* This article is based on publicly available information at the time of writing.