New Study Reveals How Air Pollution Particles Travel Through the Body on Red Blood Cells

Recent research has provided the first direct evidence that tiny particles from air pollution can attach to red blood cells, allowing them to circulate freely throughout the human body. These microscopic particles, primarily generated by vehicle exhaust, brake and tire wear, are small enough to enter the lungs and have been previously linked to adverse effects on the brain and heart. However, the pathways through which they infiltrate various organs remained unclear until now.

The study, published in ERJ Open Research, involved 12 healthy adult volunteers who spent time in a controlled experiment near a busy London road. The participants first stayed in an office environment for four hours, then spent an hour within 10 meters of a heavily trafficked street. During these periods, they carried devices that measured the air pollution levels around them. Blood samples collected at different intervals—before exposure, immediately after roadside exposure, and after returning to the office—revealed an increase in pollution particles attached to the red blood cells post roadside exposure.

The levels of particulates on red blood cells nearly quintupled when near traffic. On average, two to three times more pollution particles adhered to each person's red blood cells after just one hour beside a busy road. While only a small fraction of red blood cells carried particles, calculations suggest that around 80 million cells in just 5 liters of blood could be transporting pollution throughout the body after roadside exposure.

Interestingly, the use of an FFP2 mask during the roadside period prevented the increase in attached particles, indicating the effectiveness of protective face coverings in reducing inhalation of these harmful particles.

Further laboratory experiments confirmed that human and mouse red blood cells readily pick up diesel exhaust particles. Analysis of the particles identified common pollutants like iron, copper, silicon, chromium, zinc, silver, and molybdenum—originating from vehicle emissions, brake wear, and tire abrasion. All particles measured 2.5 micrometers or smaller, aligning with the PM2.5 pollution standard.

Professor Jonathan Grigg emphasized that red blood cells are responsible for oxygen transport, and their hijacking by pollutants means these particles could reach and affect many organs. This research lays a foundation for developing simple methods to measure pollution ingress into the body and highlights the importance of masks and policies aimed at reducing air pollution exposure, especially for vulnerable populations.

Epidemiologist Professor Ane Johannessen highlighted the significance of these findings, urging for stricter air quality regulations to minimize health risks associated with pollution, particularly for those with existing health conditions or in high-exposure environments.

This study underscores the need for protective measures and better regulation to safeguard health from airborne pollutants, illustrating how tiny pollution particles can more deeply infiltrate the body than previously understood.