impact of air pollution

Hardly a week goes by, it seems, without some new research on the impact of air pollution on health...this time, it’s about brain damage and the risks of exposure to air pollution to people who have had a lung transplant.

  • Writing in Environmental Health Perspectives, researchers at the University of Southern California have found that Particulate Matter (PMs) causes brain damage in mice which is not unlike that found in memory loss and Alzheimer’s disease. They collected air samples containing PMs from a local urban freeway and created a suspension with it, to which the mice were exposed over a ten week period. The researchers also did some experiments where they applied the simulated air pollution to rat brain cells. They discovered a distinct pattern for the impact of air pollution and brain damage, one that involves a brain chemical called glutamate.That’s concerning, because glutamate is involved in learning and memory. Faulty glutamate pathways have been implicated in dementia. Of course, research on mice is a long way from doing experiments on humans living in real situations (but often findings in mice are replicated in the human situation). There could be serious implications here for children attending schools near roads where traffic pollution is heavy.
  • Patients who have had a lung transplant tread a fine line for the rest of their lives. Their immune system will naturally tend to reject their new live-saving organ. This means they must take powerful drugs to suppress their immunity - but this leaves them at increased risk of infection and cancer. Too little suppression means possible organ rejection, too much leaves the body undefended. There is a condition called Bronchiolitis Obliterans Syndrome (BOS) which signifies rejection in lung transplant patients. Researchers in Belgium did a study on the impact of traffic air pollution on the risk of BOS in 288 patients who had had a lung transplant. During five years of follow up, 41% of patients developed BOS and 21% died. Patients living close to a major road were twice as likely to develop BOS and twice as likely to die as those living further away. It would be interesting to know if air pollution is linked to similar risks in people with other types of organ transplant, such as kidney and heart. The impact of indoor air pollution on transplant patients is also worthy of investigation, since people spend so much of their day indoors.

The above study focuses upon the impact of air pollution on the risk of rejection. But what about the other side of the coin - the risk of infection from a suppressed immune system? HEPA air purifiers are used in leading hospitals to reduce the spread of viruses and bacteria. Viruses are very small - some less than 0.03 microns in diameter. Best removal of viruses comes from mechanical HEPA filtration, such as an IQAir HealthPro 250. It is a set up which, if properly configured for airflow, will go a long way to protecting transplant patients from infection.


1. Morgan T et al Glutamatergic neurons in rodent models respond to nanoscale particulate urban air pollutants in vivo and in vitro Environmental Health Perspectives April 7 2011

2. Nawrot T et al The impact of traffic air pollution on bronchiolitis obliterans syndrome and mortality after lung transplantation Thorax Online First 23rd March 2011