Particulate pollution 'damages cognitive function'

Particulate pollution create by road traffic could lead to cognitive decline later in life. A new US study has suggested that particles emitted by exhausts and other forms of air pollution could increase the decline of brain function in older adults, reports Reuters.

The study, performed by researchers at the Center for Biodemography and Population Health and the Andrus Gerontology Center at the University of Southern California, looked at the link between cognitive function and air pollution in adults. Jennifer Ailshire, co-writer of the report, said that although a lot of focus has been given to how air pollution can affect the health and development of the brain, little research has been done to see what this means for the ageing brain.

Ms Ailshire - along with Philippa Clarke from the Institute for social Research at the University of Michigan - suggested that making efforts to improve air quality could help to reduce the number of people suffering from age-related cognitive decline. The researchers point to previous studies that show there is a higher rate of decline in more polluted areas, with the link not being explained by social factors.

The team collected information from an ongoing study that began in 1986. The analysis was based on 780 study participants aged 55 during the 2001/2002 survey. Each participant's cognitive function was measured by memory and math tests, which scored them based on the number of mistakes made.

Each participant's air pollution exposure was also calculated. This was done using the particulate pollution levels measured by the US Environmental Protection Agency's (EPA's) Air Quality System. It was found that the average exposure to PM2.5 - particulate matter measuring under 2.5 micrometres - concentrations was around 13.8 micrograms per cubic metre. This is above the EPA's guideline of 12 micrograms per cubic metre. 

After the results had been adjusted for social factors - such as employment, marital status and education - the differences in cognitive rates stayed the same. This suggests that particulate pollution could be as damaging to brain function as it is to the heart and lungs.