Does Air Pollution Damage Brain Health?

Air pollution could be detrimental to brain functioning in older men, according to the results of a new collaborative study from the USA and China. Perhaps most concerningly of all, the brain can be adversely affected even when it is only exposed to higher levels of contamination for a short period of time.

The paper is simply the latest in a growing body of research which suggests that poor air quality could be having a disastrous effect on the body’s physical, mental and cognitive health. The fact that adverse performance was observed in participants who had been exposed to a lower concentration of pollutant than that deemed safe by the World Health Organisation (WHO) will only underline the seriousness of the issue to concerned campaigners.

The stats don’t lie

The study focused on particulate matter 2.5 (PM2.5), which are tiny particles of pollution less than 2.5 micrometres in diameter. Our awareness of these microscopic contaminants has advanced in recent years with sophisticated new methods of measuring its concentrations in ambient air, which has alerted us to the myriad health dangers that it carries.

As part of their work, the researchers from China and the US assessed cognitive test scores of almost 1,000 men living in Massachusetts. The average age of the participants was 69 and their scores were cross-referenced against concentrations of PM2.5 in their area up to four weeks before the test was taken. The findings revealed that the men consistently performed more poorly at number recall and verbal fluency, among other tasks, when they had been exposed to higher levels of the contaminant in the preceding days and weeks.

That discrepancy was even noticeable when the concentrations of PM2.5 stayed below 10 micrograms per cubic metre, which is the threshold recommended by WHO as “safe”. Even more worryingly, cities such as London regularly breach that threshold, while the UK government has set itself a higher threshold of 25mg/m, claiming that anything below 35mg/mshould be regarded as low.

Taking action

Although this particular study only examined the impact upon the brains of men aged 69 or over, it has added to a growing body of evidence which suggests PM2.5 exposure could be responsible for dementia, limited intellectual capacity and a raft of other cognitive ailments. PM2.5 is most commonly found in compromised air quality near construction sites, demolitions or other industrial facilities or in big cities with heavy traffic.

This has prompted environmentalists and concerned campaigners to urge the Conservative government to do more to clean up the country’s airways. The introduction of ultra-low emissions zones (ULEZs) and a targeted transition to electric vehicles (EVs) are some of the initiatives that the government have instigated, but critics say they do not go far enough.

On a personal level, there are things that individuals can do to protect themselves. Interestingly, the study found that subjects who were taking aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) suffered less adverse reactions, but the side-effects which many people experience from these drugs mean that doctors do not advocate taking them unprescribed. Instead, following a balanced diet and getting plenty of exercise can help to reinforce the immune system and protect against the most deleterious effects of PM2.5 exposure.