Smoggy Brain?

Reading Time: 3 minutes

It’s hard to ignore; the increase in pollutants in the air is having a serious impact on human health, function and well-being. Outdoor air pollution has grown by 8% globally in the past 5 years, with billions of people around the world now exposed to dangerous air. It causes up to 7 million early deaths a year—more than malaria and human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) combined—and is now the greatest single killer in the world.

A recent paper in Nature – Human Behaviour written by researchers at MIT and the University of Beijing reviewed pollution data from 144 Chinese cities and monitored general happiness of urban dwellers by looking at the mood using 210 million messages from China’s largest microblogging platform, Sina Weibo. They found that it also makes people unhappy!

Many research papers out over the last few years have documented that air pollution has adverse impacts on health, cognitive performance, labour productivity and later-life educational outcomes. People engage in avoidance behaviour where they can by choosing to live in less-polluted cities and green buildings, buying self-protection products and reducing their time outdoors on highly polluted days.

The researchers suggest that when pollution levels are high that people are also more likely to engage in impulsive and risky behaviour that they may later regret. Such behaviour they suggest may be rooted in short term depression and anxiety driven in part by pollutants in the air.

They found a significantly negative correlation between pollution and happiness levels, with every increase in pollution value above a healthy level bringing happiness down by 0.04 points out of 100.

Some parts of London frequently record Air Quality Index (AQI) levels of 151, more than 100 points above healthy limits.

One of the core mechanisms involved.

Emerging data indicates that air pollution exposure adversely modulates the epigenetic marker, DNA methylation (DNAm), and that these changes might in turn influence inflammation, disease development, and exacerbates their risks.

Several traffic-related air pollution components, including particulate matter, black carbon, ozone, nitrogen oxides, and polyaromatic hydrocarbons, have been associated with changes in DNAm; typically lowering DNAm after exposure.

Effects of air pollution on DNAm have been observed across the human lifespan, but it is not yet clear whether early life developmental sensitivity or the accumulation of exposures have the most significant effects on health. But some studies are clearly showing relationships between air pollution and a risk factor for pregnancy loss and interference with organ development, especially impaired lung growth throughout childhood, and as a driver for the development of asthma

But could ingesting safe B vitamins as a mechanism for enhancing healthy methylation be a way to mitigate adverse effects of air borne pollution? One small (10) pilot mechanism cross over study showed that this approach may well confer individual benefits to people exposed to small particulate pollution fragments (PM2.5). They prescribed B-vitamin supplementation (2.5 mg/d folic acid, 50 mg/d vitamin B6, and 1 mg/d vitamin B12) and concurred that they may offer individual risk mitigation against oxidation and adverse methylation.

Early days in the recommendation for everyone to take B vitamins if living and working in a polluted area, but one with low risk, low cost and opportunity for short term mitigation

Other things to do to avoid the adverse effects of pollution include:

  1. Walking rather than driving
  2. Avoid main roads when walking or cycling
  3. Open your windows, let household pollutants out
  4. Reduce or stop using wood burners, or make sure you use seasoned wood
  5. Eat your vegetables


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