Living amid high levels of air pollution increases one’s risk of developing depression and commiting suicide, says new research from University College London. These findings, say researchers, should strengthen calls to reduce air pollution, and address what the World Health Organization considers a “silent public health emergency”.
Leader of the investigation, Isobel Braithwaite said, “We know that the finest particulates from dirty air can reach the brain via both the bloodstream and the nose, and that air pollution has been implicated in increased (brain) inflammation, damage to nerve cells and to changes in stress hormone production, which have been linked to poor mental health.”
To understand this knowledge existed in concrete reality, Braithwaite and her team analyzed data from 16 countries including China, the US and Germany over a 40-year period, specifically honing in on the link between particle pollution, particles smaller than 2.5 micrometres (PM2.5), and mental health outcomes.
In their results, they found a strong statistical link between air pollution and depression and suicide. In total, they noticed that people exposed to an increase of 10 micrograms per cubic metre in levels of PM2.5 for a year or more were 10% more likely than others exposed to cleaner air to get depressed. They also found that as a short-term effect, an increase of 10 micrograms per cubic meter of PM10 (particles measuring up to 10 micrometers) increased one’s chances of committing suicide by 2%. This is jarring information when we consider that some cities, such as Delhi in India, regularly have levels of PM2.5 of 150+ micrograms per cubic meter regularly, alongside PM10 levels exceeding 80 micrograms per cubic meter.
However, despite the confidence many have in the correlation between air quality, depression and suicide, some remain skeptical. John Ioannidis from Stanford University for example, is not convinced by the findings. Given that most of the studies to date looking at a correlation between air quality and mental health have high degrees of uncertainty, he said, “Putting them together in a meta-analysis reduces this uncertainty somewhat, but may give some false reassurance that we know more than we really do. “
Although he recognizes the ill effects of air pollution on general health, he added, “I worry that by trying to expand the range of diseases that are putatively associated with air pollution, we forget that air pollution is already proven to be bad in major ways, including death risk. Instead of acting on it, we may end up asking for more research, wasting valuable time. “