Exposure to air pollution can increase risk of serious mental health issues such as schizophrenia and depression, say researchers of a recent study conducted in London, UK.
The study published in the British Journal of Psychiatry is the most comprehensive of its kind on the subject involving 13,000 participants from London.
It only further bolsters what many scientists have said in the past regarding the worrisome impact of air pollution on mental health.
Here's what we know about the study, and why it matters.
About the Study
Here is a quick look at the key points of the study.
13 887 People over the age of 15 were selected for the study.
The researchers picked people had contacted the NHS (national health services) for psychotic and mood disorders between 2008 and 2012.
The air pollution levels vis-a vis specific pollutants —nitrogen dioxide (NO2), nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10)— in the residential areas of the participants were recorded.
Follow ups were conducted on the participants to record their admission to hospitals and the frequency of their visits to nurses, community doctors on account of their condition worsening.
The frequency of hospital stays and visits to community doctors were taken as a measure of severity or worsening of the condition.
Other variables that could alter the results such as age, sex, ethnicity, deprivation or population density were ruled out.
What the Study Found
The study found that the highest risk came from nitrogen dioxide (NO2) in the air.
Even a small exposure to nitrogen dioxide (NO2) led to a 32 percent increase in the risk of patients needing community mental health service (CMHS) events after just one year.
They also observed an 18 percent increase in the risk of being admitted to hospital.
Exposure to PM2.5 pollutants on the other hand lead to an 11 percent higher risk of hospitalisation and a 7 percent higher instance of patients needing CMHS.
An important finding of the study is that even small amounts of pollutants can significantly increase the risk of severe mental illness.
Why it Matters
In recent years, the impact of exposure to air pollution on various aspects of our health has been studied, and the link seems to get stronger each time.
The researchers of this particular study say that the point of it was not to establish a causal link of air pollution with higher risk of mental health but to establish that such a link of “biologically plausibility” exists.
Researchers of the study also pointed out that the findings apply to most cities in developed nations, and reiterate the need for meaningful interventions to reduce exposure to air pollution.
They hope that the study will prompt policymakers to factor in mental health while evaluating the cost of air pollution to the world economy.
Speaking of the kind of interventions that could help, Joanne Newbury, the lead author of the study was quoted by the Guardian as saying, "We know there are interventions that can be used, such as expanding low-emission zones. Mental health interventions at the individual level are actually quite difficult."
(Written with inputs from the Guardians.)
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