New Research Links Air Pollution to an Increased Risk of Depression and Suicide

Earlier this week, a joint statement released by the Climate and Health Alliance (CAHA) declared that Sydney's poor air quality, in the wake of ongoing bushfires across the state, constituted a "public health emergency." Within the past month, the city’s air pollution has reached levels up to 10 times worse than some of the most polluted cities in the world, while New South Wales at large is currently experiencing its longest and most widespread period of poor air quality on record.

The CAHA statement linked such extreme levels of hazardous pollution to "premature births, low birth weight babies, impaired lung development in children, asthma, heart disease, stroke, chronic obstructive pulmonary disease, and lung cancer." But a new study published in Environmental Health Perspectives this week found that high levels of air pollution could also be causing “substantial harm” to our mental health.

A team of researchers from University College London (UCL) and King’s College London looked at data from 16 countries, assessing their levels of air pollution according to the amount of fine particulate matter — that is, tiny particles of dust and soot — in micrograms per cubic meter. They then examined evidence of links between air pollution and five mental health outcomes: depression, anxiety, bipolar, psychosis, and suicide.

What they found was that an increase of just 10 micrograms of fine particulate matter per cubic metre over an extended period of time could increase a person’s risk of depression by as much as 10 percent. For reference, the amount of fine particulate matter in Delhi, India's air has reached levels of 114 micrograms per cubic metre — a number that could bear worrying implications for the millions of people who live there. At the time of writing, Sydney’s levels had reached 115 micrograms.

Long-term exposure to fine particulate matter was linked to depression and anxiety, though, researchers also found that short-term exposure to coarse particulate matter — such as those found in dust and smoke — appears to influence the risk of suicide. According to their research, a person who is exposed to coarse particulate matter over a three-day period could see a 2 percent increase in their suicide risk for every 10 micrograms of that matter per square metre.

It’s worth stressing that the authors of this study aren’t necessarily suggesting air pollution directly causes mental health problems, but merely identifying that there seems to be some sort of link between the two.

"Our findings correspond with other studies that have come out this year, with further evidence in young people and in other mental health conditions,” said senior author Dr Joseph Hayes in a statement. “While we cannot yet say that this relationship is causal, the evidence is highly suggestive that air pollution itself increases the risk of adverse mental health outcomes."

Meanwhile, the fires continue to rage throughout NSW and across Australia with no end to the catastrophe in the foreseeable future. And as the air quality declines, the health risks rise. Those in areas of high air pollution are being warned to not spend extended periods of time outdoors, look into using an air purifier on indoor spaces, and don a face mask whenever possible — specifically, one that is rated to filter out at least 95 percent of tiny particulate matter.

Fire ecologist Professor David Bowman, in conversation with the ABC about the current NSW bushfires, offered a bleak warning for people living in areas with poor quality air.

"People will have died and more will die from the air pollution.” he said. “It's extremely serious."

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