Could air pollution be damaging your mental health?

Another lovely day in east London. Image: Getty.

Between 1 and 8 January 2017, London breached its annual air pollution limits. In just a week, the city broke EU regulations that limit nitrogen dioxide (NO2) emissions, which are produced by diesel vehicles. It is a publishable, verifiable, undeniable scientific fact that this gas is connected to heart and breathing problems. The UK’s air is dirty, and it is prematurely killing us. But can it also make your life more difficult in the meantime?

DepressionanxietyAlzheimer’spoor academic performance – these are just some of the things that scientists have connected to air pollution in recent years. Research is relatively young, and it is dangerous to establish cause and effect too freely, but it now seems apparent that the smog affecting our bodies could also be affecting our brains.

“Our study found that those with higher exposures to fine particulate matter, a type of air pollution, were more likely to experience high anxiety symptom levels,” says Dr Melinda Power, a professor at George Washington University who warns against establishing causality too early. In 2015, Power published her research, which used data from 70,000 women in the Nurses’ Health Study who then filled out a survey on their anxiety levels. She discovered that fine particles in the air (which come from, among other things, cars and factories) were connected to increased anxiety levels, and that the more recent the exposure, the higher the level of anxiety experienced.

“As relatively little research has been done on the relationship between air pollution and mental health, further research is needed to confirm our findings,” she says, noting that women in more polluted areas may experience other stresses that caused their anxiety.  

When it comes to identifying a cause for the recent epidemic in mental health disorders, such as anxiety and depression, often simpler explanations get precedence in the media. The idea that social networks like Facebook “make us” depressed has been flying around for years. This is easy for individuals to identify as an affect on their mental health, if it is affecting them that way. But not many of us stop to consider how the invisible air around us might be affecting our mental health, and it is much harder to find any anecdotal evidence of whether this is the case. For more answers, we must turn to science’s most faithful research assistant: mice.

“We got into this research by accident,” says Dr Randy Nelson, a professor at the Ohio State University Wexner Medical Center. “I was walking across campus and saw a trailer that was being used to expose mice to particulate matter. The work was being directed by a cardiologist who had demonstrated that exposure to fine airborne particulate matter caused inflammation in the heart.

“It seemed reasonable to hypothesise that exposure to this type of air pollution would also cause inflammation in the brain and that is often associated with depression and cognitive impairments.”

Nelson and his team exposed mice to fine particle air pollution in the same high levels that are found in urban areas. They discovered that, after ten months, mice exposed to polluted air took longer to complete a maze task than mice exposed to filtered air. More incredibly, the “polluted” mice also exhibited depressive symptoms and “behaviour despair”, such as an unwillingness to swim when placed in water. Researchers at Duke University also found pregnant mice exposed to diesel exhaust had offspring who exhibited increased anxiety.

When I ask Nelson if rising levels of air pollution could be causing rising levels of depression, he says it is “possibly a contributing factor” and points towards other environmental factors – such as bright lights at night interrupting our circadian rhythms. Like Power, he feels that more research needs to be done before such wide-reaching conclusions can be drawn.

But just how much research will be enough to prompt us to act? In 2015, scientists at the University of Utah found a link between air pollution and suicide in middle-aged men. It is also already proven that air pollution affects our physical health, and Power notes that this, in turn, can affect us mentally. “Air pollution may be related to mental health, particularly anxiety, through effects on oxidative stress and systemic inflammation or through promotion or aggravation of chronic diseases,” she says. Put simply, being sick can make us depressed.


(Side note: according to the psychologist Dr Ken McLaughlin, the current “politics of fear” can also increase anxiety, so reading about air pollution also probably doesn’t help. Sorry about that.)

And yet while research about how air pollution affects mental health is in its infancy, there is significantly more information about the link between air pollution and cognitive health. Power has found that men with higher past exposures to traffic-related air pollution had worse cognitive functions. An extensive 2012 article by the American Psychological Association outlines the many studies in this area.

So where does that leave us? A spokesperson for the European Commission, which sets our air quality targets, says the World Health Organisation is now reviewing evidence about mental health, and new targets will take this into account. Power says more “big, high-quality, longitudinal studies are needed”, yet Andrea Lee, a healthy air campaigner for ClientEarth, says we need to act sooner rather than later. “As research continues in all of these areas, what is beyond doubt is that air pollution in the UK is above legal limits,” she says.

Whether they are linked or not, it now clear we are facing two public health emergencies that need more attention. Mental health disorders and air pollution can both prematurely rob us of our lives. Depression can feel like a black cloud that bears down on you from all angles, smothering your entire being. Coincidentally or not, so can smog.

Amelia Tait is a technology and digital culture writer at the New Statesman, where this article previously appeared.

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What’s up with Wakanda’s trains? On public transport in Black Panther

The Black Panther promotional poster. Image: Marvel/Disney.

Black Panther is one of the best reviewed superhero films of all time. It’s instantly become a cultural touchstone for black representation in movies, while shining a positive light on a continent almost totally ignored by Hollywood. But never mind all that – what about the trains?

The film takes place in the fictional African country of Wakanda, a small, technologically advanced nation whose power comes from its main natural resource: huge supplies of a magical metal called vibranium. As is often the case in sci-fi, “technologically advanced” here means “full of skyscrapers and trains”. In other words, perfect Citymetric territory.

Here’s a mostly spoiler-free guide to Black Panther’s urbanism and transport.

City planning

It’s to the credit of Black Panther’s crew that there’s anything to talk about here at all. Fictional cities in previous Marvel films, such as Asgard from the Thor films or Xandar from Guardians of the Galaxy, don’t feel like real places at all, but collections of random monuments joined together by unwalkably-wide and sterile open spaces.

Wakanda’s capital, the Golden City, seems to have distinct districts and suburbs with a variety of traditional and modern styles, arranged roughly how you’d expect a capital to be – skyscrapers in the centre, high-rise apartments around it, and what look like industrial buildings on its waterfront. In other words, it’s a believable city.

It’s almost a real city. Image: Marvel/Disney

We only really see one area close-up: Steptown, which according to designer Ruth Carter is the city’s hipster district. How the Golden City ended up with a bohemian area is never explained. In many cities, these formed where immigrants, artists and students arrived to take advantage of lower rents, but this seems unlikely with Wakanda’s stable economy and zero migration. Did the Golden City gentrify?

Urban transport

When we get out and about, things get a bit weirder. The narrow pedestrianised sand-paved street is crowded and lined with market stalls on both sides, yet a futuristic tram runs right down the middle. The tram’s resemblance to the chunky San Francisco BART trains is not a coincidence – director Ryan Coogler is from Oakland.

Steptown Streetcar, with a hyperloop train passing overhead. Image: Marvel/Disney.

People have to dodge around the tram, and the street is far too narrow for a second tram to pass the other way. This could be a single-track shuttle (like the former Southport Pier Tram), a one-way loop (like the Detroit People Mover) or a diversion through narrow streets (like the Dublin Luas Cross City extension). But no matter what, it’s a slow and inefficient way to get people around a major city. Hopefully there’s an underground station lurking somewhere out of shot.


Over the street runs a *shudder* hyperloop. If you’re concerned that Elon Musk’s scheme has made its way to Wakanda, don’t worry – this train bears no resemblance to Musk’s design. Rather, it’s a flying train that levitates between hoops in the open air. It travels very fast – too fast for urban transport, since it crosses a whole neighbourhood in a couple of seconds – and it doesn’t seem to have many stops, even at logical interchange points where the lines cross. Its main purpose is probably to bring people from outlying suburbs into the centre quickly.

There’s one other urban transport system seen in the film: as befitting a major riverside city, it has a ferry or waterbus system. We get a good look at the barges carrying tribal leaders to the ceremonial waterfalls, but overhead shots show other boats on the more mundane business of shuttling people up and down the river.

Transport outside the city

Unfortunately there’s less to say here. Away from the city, we only see people riding horses, following cattle-drawn sleds, or simply walking long distances. This is understandable given Wakanda’s masquerading as a developing country, but it makes the country very urban centric. Perhaps that’s why the Jabari hate the other tribes so much – poor transport investment means the only way to reach them is a narrow, winding mountain pass.

The one exception is in freight transport. Wakanda has a ridiculously developed maglev network for transporting vibranium ore. This actually follows a pattern seen in a lot of real African countries: take a look at a map of the continent and you’ll see most railways run to the coast.

Image: Bucksy/Wikimedia Commons.

These are primarily freight railways built to transport resources from mines and plantations to ports, with passenger transport an afterthought.

A high-speed maglev seems like overkill for carrying ore, especially as the film goes out of its way to point out that vibranium is too unstable to take on high-speed trains without careful safety precautions. Nevertheless, the scene where Shuri and Ross geek out about these maglevs might just be the single most relatable in any Marvel movie.

A very extravagant freight line. Image: Marvel/Disney.

Perhaps this all makes sense though. Wakanda is still an absolute monarchy, and without democratic input its king is naturally going to choose exciting hyperloop and maglev projects over boring local and regional transport links.

Here’s hoping the next Black Panther film sees T’Challa reforming Wakanda’s government, and then getting really stuck into double-track improvements to the Steptown Streetcar.

Stephen Jorgenson-Murray tweets as @stejormur.

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