Air Pollution and Mental Health: Q&A

With COP26 in full swing and the world focusing on climate change, we wanted to talk about the impact air pollution has on mental health.

We know that air pollution has a significant effect on our physical health. But there’s also a growing body of research connecting exposure to air pollution to mental illness.

We caught up with Dr Joanne Newbury, who worked on a paper researching the connection between long-term exposure to air pollution and mental health.

We spoke about the paper, how it wouldn’t be possible without interdisciplinary collaboration, and her hopes for the future of mental health research.

Joanne, could you tell us about the research you’ve been working on?

The project is a result of a successful linkage between detailed air pollution data and electronic health records from the South London and Maudsley NHS Foundation Trust. It was led by Dr Ioannis Bakolis, and my role was analysing the data.

There’s considerable variation in how people with psychotic or mood problems fare in terms of mental-ill health severity after onset. Some people have just one episode, others have multiple relapses over their whole life. It’s important to understand what factors could contribute to this variation.

There’s been growing evidence linking air pollution to mental health, particularly in the last five years. We speculated that air pollution could be one factor that might contribute to ill-health severity.

Together, we investigated this using the hospital records in a sample of over 13,000 people with first episodes of psychotic or mood problems, such as schizophrenia or depression, all living in four London boroughs, which are highly urbanised and also ethnically diverse. We analysed whether air pollution levels at their address were associated with how much people used mental health services after they had their first episode.

We used mental health service use as a proxy for severity because people with more complex health problems are likely to require more support from mental health services. After analysing the data, we found that people with higher air pollution exposure did go on to use mental health services more in the years after their diagnosis.

For example, 15 units increase in nitrogen dioxide was associated with between 18% and 32%, increased risk for having an inpatient stay or using community-based mental health services. This was after adjustments for confounders, such as for population density, deprivation, and age.

Seems like this project had lots of different people involved from different disciplines. Who did you work with?

It was a real mix. There were pollution modellers, psychiatrists, epidemiologists, bioinformaticians, statisticians to name a few. I don’t think that the study would have been possible without the contribution from experts from so many disciplines.

Why do you think this study wouldn’t have been possible without that mix of people?

For a start, modelling air pollution is really complicated. There are all sorts of complex data and methods that go into it. That takes a long time by itself, even prior to analysing the associations. Years of work went into creating the electronic health records in the South London and Maudsley, with experts in bio-informatics and natural-language processing. There’s much work that goes on, and I’m the lucky one who gets to analyse the data at the end

How did you find working with people from across a number of different disciplines?

I love it. You can draw on so many different areas of expertise, such as when it comes to the co-authors reviewing the manuscript and giving input. Everyone always has something important to contribute.

However, sometimes working across multiple disciplines means you can feel like a novice. You never really feel like you’re getting your teeth into one particular skill or field. That can contribute to the notorious imposter syndrome.

How do you envisage this research going on to make a real-world impact?

The findings add to growing evidence that air pollution might be detrimental to mental health. Crucially, thresholds for air pollution, such as those set by WHO, are currently based on physical health. We hope that thresholds will be updated to factor in impacts on the body and brain. We also believe that economic evaluations about air pollution’s impact should be updated based on its effects on mental health.

A useful starting point to reaching out to policy audiences often is through policy and public engagement teams within universities. They are really helpful and often have direct channels to relevant audiences. Although there are definitely still barriers between research findings and real-world implementations that need to be addressed.

For our study, we prepared press releases and interviewed with some major news outlets to try to increase the visibility of the findings. That was a good starting point because more people are likely to read news coverage of research than the original paper.

How would you like to see the research landscape change? Have there been things you’ve noticed which you want to see more of?

There are a few very important developments that are ongoing at the moment. For example, the Open Science movement in terms of trying to make research more transparent and reproducible. There are challenges, and it’s a difficult thing to get off the ground initially because whole industries need to change to support it.

Also, increasing diversity and inclusivity in mental health research is so important. In terms of both the people who conduct research, which is currently very poorly represented by minority groups and by researchers in the global south. And in terms of the people, we are researching.  From my perspective, thinking about the urban environment, mental health and air pollution, we need much more research in low and middle-income countries. Air pollution tends to be much, much worse in countries like India, China and Brazil. Also, that’s where most people live, and it’s where most of the urbanisation is going to happen.

Do you have any advice for a young researcher interested in interdisciplinary research?

Having a specific skill set that sets you apart is useful, such as a certain methodology or statistical approach. I think acquiring strong methodological training is a good way to go. And then the topics themselves can be interdisciplinary, as you can apply your method or skill to different research questions.

What about forging connections with other researchers who want to work across disciplines?

If you are in a team or university that has an outward-looking perspective and an interdisciplinary, collaborative ethos, that’s a great start. I think it probably becomes more commonplace to collaborate across disciplines as you become more senior and your research progresses. This is because your work begins to expand into areas you know little about, so you naturally look to draw on help from experts in other areas.

That’s really fantastic. Thank you for chatting with me today.

It was a pleasure. Thank you!

Did you catch Joanne in the Guardian this summer? Read the news story here. If you’re interested in reading more about interdisciplinary research, check out our blog with Professor Kamaldeep Bhui.