Dr Chris Malley

How did you begin working in your area of research?

About ten years ago, I was working on my PhD, focusing on air pollution levels at two sites in the UK. During that time, I began to see the broader social and environmental consequences of what we put into the atmosphere. This realisation sparked my interest in how we can stop treating the atmosphere like a sewer and find better ways to handle our emissions.

I met Professor Kevin Hicks at a conference and he introduced me to the Stockholm Environment Institute (SEI). Since joining SEI at the University of York, I’ve seen how important it is to understand our impact on the atmosphere.

The air we breathe has a profound effect on our health, climate and food security. Over the past decade, my focus has shifted from a narrow regional and scientific perspective to a broader understanding of our overall impact on the atmosphere. This journey has reinforced my belief that changing how we treat the atmosphere is key to addressing both social and environmental challenges.

Can you tell us a bit more about your research?

My group focuses on finding and assessing strategies to reduce emissions into the atmosphere. We assess how these measures could not only reduce emissions but also improve public health by cutting exposure to air pollution. 

A recent project involved improving the way we assess health impacts of air pollution for the future. We reviewed traditional methods of predicting future deaths due to air pollution and pointed out their limitations, especially given the uncertainties around future mortality rates. To address this, we’ve proposed a new demographic model that offers a more consistent way to understand these relationships, potentially revealing greater future health impacts if current pollution levels remain unchanged.

We explore the crucial role of overall health in mitigating the impacts of air pollution. Most strategies focus on reducing exposure to air pollution, which is essential. However, we also believe that improving population health is significant in reducing deaths linked to air pollution.

Our current research shows that the main reason for fewer deaths from air pollution isn't just less exposure; it's also that people are healthier. It makes sense: healthier populations, with better access to healthcare, are less vulnerable to health risks like air pollution.

We stress the need for systemic changes to address the root causes of pollution, especially in low- and middle-income countries where pollution levels remain high. By integrating actions that enhance public health into air quality strategies, we aim to achieve the fastest reduction in pollution-related deaths.

What is the current global situation regarding air pollution and its impact on human health?

What I want people to understand is that air pollution is one of the biggest risk factors for human health and premature death worldwide. We’ve known this for at least 15 years. Despite this, air pollution is often underestimated as a health threat compared to other risks that get more attention. But that is changing, especially with recent findings from the Global Burden of Disease study.

This study assesses various risk factors that affect human health and quantifies the number of deaths linked to each risk. Over the past decade, air pollution has consistently been identified as one of the leading health risks. The latest report, released about a month ago, ranks air pollution as the second most significant health risk globally, highlighting the urgent need for attention and strategies to mitigate air pollution.

How does your research help us understand the impacts of air pollution and climate change, and develop plans to address them?

We work with countries to help them prepare and set climate goals and strategies, which are outlined in their nationally determined contribution or NDCs. For example, in Nigeria, we collaborated to enhance their climate ambitions: they now aim to cut greenhouse gas emissions by 47% by 2030. Through our analysis with Nigeria's Federal Ministry of Environment, they became the first country to quantify the health benefits achievable by implementing the climate goals in their contribution plan, which includes preventing around 30,000 premature deaths caused by air pollution.

By focusing on the human impact and local benefits, rather than just emission reduction targets, the plan becomes more compelling. The challenge now is ensuring these plans, informed by our research, transition from paper to action, especially in regions like Latin America, Africa and Asia, where funding is often limited. 

Our research also explores the link between agriculture, food systems, and their role in combating climate change and reducing air pollution. Agriculture is a significant source of air pollution, from ammonia in fertilisers and manure to emissions from burning agricultural residues and methane. This contributes to ozone formation, which can harm respiratory health.

In collaboration with the Climate and Clean Air Coalition and the Food and Agricultural Organization of the United Nations, our upcoming assessment will look at how changes in food production practices can help mitigate climate change and reduce air pollution. This includes not only technical changes but also systemic actions like reducing food waste and red meat consumption, which not only helps tackle climate change but also reduces agricultural air pollution and health risks associated with high red meat consumption.

Our focus is on finding strategies that offer multiple benefits, emphasising systemic changes over technical fixes, to comprehensively address air pollution.

How can we collectively address the critical issue of air pollution in our communities and beyond?

Air pollution is not an inevitable health risk. There are examples from places like Europe, North America and China where air pollution has significantly decreased over the past few decades. These cases show that we have effective strategies to combat air pollution and reduce its impact. But our approach needs to adapt to the urgent need to tackle climate change. High-income countries, especially those with a history of high emissions, must aim to halve global emissions by 2030 and reach net-zero by 2050.

Historically, efforts to reduce air pollution have relied on technical solutions aimed at specific pollutants, many of which also relate to climate change. Burning fossil fuels releases a range of pollutants, and while methods like particle filters in vehicles and stack filters on top of industrial chimneys help, they don’t address the carbon dioxide that contributes to greenhouse gas emissions.

To address both air pollution and climate change effectively, we need more systemic changes. For instance, prioritising walking, cycling and public transport over personal vehicles not only improves air quality but also cuts carbon emissions. This approach has multiple benefits: it helps mitigate climate change, promotes physical activity and better health, and reduces urban congestion by promoting shared public transport.

Find out more:

• Chris Malley's research
• SEI's research on air quality, climate and environmental change