Interview with Dr. Yiwen Zhang—Winner of the Environments Best PhD Thesis Award
1. Could you please give us a brief overview of your research topic? What motivated you to pursue this research topic?
My PhD research examined how fine particulate matter from wildfire smoke, known as wildfire-specific PM2.5, affects health from pregnancy through childhood and adolescence. Drawing on large health datasets across six countries, I investigated its associations with adverse birth outcomes, children’s mental health emergencies, and hospitalisations, including when wildfire smoke occurs alongside extreme heat. A key feature of my research was distinguishing particles from wildfires from those produced by other sources, to better understand whether their health risks differ and which populations need greater protection.
My motivation was strongly shaped by Australia’s 2019–2020 Black Summer bushfires. The scale of the disaster made me think about the less visible health consequences of wildfires, including those affecting people far from the flames. I wanted to understand whether the health burden of wildfire smoke was greater and more wide-ranging than we had recognised. The prospect of worsening wildfire risks under climate change gave these questions a particular sense of urgency.
On a personal level, as a woman, I have always felt a strong concern for maternal and child health, an interest shared by my supervisor. This concern became a research priority as I realised how much remained unknown about wildfire smoke exposure during pregnancy and childhood. Although respiratory effects had received considerable attention, much less was known about outcomes such as preterm birth and children’s mental health. I wanted my research to help address these gaps and provide evidence that could support better protection for pregnant women and children in a changing climate.
2. What was the most significant challenge you faced while conducting your PhD research, and how did you overcome it?
The most significant challenge for me was learning to navigate uncertainty while becoming an independent researcher. My PhD involved working with large datasets, learning complex statistical methods, and coordinating international collaborations. These were demanding tasks, but equally challenging was learning how to keep moving forward when research stalled or papers were rejected, sometimes after several rounds of revision. There were moments when the lack of external recognition made me question my own abilities.
My supervisors’ support made a real difference. They offered reassurance during difficult periods and encouraged me to explore different approaches. When a manuscript was rejected after multiple revisions, they supported me in making a carefully reasoned appeal where we felt there were grounds to do so. Knowing that their support would continue even if the appeal was unsuccessful helped me develop the confidence to stand behind my work while remaining open to criticism.
I also came to understand that a PhD is very different from earlier stages of education. It requires you to identify problems and work towards solutions independently, often without knowing whether an approach will succeed. My way of dealing with this was to persist: to consider feedback carefully, keep learning, and take the next manageable step, even when I did not feel completely confident in myself.
Over time, I learned that persistence does not require complete certainty. Sometimes, it means giving yourself the opportunity to work through doubt and find a way forward. That has been one of the most valuable lessons of my PhD.
3. What advice would you give to students starting or coming to the end of their theses?
For students starting their theses, I would encourage them to spend time understanding why their research question matters, rather than feeling that they need to have everything figured out from the beginning. Learn the foundations of your methods, stay curious, and ask for help when you need it. Becoming an independent researcher does not mean doing everything alone. Discussions with supervisors, colleagues, and collaborators can help you recognise problems and see possibilities you might otherwise miss. Discussions with supervisors, colleagues, and collaborators can help you recognise problems and see possibilities you might otherwise miss. At the same time, remember that people bring different perspectives, and you do not need to adopt every suggestion. Learning to evaluate feedback critically and decide what is appropriate for your research is part of becoming an independent researcher, and that judgement develops with time and experience.
For those approaching the end, my advice is to step back and recognise what your work contributes. When you have spent years immersed in a topic, it is easy to focus on its limitations and lose sight of how much you have achieved. A thesis does not need to answer every question; it needs to make a clear, well-supported contribution. Give yourself time to bring the studies together and explain what they collectively add to the field.
At both stages, try not to let a rejection or a difficult period become a judgement on your ability or worth. Take feedback seriously, but give yourself room to learn from it without expecting yourself to get everything right immediately. You do not have to feel confident every day to make progress. Keep taking manageable steps, stay connected to the people who support you, and look after your wellbeing along the way.
4. Would you like to share your experience with Environments and explain what motivated you to apply for the Environments Best PhD Thesis Award?
I first learned about the Environments Best PhD Thesis Award through a senior colleague who shared the opportunity with me. After reviewing the eligibility criteria, I felt that my thesis was a good fit and decided to apply. My research connects wildfire air pollution with maternal and child health, so I saw the award as an opportunity to share this work with a broader environmental research audience.
Preparing the application also gave me an opportunity to step back and reflect on my thesis as a whole: how the individual studies connected, what they contributed to our understanding of wildfire smoke, and how the findings could inform efforts to protect vulnerable populations.
I am very grateful to receive this recognition from Environments. It is encouraging to see this area of research recognised, and I appreciate the opportunity through this interview to share both the findings and the experiences behind the work.
5. How do you plan to continue building on your research in the future, and what are your long-term career aspirations?
I plan to build on my PhD by broadening my research to examine how climate change and environmental exposures affect population health. This includes air pollution, extreme temperatures, and other climate-related hazards, with a particular interest in how these exposures interact and how their health effects differ across populations and settings. Maternal and child health will remain an important focus, alongside other populations that may be especially vulnerable.
I am also interested in understanding the longer-term health consequences of environmental exposures and why some communities bear a greater burden than others. Through international collaborations, I hope to strengthen the evidence across diverse regions, particularly those that are highly exposed but underrepresented in research. Ultimately, I want this work to help identify opportunities for prevention and inform effective, equitable climate adaptation.
My long-term aspiration is to lead an independent research programme at the intersection of climate change, environmental health, and public health. I hope to work closely with practitioners and policymakers so that my research addresses the questions they face and contributes to practical decisions that protect health. I would also like to mentor younger researchers and offer the encouragement and support that have been so valuable in my own development.