Mark Tebbs: Hello and welcome to the Mind The Kids podcast series. I'm Mark Tebbs and I'm your host for today. I've kind of spent my whole career working in mental health in different aspects from frontline service delivery through to being director of commissioning. At the moment I'm currently a chief executive of charity. So we're working with grassroots organizations and really focused on kind of community impact. My commission background makes me really interested in understanding need, lived experience and evidence-based practice. But I'm also a parent who's experienced the system from a parental perspective. So I'm delighted to be hosting this podcast. We get the opportunity to speak to researchers and practitioners trying to light on the latest research and to hopefully inspire you with some of those latest developments. Today I'm delighted to be speaking to Dr Sylvia Alemany, who's the lead author of an ACAM paper called Associations Between Air Pollution and Surrounding Greenness with Internalizing and Externalizing Behaviours Among Schoolchildren. So I'm really delighted to be joined by Sylvia. Sylvia, welcome to the podcast. Dr. Silvia Alemany: Thank you very much, Mark. I'm also very happy and grateful for your interest in our work. Mark Tebbs: Yeah, it's a super interesting paper. Do you want to just kind of like start by introducing yourself, maybe saying a little bit about your research interests and kind of where you work? Dr. Silvia Alemany: Yeah, I'm Silvia Alemany I'm a principal investigator in the research group of psychiatry, mental health and addictions from the Institute of Research of Valle d 'Hebron in Barcelona, Spain. And I'm in this team. This team is led by Marta Ribásés, Josep Antoni Ramos Quiroga. And the work you are interested in is actually led for the first author who is Uxue Zubizarreta- Arruti, one of the PhD researchers in our group. Mark Tebbs: Great stuff, excellent. So look, let's dive in. So it'd be really helpful just to set the scene for the listeners. So if you could just say a little bit about the overview of the study that we're talking about today. Dr. Silvia Alemany: Yeah, so I think that the main findings for our study was that in this population of around 4,500 individuals, actually children and adolescents from the general population of Catalonia, we observed that air pollution was related to more behavioural and emotional problems related to internalizing symptoms, while greenness was related to lower levels of externalizing symptoms that maybe later we can define with means internalizing and externalizing symptoms. But I believe this is the main findings. And one of the things that makes this study different from others, because this is an emerging area of research, and actually we are not saying anything really new. But more research has been done on adult mental health. And I think there's relatively scarce research on this type of physical environmental factors in child and adolescent mental health, especially at the level of symptoms and the level of general population. So not only in diagnosis, there's more research on ADHD or autism or spectrum disorders, but relatively there is less research on more kind of a dimensional approach to these symptoms. Regarding our particular setting, is also quite some papers studying similar objectives to ours in the city of Barcelona, but this is the first study covering the whole area of Catalonia, so one of the regions of Spain. So I think this is...first one covering this area and I think this is also important because it's out of only one city centre so it's also covering other regions, more rural regions from our territory. Mark Tebbs: Yeah, so I was looking at some of the research in London and we've got an ultra low emission zone across London, which has really impacted and improved the quality of the air. And the research seems to focus on older adults and respiratory problems. What was the inspiration behind you wanting to look at the issue of air pollution, child development and greenness? Dr. Silvia Alemany: Well, actually, it's totally true what you are saying. So I did a postdoc in the Barcelona Institute for Global Health that was my first contact with the topic of air pollution and the harmful effects on health. So I learned the history from air pollution. It's first linking that to respiratory issues, then more recently related to cardiovascular issues. And in the last two decades, more related to also neurodevelopmental and neurodegenerative disorders. So the more recent organ, let's say, that has been linked to these harmful effects from air pollution, it's the brain. And most of the research has focused, I think, so far more on the mention neurodegenerative effects. And there are very interesting results from Mexico from Dr. Calderon Garcidueñas. She did a very pioneering research on that, finding some hallmarks from Alzheimer's disease on the brain, post-mortem brain tissue of dogs, and then post-mortem tissue of children. So it was very shocking for science to see hallmarks of a disease typically seen in older populations already in children. So that inspired a lot of research on air pollution on brain. But most of the research has focused on adult mental health and adult, as I was saying, dementia. And probably in the last, I would say, in the last decade or even five years, there are more research on child and adolescence mental health going beyond this ADHD and autism. I think we are in a moment that we are finding typically some kind of studies with inconsistent results or negative findings. So I think it's a moment that we really need to increase the research on this topic to see how the evidences converge. it's also typical from environmental epidemiology and well, I also work with genetics, but especially in environmental epidemiology, we use different types of measures to capture and to estimate these environmental factors and also to assess mental health. So sometimes it's difficult to compare the studies and to see whether evidences are converging. So I think it's extremely relevant to continue doing this research. So this was in our agenda since we have this nice sample, and we have the schools and we could geocode the schools and see what was an estimate the exposure to air pollution and greenness at the level of the schools. Mark Tebbs: Yeah okay so tell us a little bit more about that so how did you go about conducting the study? I'm particularly interested in sort of how you measured air pollution, how you measured greenness if you could tell us a little bit how you went about that. Dr. Silvia Alemany: Yeah, sure. I'm not an expert in this. So this is what something we did in collaboration with IS Global, with the Barcelona Institute for Global Health. They are experts. this is, we have Antonia Valentin, we have Mireia Gascon, we have Jordi Sunyer in our paper, and we have Maria Foraster. And we needed these researchers to geocode the schools and then to estimate. So I mean, I estimate anything it's important because we are measuring the exposure. We don't have filters at the school that we can then analyse like doing some kind of chemical analysis. What we have is maps that have been modelled and there are different models. So we collaborate with these experts to try to choose which is the best model that we can use for our goal, for the goal of our study and for the characteristics of our study. So basically we have a map of Catalonia with the different, where you can put your geocoding sites where you want to estimate this different air pollutants or greenness or other measures. And what they do is when we give them a date, they can give us an average, an annual average for certain times in our case before the behavioural assessment. So we were able to study what we have an average of the 12 months before the behavioural assessment of the certain levels of different air pollutants and also a greenness around different buffers around centimetres around the school, 500 meters around the school. So these are estimations. So this may limit in some way the study, but we are using validated models. So they are based on mathematics, they are based on satellite images, and they are developed by experts on this. And this is also nice because we are seeing that our results kind of align with results that use another methodology, which is actually based on directly measuring at the schools, the air and greenness. So I think we can really rely on these estimations. So I think it's a bit difficult to understand this for the general population, but this is how we estimate the exposures. Mark Tebbs: I thought you explained it really well actually. So I was curious, and it's something I've not really thought about before, but so is the kind of air quality very localised? So within sort of close kind of neighbourhoods, you get quite big variations in air quality. Dr. Silvia Alemany: At the level of our study, and I have been asked about this before, because of confidentiality issues, because we don't want to alarm people, we were not doing anything related to localize any centre or a particular school where levels were particularly high. I'm also aware... that at least in Catalonia the government is studying this and is in contact also with the scientists who study this. So they also kind of monitor this. So in our study it was not our research question to make a difference between highly exposed let's say or schools comparing schools with higher levels to schools with lower levels. So we're just working with the individual level. And also because we were linking the exposure of the kid to the time where behaviour was assessed. So we were not comparing either rural versus urban or taking into account what I was saying, no more schools with a particularly high exposure. But definitely, this is something that I know authorities know and take into account, and also consult experts about this. And there might be differences. Also here, it's important to say that we assess a kind or a set of air pollutants. We try to be very comprehensive. So we use a particulate matter and nitrogen dioxide, but like the typical ones, but we focus on five types. So other studies only focus on one. We believe it was important to have a kind of comprehensive, different types of pollutants that are decreasing the quality of the air. But when we face the fact that we are studying Catalonia, we don't really know the sources of these different pollutants. So in the case of Barcelona City, previous research has indicated that traffic is the main source for these air pollutants. But in other regions, we are not sure about what is the source. So it is not our main goal now, or the main goal of this study, to focus on these schools that may be at particularly high risk. But definitely this is something important and I know authorities are aware of that. Mark Tebbs: Yeah, there's quite a lot of local campaigns just to try to get drivers to turn off their engines when they're waiting outside schools, for example. So I think that there is definitely more increased awareness and trying to be a little bit proactive around particularly the kind of traffic impacts here in the UK for sure. Okay. And then just greenness as well. Cause when I first read the paper, was expecting greenness almost to be like a, like shorthand for outdoor space but it is actually the measure of greenness as in UV light. So could you just talk a little bit about that? Dr. Silvia Alemany: Yeah, so I mean, the measure we use for greenness is this normalized vegetation index. So it's a very typical measure. It also can be a bit broad measure, but also this was our first paper on this line that we aim to continue. So we wanted to pick up an index that was widely used in the literature. We also wanted to see how our results, how our setting was working, whether we were finding something that's in line with the rest of the research. So what we are actually measuring is the amount of leaf vegetation, so green vegetation. And this is something done with satellite images. And then we have all the details in the paper. And again, we have these experts who because my main research line is genetic and environmental factors. So I really need to rely on people who is expert on this. And what we learn is that, is that this index is related to the amount of green vegetation. The actual factor that we see that is associated with lower levels of externalizing problems is the vegetation around 100 meters around the school. So that means more or less probably the vegetation that children and adolescents can see from their windows. So somehow this vegetation, it's either clean in the air or is either having some kind of relaxing effect on them. We don't know this. I'm just speculating based on previous theories, but this is what we observed. We observed a similar pattern for the vegetation at 300 meters and then at 500 meters. The significant association was at 100 meters. So this is just what they will probably seen from... from the windows, so probably even within the school, it was this green vegetation that seems to have some effect on their behaviour. So this is what we were measuring actually in this paper, but there are other measures and we plan to explore other measures for greenness. Mark Tebbs: Before we get into the results, I just want to unpack a little bit about the measurements of internalizing and externalizing behaviours. So just how did you define and sort of assess those in the paper? Dr. Silvia Alemany: Yeah, yeah, we use the CBCL, which is from the ASEVA. I'm not sure if I'm pronouncing this correctly, but it's a set of different instruments that parents, teachers, and adolescents can feel. So it's a self-reported instrument for adolescents. But in our case, we use the parent-reported instrument. So, pattern report on their children behaviour during the six months before. And it's a widely used instrument. And this instrument allow us to have different categories of emotional and behavioural problems. And in our case, we choose to use two broadband scales, which it is called. And it's because in childhood psychopathology in the field. you can work with these two broad categories of internalizing and externalizing. So internalizing symptoms refer to those symptoms that are like a psychological distress that is directed to the person, towards the person, to yourself, like depression or anxiety. This is something like you internalize this emotional distress while externalizing symptoms refer to those symptoms or behaviour that reflects some psychological distress that you direct outwards, so to your environment, to other people. So internalizing symptoms will include things like anxiety or depression. In the case of children, also somatic complaints like my stomach hurts, I have headache or things like that. And in the case of externalizing symptoms, this includes a more disruptive behaviour like aggressive behaviour or in our, in the particular case of this instrument is also delinquent behaviour like lies or stealing things, this kind of behaviour. this is kind of understood as emotional problems like are directed to the environment, to others. So we decided to use these two broad categories. Mark Tebbs: Okay, so what did you find? What was the association between greenness, air pollution, and internalizing and externalizing behaviours? Dr. Silvia Alemany: Yeah, so we found that air pollution, so two of the air pollutants that we were assessing, those with diameter of 10 micrograms and another one which includes 2.5 to 10 micrograms, so actually there are not the very, very small particles, were associated to more internalizing problems. While we found that greenness at the level of 100 meters that I was mentioning before, like more or less what they can see from the windows, was related to less externalizing symptoms. So that was our associations.

Mark Tebbs: So one was like a protective factor and one was ⁓ like a harm. Dr. Silvia Alemany: Exactly. Exactly. Mark Tebbs: So, was there an interaction between the two environmental factors? Dr. Silvia Alemany: Yeah, actually we don't analyse this. It's a very interesting point and this is something we plan to do. In our study, we did an exam in that, but it's one of the theories is that greenness may act through cleaning the air. So that may be one indirect effect of greenness. But there are other theories indicating that greenness can have a direct effect on behaviour, such as air pollution. It's very likely that we know from many evidences that air pollution have harmful effects on all the organs of the body. And greenness, for greenness, we have different theories. For instance, greenness may have some kind of direct effect. They talk about restorative effects, like relaxing the... the body and the mind and reducing the stress, but also through other factors. So more green spaces may also promote physical exercise or promote social interaction. And we believe that this is particularly interesting for our findings because we only find this association of greenness with aggressive behaviour with externalizing behaviour. So maybe this association might be mediated by these factors by more physical exercise or more interaction with other people may help some kids or some adolescents to regulate their emotions that are more aggressive. But this is something I'm just speculating. This is something that if we can, we will try to further investigate in the future. Mark Tebbs: Okay, so I'd like to turn to a little bit about the implications of the research. So what do these findings kind of suggest in relation to kind of like urban planning? So I'm just thinking about, what schools can do to mitigate or enhance the kind of like well-being of their kind of children, young people. Dr. Silvia Alemany: Yes, totally. I think this is a very important aspect and all the research in this line have these implications for policymakers and for public strategies to promote and prevent mental health. So we know that I think it's very important to reduce the traffic around the schools and also take care of the paths or take care of those roads to the school to try to facilitate or to try to provide citizens and families with certain ways to get to the school, avoiding very busy roads and more greenness or more other roads that can be ideally with more green spaces. Also at the level of the schools, I think there can be changes in the playgrounds because also we have quite a lot of research also related to the sun and some of the materials that there is in the playgrounds. But I believe greenness is very important. And also, as we are talking now during the summer and we are experiencing these heat waves and everything, for climate change, I think it's also very important. So our findings in a way are relevant for child and mental health, but I think they are globally important for climate change and for planet. We talk more and more about planetary health and one health. So if the planet is not healthy, it is very difficult that humans are healthy. So all these strategies actually will have an improvement also potentially on climate change and all of us, and also on the temperatures. I think this will be one of the biggest topics in the next years probably, and also for mental health. So yes, think policymakers and authorities are aware of this, probably not doing enough, but there's a lot of strategies to mitigate these effects and to provide citizens, I think it's very important to provide citizens with economic and with quality public transport networks and to provide the spaces to leave the car and have an easy way to get to the centre of the city.

But I cannot avoid to say as a scientist, as a citizen, that it's very important that authorities promote global changes. So they think globally, because I think it will be very, very bad if any of these strategies increases socioeconomic inequalities. So it is very important, I think, to take into account that not everyone can afford paying parking or arriving at certain times or certain things. So I think it's very, very important that they think in a global way about really have cities, with economic and really good public transport network and easy way to get there, not only for the people within the city, but also from the people outside the city. Mark Tebbs: Yeah, I think it's really important that we're joining up that green agenda with well-being, the kind of physical and mental well-being of the whole population. I guess what I of quite liked about the study was, you know, because the impact of the greenness was kind of very local, it felt like there were opportunities to, empower schools and young people to change their physical environment, hopefully whilst the... the national global picture is addressed by our politicians and leaders. Dr. Silvia Alemany: Exactly. Mark Tebbs: So I'm just wondering about messages to parents who are concerned about this this issue. Is there anything that the paper suggests that would be kind of good advice for parents? Dr. Silvia Alemany: Well, I believe for parents and family and school staff, it's very important to take into account that the effects that we are seeing are small effects. So hopefully the effects at least on mental health are small effects. So the important message is also to understand that mental health problems are multifactorial. So there's all the evidence so far points toward different factors taken into account in order to finally observe a kid or adolescents with a diagnosis or with severe or important mental health issues. And probably behind these or underlying these problems, are different kind of factors. So I think it's very, very unlikely that these physical environmental factors can totally explain complex disorders like ADHD, like Autism Spectrum Disorders. So this is to try to temper our message and to not concern families and parents that the effects are small. But the importance of this effect is because the exposure is global. So it's a large proportion of the population exposed. So even if we make a very small or marginal change in these exposures, we may a little bit decrease the risk for future mental problems or even in the adulthood while we are protecting the planet and protecting other aspects of the health. So, and also for parents and families, of course, there are individual measures that they can do. And if they are particularly concerned about, for instance, the location of the school of their children, there are associations, they can go to the authorities. There is more and more citizen science ways to engage citizens with scientists so we can together work to find a way for some particular cases or any concerns that citizens have. also, as I was saying, it's just important to try to avoid very busy roads with a lot of traffic. And we know that just putting a little bit of distance between the sources of these air pollutants, like by vehicles, decreases a lot the exposure. So just to try to be a little bit far from these roads and as much as you can, try to expose to the children to natural environments and to be in contact with greenness and also with rivers and with blue environments. We believe it's in general a good advice for mental health. Mark Tebbs: Yeah, that's really helpful. I think that gives a real balance perspective on the work and the area. I'm just thinking about future research. So is there any future research you're planning in the area? Dr. Silvia Alemany: Yeah, actually for us this is like our first paper from our group and in this sample. So we plan to continue investigating these effects and we have now, we have more participants, have, we are lucky that we have more participants so we will be able to have more power. And we are very interested in seeing any potential moderating effects. As I was saying, if we are capable of trying to investigate any mediator effects by physical exercise or moderating effects from genetic susceptibility, we are a group, we are more experts on genetic factors. So to me, it will be really, really nice is if we can see if there is any individuals that can be more vulnerable to these factors because that will give us some clues about the mechanisms involved from these associations which is I think something that it is still unclear how these physical environments can get into the body can finally affect the brain and and we can see these associations. And also, as I was saying, we are also very interested in the role of socioeconomic status. So we will continue trying to see whether these effects are different or act as a function of sex, of age group, and also of socioeconomic status. This is something that we will continue investigating. And also other outcomes we plan to investigate these effects on school performance. For instance, we believe this is very important and we may investigate also some diagnosis because we also have a screening and we have very nice data for this sample. So we may also try to see other mental health outcomes more clinically relevant, let's say. Mark Tebbs: Yeah, okay. We're coming to the end of the podcast. So I'm just wondering whether there's like a final take home message or if there's anything you want to say that we haven't had the opportunity to speak about. Dr. Silvia Alemany: I think I can summarize them in finding like air pollution seems to be, or we are contributing to the line of research, like suggesting that air pollution can be a risk factor for mental health during childhood and adolescence while greenness may be a protective factor, which we believe is very important because these are factors that can be modified so we can actually intervene, while authorities can help to intervene on these factors. And as I was saying, I would like to highlight that the effects are small. They matter because the exposure is global. But these are multifactorial outcomes. So there are other factors really important, but because of their impact in global health, we will continue investigating the role of these physical environmental factors on mental health. Mark Tebbs: Thank you, Sylvia, for such an interesting conversation and good luck with your future work in this really important area. So thank you very much. Dr. Silvia Alemany: Thank you very much for inviting me to this podcast. Mark Tebbs: So if you've enjoyed the podcast then please give us a rating or review on your favourite platform. Thank you very much.