Health Voices

Wild, Wild Air Waves

• Season 1 • Episode 2

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What do you think environmental health means?

According to the American Public Health Association, most Americans can’t give an accurate answer for it’s one of those underrated yet complex fields of public health. With Yiqun Ma, a pre-doctoral fellow at the Yale School of Public Health concentrating in climate change and health, we discuss the importance of environmental health.

We specifically talk about how a particular aspect of public health, the air, correlates with adverse temperatures, wildfires, and racial disparities.

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00:00: Intro
2:07: Definition of Environmental Health and Climate Change
5:55: Jiangsu Province Research on Adverse Temperatures
10:32: Wildfires
14:31: Racial Disparities and Air Pollution
22:32: Yale’s and Government’s Role in Bolstering Enviornmental Health
26:30: Conclusion


Fareed Salmon:

Welcome to Health Voices, a podcast from the Yale Public Health Coalition, where we discuss the breadth and depth of public health and how it actually impacts the individual in the New Haven area and beyond. My name is Fareed Salmon.

Sahil Chhabra:

And my name is Sahil Chhabra.

Fareed Salmon:

And you welcome me to the first episode of Health Voices. We wanted to begin with what we believe is a hidden gem of public health that a lot of people overgeneralize or misunderstand, which is environmental health.

Sahil Chhabra:

According to the Public Health Association, environmental health isn't known to most Americans, and how the environment affects public health is an unfamiliar concept.

Fareed Salmon:

And so to understand environmental health and how it affects us. We're talking with Yiqun Ma, a pre-doctor fellow in the Department of Environmental Health Sciences at the Yale School of Public Health. We discuss not only environmental health as a definition, but the correlation between climate change, status quo and human health. This includes topics from wildfires' smoke's association with asthma in New York City to racial disparities in air pollution.

Sahil Chhabra:

Let's dive in. Miss Yiqun Ma, thank you so much for taking the time to be on the first episode of Health Voices. How's your day been?

Yiqun Ma:

Good. I was writing a manuscript on a study of the COVID-19 lockdown and air quality changes, as well as the associated health benefits.

Sahil Chhabra:

Awesome, and have you been working on this work recently?

Yiqun Ma:

I've been working on this since two years ago, but it's now come to a conclusion and we are writing the manuscript and ready to submit it to a journal.

Fareed Salmon:

That's really exciting. Thanks so much once again for taking the time to come out here today. Let's dive into the episode. Mrs Ma, please tell us what is your role in the School of Public Health at Yale.

Yiqun Ma:

I'm a PhD candidate in the Department of Environmental Health Sciences. I mainly study of air pollution, climate change and human health.

Fareed Salmon:

Obviously, you dedicated most of your life, I guess, to environmental health. Why do you think environmental health is important to you?

Yiqun Ma:

Environmental health is about the intersection between the environment and our human health. My main focus again is air pollution and climate change, but environmental factors also include lots of other things like water quality, chemicals, radiation, green spaces and so on. To me, it's not just a one-way thing. It's not only about how these factors impact our health, but also about what we can do to create a better and healthier environment for ourselves. And why is environmental health important?

Yiqun Ma:

First, environmental hazards can lead to a wide range of health outcomes. For example, poor air quality is associated with a lot of diseases, from acute respiratory symptoms to chronic heart diseases. Second, many environmental risk factors can harm everyone, regardless of how healthy your lifestyle is. Let's say, you live a very healthy lifestyle, eating healthy food and doing exercises every day, but when wildfire smoke arrives in New Haven, you can still be affected. And third, although everyone can be affected, some people may be more vulnerable. Environmental health challenges disproportionately affect vulnerable populations such as children, pregnant women and older adults, who are more physically vulnerable, and racial minorities and low-income people, who are more socially vulnerable. Addressing these challenges is crucial for achieving an equitable and sustainable society.

Fareed Salmon:

So, with this definition in mind, a lot of people think that environmental health is about how we affect the environment and also about how the environment affects us as well. Can you please reflect on that as well?

Yiqun Ma:

The impact of environment on our health is complicated and it's hard to summarize in one sentence. However, one of the most important pathways is through climate change, which is one of the most important environmental threats in recent decades and in the future.

Sahil Chhabra:

Okay, so could you give us a definition for climate change and also, how is climate change related to environmental health?

Yiqun Ma:

Sure, to be honest, there are a lot of definitions of climate change, but let's use the simplest one. It refers to long-term shifts in temperature and weather patterns. For many people, the first thought upon hearing climate change might be about polar bears, but it's much more than that. Humans are also threatened by climate change. First, the direct impacts of climate change, such as heat waves, hurricanes, floods and other extreme heat events, usually have severe health implications. And second, climate change indirectly affects environmental determinants of health. For example, climate change can alter the distribution of vector-borne diseases like malaria. Rising temperatures can also worsen air quality, thus indirectly influencing human health.

Sahil Chhabra:

So, as you mentioned, climate change has an effect on temperature and this can be seen in different parts of the world, like your research mentions, for example, in the Jiangsu province in China. So could you discuss your research on the Jiangsu province, specifically the relationship between adverse temperature conditions and chronic diseases and mortality?

Yiqun Ma:

Yeah, so extreme temperature, in other words, extreme heat and cold, is one of the most direct impacts of climate change. Extreme temperature events are expected to be more frequent and more intense in the future under the changing climate. So will extreme temperature influence our health? In this study, using data from Jiangsu province, China, we investigated the association of heat and cold with mortality from a comprehensive spectrum of diseases, and we found that extreme temperatures are associated with a wide range of cost-specific mortality, such as myocardial infarction, stroke, hypertensive heart disease, COPD, diabetes and mental disorders. In total, about 12% of mortality was attributable to heat and cold.

Fareed Salmon:

Those numbers are just incredibly astonishing and from a medical perspective I guess how do these adverse temperatures actually make these health diseases more likely in humans?

Yiqun Ma:

The underlying biological pathways are different among different diseases and, to be honest, currently the mechanisms are not well understood for many diseases. For this question I can talk about the physiological pathways for cardiovascular diseases, as they are relatively clear so far. So the relationship between heat and cardiovascular mortality can be explained by the dysfunction of thermal regulation. Exposure to extreme heat can cause increased blood circulation and sweating, inducing dehydration and elevated blood viscosity, which increases the risk of cardiovascular mortality, and, on the other hand, for low temperature, cold can lead to vasoconstriction, resulting in an elevated blood pressure and therefore higher risk of cardiovascular mortality, especially when we talk about hypertensive diseases, which is directly associated with blood pressure. But for many other diseases, such as diabetes and the nervous and mental diseases, the pathways are still being studied by many other researchers.

Fareed Salmon:

So do you think that the average temperatures are caused by human-caused climate change, or do you think that is intrinsic to the actual geography of this province in China?

Yiqun Ma:

Mostly by human behaviors, but of course you cannot totally exclude the natural sources.

Fareed Salmon:

So do you think that these results that you found in China can be found in different areas of the world as well?

Yiqun Ma:

Yes, of course. Actually, there are many previous studies conducted in many other countries in the world. There's a collaboration called the Multicountry Multicity Study. They collect data from different countries across the world and they found similar findings..

Fareed Salmon:

Oh, wow. So from a public health perspective, right. How do you think that we can begin to address these average temperatures? Do you think that we should go to the direct source, or do you believe that mitigating the effects of these average temperatures is the best way to go?

Yiqun Ma:

There are two strategies Broadly. One is called mitigation, like what you said directly go to the source, reduce carbon dioxide emission, and on the other side we can also adapt the adverse health impact. That's called adaptation. For example, we can turn on air conditioners during heat waves and go to cooling centers, things like that.

Fareed Salmon:

Okay, brilliant. So let's switch gears a little bit and, I guess, talk more about the immediate effects of climate change. Now, when a lot of people think about natural disasters, they think of floods, tornadoes and maybe earthquakes, and they are legitimate effects of climate change. However, arguably one of the more horrendous effects of climate change are wildfires. As you know, wildfires are more common in dry regions in the US, like in California, but recently they've been prevalent in the eastern region of North America. The first question is what is going on with wildfires in this region and why do you think this is happening?

Yiqun Ma:

Under the changing climate, wildfires are expected to be more and more frequent and intense, because the higher temperature and the air is getting drier in many regions. This increases the risk of the occurrence of wildfire.

Fareed Salmon:

In terms of the impacts of wildfires, do these occurrences only affect the site of the wildfire or can one wildfire, can it affect the felt across a region or a continent?

Yiqun Ma:

In fact, wildfires, the event itself, usually do not occur in the New England area. As we know, in the US, the California, the western US, is where the wildfires usually occur. However, the smoke from wildfires can travel thousands of miles away from the sources, thus, everyone in the US can be infected.

Fareed Salmon:

Oh wow. So due to climate change in the region of California and even Canada, smoke traveling can affect people thousands of miles away across different regions. So what are the immediate and long-term consequences of wildfires, both for the people that are affected in the wildfire region and for smoke as well across a region?

Yiqun Ma:

Yes, wonderful question. So wildfires have significant immediate as well as long term health consequences for both humans in the region where it occurs and people who live far away from the sources. In the short term, humans face direct consequences such as acute respiratory symptoms from smoke inhalation, as well as severe burn injuries and even fatalities in extreme cases. Wildfires can also trigger mental problems such as anxiety, depression and post-traumatic stress disorder, ptsd. And the longer term health impact of wildfires include chronic cardiovascular and respiratory problems. Some studies also indicate that mental effects such as PTSD and depression can persist in some severe cases.

Fareed Salmon:

Oh, wow. So with all those different health issues related to wildfires and with smoke, how do you believe that things like new haven can begin to address those issues?

Yiqun Ma:

Like if you were in New Haven in the summer, you must experience this wildfire smoke event. The smoke was traveled from Canada and in New Haven the sky turned copper-yellow and you can even notice the smell of smoke in the air. For residents in New Haven, what we can do is to protect ourselves from the health impact of smoke. For example, once we get the air quality alert, we can wear a mask, turn on air purifiers at home and try our best to stay indoors to reduce our exposure to wildfire smoke and protect ourselves.

Sahil Chhabra:

Awesome. Thank you so much for all your insight on wildfires. Now let's transition to a little bit different of a topic related to environmental health. Environmental health issues are not all happening in a vacuum. There's a lot of social context involved when we're talking about environmental health, such as the relationship between pollution and racial and residential disparities. That, specifically, is an area of research that you've conducted. Could you describe what you found out from your research about the relationship between the exposure to polluted air, cardiovascular disease and racial disparities?

Yiqun Ma:

Over recent decades, pm2.5 levels have fallen considerably across the US as a result of the National Clean Air Act, as well as other regional efforts. This improvement in air quality has brought substantial benefits to human health, especially to cardiovascular health. However, it's unclear for us whether these benefits, especially the benefits to cardiovascular health, distributed equitably across different racial ethnic groups.

Fareed Salmon:

And before we continue, what is PM2.5?

Yiqun Ma:

Oh yes. PM2. 5 is fine particulate matter, with diameters that are generally 2.5 micrometers and smaller.

Fareed Salmon:

And PM2.5, does that measure how much air pollution there is, or what does it exactly measure?

Yiqun Ma:

PM2.5 is the particle itself, but when we say PM2.5 concentrations it measures how much PM2.5 particles are there in the air.

Fareed Salmon:

Thank you for that explanation. Please continue.

Yiqun Ma:

Indeed, there are many previous studies examined this question and they found that an unequal distribution of PM2.5 exposure across communities, with racial minorities being exposed to disproportionately high levels of PM2.5. But the racial disparities in PM2.5 related mortality burden cannot be fully explained by the disparities in exposure. Due to systematic racism and its downstream social determinants, such as lack of access to healthcare resources, people of color may be more vulnerable to the health consequences of PM2.5. So in a recent study, utilizing the nationwide PM2.5 and cardiovascular mortality data, we examined different vulnerabilities to long-term exposure to PM2.5 among different racial groups and then assessed the PM2.5-related CBD mortality burden across different groups. So what did we find? This study found substantial racial disparities in both vulnerability, too, and burden of PM2.5-related cardiovascular mortality, and among all racial groups. Non-hispanic black people have the highest PM2.5-related mortality burden. And as the air gets cleaner over years, the total burden of PM2.5-attributable mortality burden greatly decreased. This is a very good news. However, although the overall burden decreased, the racial disparity in this burden still exists.

Fareed Salmon:

Do you believe that the recent uptake in wildfires and, as you said, smoke traveling thousands of miles, do you think that this uptake of wildfires can further exasperate these disparities in air pollution?

Yiqun Ma:

This is a very new research topic in our field and I know many researchers are working on it, but for now we cannot come to a consistent conclusion about whether wildfires increase or decrease the racial disparity, because the occurrence of wildfire is more because of natural drivers instead of social drivers.

Fareed Salmon:

So what are the social drivers for pollution in these areas and why they affect mostly non-Hispanic and non-white black people?

Yiqun Ma:

Yes, so studies show that people of color are typically exposed to higher levels of air pollution in the US, and this can be explained by redlining, inequitable sighting of emission sources such as highways and industrial facilities, and other policies and practice in their history.

Sahil Chhabra:

When we talk about the health of non-Hispanic black people compared to other racial groups, do you think the reason for the higher correlation of diseases with PM2.5 in this racial group is due to the same reasons that other racial health disparities exist that disproportionately affect non-Hispanic black people?

Yiqun Ma:

Yes, so when we talk about the higher mortality burden, or higher PM2.5 related mortality burden, in non-hispanic black people, one factor is, as we mentioned, the exposure, but on the other hand, the different vulnerability can also play a role. So why do black people have a higher vulnerability to the bad consequences of PM2.5? This still may be explained by structural racism and because it's not because they are physically more vulnerable, but more importantly is that they lack equitable resources to healthcare and education, so when, even when, they are exposed to the same level of air pollution as white people, they can face worse consequences.

Sahil Chhabra:

Got it and so you know. Are there ways that the government can produce policy that could potentially contribute to reducing, either reducing, specifically, the PM2.5 exposure of people of color or improving the health outcomes of, you know, non-hispanic black people as a result of PM2.5 exposure?

Yiqun Ma:

Yes, I think the primary responsibility lies with the government and it's crucial for policy makers to prioritize environmental justice when designing and implementing health. Designing and implementing health, air quality regulations and policies. Possible solutions include increased green space in the communities of people of color, shutdown or upgrade the high emission factories in those communities, and so on. And also, in addition to environmental policies, policies in other aspects, such as education and healthcare, should also be more equitable to reduce the disparities in vulnerability among racial groups.

Fareed Salmon:

What do you believe that the Yale School of Public Health can do to address not only the wildfire and smoke health issue but also, to the social context, what they can do to help reduce these disparities?

Yiqun Ma:

So first I must still up PhD students, and I can only speak for myself, not for the whole school. So from what I've observed, the professors and the research team in the school has already wonderful research regarding the environmental crisis and the racial disparity issues. But for me, I think the challenge is in sharing our findings out of the scientific community and, to you know, share and communicate our thoughts to a more general public. So like, how do we get important findings out to people and actually apply it to make a difference in the community? This is really a challenge and I know many people are really working on it, but still there's a long way to go.

Sahil Chhabra:

So you, just going off of what you just said, do you think that there is a gap in, you know, communication between you know bodies of public health, such as the Yale School of Public Health. You know how they inform the public. So you know, is there a gap, first of all, and if there is, then you know how is this affecting the overall public health of people and are there ways that this gap in communication could be addressed?

Yiqun Ma:

As far as I know, NIH is currently realized this problem and they are encouraging researchers to engage more with the community and make a real impact in the real world. They allocate some findings to especially support such projects and also, I believe media teams like your podcast and the Yale news also play a crucial role in in this process and for our researchers it's our responsibility to speak out and make our

Sahil Chhabra:

with public health how how information, in terms of what we've discussed today, with wildfires and, you know, air pollution, what can people do, you know, on their own, to try to protect their own health, as well as you know, the health of their families or the communities?

Fareed Salmon:

Especially in terms of, like those non-white black people or Hispanic people that may have less resources. What can they do to better their own environmental health?

Yiqun Ma:

That's a good question. So first, of course, our individuals can take actions to protect ourselves, like wear a mask when there's high pollutant in air, or like turn on air purifiers at home. But still, for me, I think it's the government who need to take more actions and is responsible to address this issue, because as an individual, we don't have such power to clean the air power cell.

Fareed Salmon:

That is so true. What do you, as a PhD student right now, what do you see yourself doing in the future, in t tenvironment jenvironment ?

Yiqun Ma:

I'm going to graduate next year and I will continue to work in this field as a postdoc researcher. I'm excited about the opportunity to contribute more scientific research in this field and I'm open to many other topics in climate change epidemiology. So far, I've worked on air pollution, but I'm also open to many other topics, such as floods, droughts, hurricanes and other climate change related events.

Fareed Salmon:

All right. Thank you so much, Mrs. Ma, for taking your time and coming out here today. Thank you, I appreciate it coming out for the first episode of Health Voices, the official Yale Public Health Pollution Podcast. Thank you so much.

Yiqun Ma:

Thank you for the invitation.

Frederick Rivas-Giorgi:

This is Frederick Rivas, georgie from Health Voices. Health Voices is a podcast produced by Spheri Salmon and Sahil Shabra with support from the Yale PhD Vice President, dylan Kim, and the entire PhD board. If you have any questions about the podcast or would like to be featured in an episode, please email us at YalePhcPodNews at gmailcom. That is YalePhcPodNews at gmailcom. Thanks again for listening today.