How air pollution impacts our brains

[MUSIC PLAYING] SABRINA SHANKMAN: Welcome.

My name is Sabrina Shankman.

I report on climate change at The Boston Globe.

And I'll be moderating today's discussion of air pollution and the brain.

I'm delighted to be joined by today's panelists.

Pleased to introduce Maite Arce, president and CEO of Hispanic Access Foundation, Joe Allen, an associate professor of exposure assessment science and environmental health, and the director of the Healthy Buildings Program here at Harvard TH Chan School of Public Health.

Francesca Dominici, the Clarence James Gamble professor of biostatistics, population, and data science at the Harvard Chan School, and Marc Weisskopf, the Cecil K and Philip Drinker professor of environmental, epidemiology, and physiology also at Harvard Chan School.

Thank you all for being here.

A reminder that today, all the speakers here are going to be sharing their own views.

They do not speak for the school.

And thank you all for being here today in the audience.

So let's jump in.

An increasing amount of evidence has linked air pollution exposure to poor brain health, including cognitive decline and mood disorders.

Marc and Francesca, maybe you can start us off, what do we know about the connection between the air we breathe and our brains?

[INTERPOSING VOICES] FRANCESCA DOMINICI: OK, I'll start.

Well, there is more and more emerging evidence that especially long-term exposure to air pollution increase incidence and progression of Alzheimer's disease, and Parkinson's, and other neurocognitive disease.

The work I've been conducting together with many colleagues here at the School of Public Health, I've been basically analyzing the entire national healthcare system, the Medicare and Medicaid claims. We've been following several individuals over time, several million of individuals over time assessing their long-term exposure to fine particulate matter.

And so very briefly, then I can say more about it, but what we are finding from this study with enormous statistical power is that long-term exposure to fine particulate matter increases the incidence and hospitalization of Alzheimer's disease.

It also increases the progress session in terms of rehospitalization of Alzheimer's disease.

And also we are seeing that among people that are diagnosed with Alzheimer's, exposure to fine particulate matter tends to increase the rate of hospitalization for all causes and also increase risk of mortality.

SABRINA SHANKMAN: OK, Marc?

MARC WEISSKOPF: And I guess if I can add from a sort of biological perspective, I mean, I think sort of the exploration of air pollution in the brain is relatively new.

It's newer than many other outcomes.

And I think one of the early things that got people interested in thinking this might be going on was the wealth of data that exists already on things like cardiovascular effects of air pollution, which there's a lot of data behind on many levels.

And the brain is, frankly, hugely dependent on the cardiovascular system.

So if the cardiovascular system is affected, we think there could be impacts on the brain.

And I think that started-- that sort of was at the origins of the interest that maybe something's going on there.

And we do know that can absolutely happen.

And that is one of the things that-- one of the ways the brain can be impacted through air pollution.

There's a lot of interest now, and it's an active area of exactly what biology is happening with these particles.

But there's-- particles can generate sort of inflammatory immune effects in the systemic circulation that can get to the brain.

There's some ideas that the particles can get to the brain directly, actually, not just through these secondary effects.

And more recently, there's been a lot of interest on the idea that actually when you breathe in through your nose, you're smelling things because you've got neurons that are sticking out in the world, exploring it that way.

And we now understand that some particles, or aspects of particles can actually get transported directly back into the brain, so skipping the lungs and the cardiovascular system.

So that's an almost more immediate route.

And people have seen in dogs from Mexico City versus a cleaner part of Mexico, you can sort of see effects that we believe to be the particle type effects going on in the brain and sort of evidence there that something is happening.

But it's a very active area of research as to this very specific biology of what may be going on.

But there are many things that could be happening.

SABRINA SHANKMAN: That's fascinating.

We're going to ask a little bit more about that in a little bit because that is a really interesting area.

But it's not-- it's not just these kinds of effects that we've seen.

I understand there's also a link to anxiety and depression from poor air quality.

And that that's shown up in school performance too.

Joe, could you talk a little bit about the acute effects on cognitive tests that you've seen?

JOE ALLEN: Yeah, for sure.

So we actually had a program right here at the School of Public Health on the surprising link between air pollution and mental health.

And our team summarized the findings that you see largely in kids.

And we see air pollution linked with things like anxiety, suicide ideation, big studies of-- we see increases in pediatric hospitalizations related to psychiatric disorders linked to air pollution.

My own work has been around indoor air quality, so another type of air pollution and cognitive function impacts.

So we've done studies of say office workers, where we've changed the air that were breathing, we introduced air pollution into their space, in this case, it was air pollution like off gassing from dry cleaning and dry erase markers without them knowing, in a double blind study.

And then we test their cognitive function performance.

And we see, they perform worse on these tests.

And these tests are things like how do I seek out and utilize information in the world?

How do I make strategic decisions?

How do I respond during a crisis?

And that was a double blind controlled study.

But then we did that same kind of study globally.

And we had about 450 office workers, and the same thing, we looked at indoor air quality and these cognitive outcomes.

And this will tie into the work here.

We actually saw a link between PM 2.5, so a main component of outdoor air pollution, and acute performance on these cognitive function tests.

So air pollution measured at your desk, most of which is coming from outside, and these acute tests.

So across all these dimensions, we have office workers, university workers, kids in elementary school, high school students, we see over and over the impacts of air pollution on the whole range of mental health, anxiety, all the way through higher order cognitive function.

SABRINA SHANKMAN: Wow.

And Maite, you've seen something related to schools, right?

MAITE ARCE: Yes, we have talked to parents in high Latino populated communities.

And high exposure to particle matter 2.5 increases-- it may increase the respiratory infections of children, which can lead to symptoms like asthma.

And that can lead to school absences.

And it can lead to less participation in school activity.

And so it's definitely a concern that parents have.

SABRINA SHANKMAN: What about when it comes to mental health, Marc?

You've looked at that a bit.

MARC WEISSKOPF: Yeah, so-- we did one of the first studies in the Nurses' Health Study looking at PM and its relation to anxiety symptoms there.

So absolutely, I mean, more of the focus is on kind of cognitive processing and for the knowledge economy, et cetera.

But all the kind of processing in the brain that is underlying how you learn, and remember, and how you function on a cognitive level is basically the same for mental health scenarios.

And possibly there, it's even-- can be considered more sensitive in a sense.

So if you disrupt the what's going on in the brain, you can put yourself into bad brain states.

And that can either exacerbate underlying problems. And this is a big issue what is actually occurring.

Is it an exacerbation of something that's underlying in there?

Or is it actually-- or both, is it actually contributing to a new development of something like that?

FRANCESCA DOMINICI: Yeah, I think just to add to what Marc is saying, from analyzing massive amounts of data, we are also seeing that exposure to greenness, and so being able to spend more time in green parks, actually

has a protective effect on hospitalization and progression of Alzheimer's disease.

We haven't looked specifically to mental health.

These are mostly studied in the elderly.

But it complements-- and it's consistent with what Marc is saying.

Now, we need to understand even better whether the access to the green space also means that there is a less particulate matter because you are in the park.

But we are actually seeing an evidence that even with the same exposure to particulate matter, if you are close to a park, or you're spending more time in park, the adverse effect of particulate matter on Alzheimer's is lower than if you don't have access to green space.

SABRINA SHANKMAN: Do you know what it is about that access to the park that is causing that?

FRANCESCA DOMINICI: Well, we are not studying the mechanism.

And we can't.

So not really.

But I think that could provide some hypothesis of what additional biological mechanism we want to study that will inform that protective effect.

But I mean, we do have tremendous amount of evidence of a positive effect of spending time in nature has a protective effect on mental health.

So I think it will be-- I will guess it will be a similar mechanism.

SABRINA SHANKMAN: Interesting, yeah.

Communities of color are often disproportionately exposed to pollution.

Here's an example.

More than 56 million Latinos live in the 15 worst urban areas with the most ground level ozone pollution.

So there's a clip from a video that we're going to watch from the Hispanic Access Foundation.

It's an interview with a woman who's been impacted by air pollution in Phoenix, Arizona.

[VIDEO PLAYBACK] - Hi, my name is Yara Marine.

And I'm from Phoenix, Arizona.

So I grew up in Phoenix, Arizona, specifically south central Phoenix, which is the epicenter of pollution and factories.

And as a result, I actually grew up having asthma.

And a lot of my cousins and my friends growing up did too.

And so it was very frustrating as I got older to learn that that was a direct result of the environment that I grew up in, the parks that I went to, and because I was exposed to a lot of those dirty fossil fuels and that pollution from living under highways.

And so as I've gotten older, it has really become important for me to do Latino advocacy especially around public parks, and outdoors, and ensuring that our Latino children and our community members have access to clean parks, where they can step outside enjoy our beautiful madre

tierra and not have to worry about having respiratory issues or being exposed to dirty fossil fuels and harmful fumes that can cause asthma.

[END PLAYBACK] SABRINA SHANKMAN: Maite, can you talk a little bit about how the Hispanic Access Foundation has been working with Latino communities on air pollution?

MAITE ARCE: Yes, we have just started a long range program called [SPANISH],, The Air That We Breathe.

And we've recruited citizen scientists from 12 communities who are members of our faith-based networks who have the trust of their communities.

And they are-- we they formed a cohort, a learning cohort.

Where they're connecting with their peers to talk about air pollution and also learning from experts in air quality.

These leaders, these citizen scientists are using air quality sensors in their churches to monitor and report air quality in their communities.

And then they're entering the data into an online mapping-- an online map.

They're also helping to work with us to develop materials that are tailored to the needs of their communities, who are primarily Spanish speaking, or immigrant communities.

And they're-- and they're disseminating that information in a variety of ways, from sermons at church services, to film screenings and roundtables, to community workshops, radio, and social media.

And then they're also supporting community in making practical changes to help improve their preparation when there's bad air quality days, like masking or staying indoors.

And then very importantly, which is something Yara mentioned in the film is they are advocates.

And so they're inviting elected officials, decision makers into their churches to hear their concerns.

And then they're also organizing in the community to really urge for policy change.

SABRINA SHANKMAN: So across the sites where you're monitoring, what have you learned so far?

MAITE ARCE: The biggest learning is how little to no knowledge there is about particulate matter 2.5.

We're starting at zero in terms of the knowledge.

People understand and are concerned and have been for a long time about the health and effects that they're seeing, and what they're seeing in their community.

But the understanding is just really eye opening for them and makes them feel that urgency to take action.

SABRINA SHANKMAN: Yeah, I mean, is there a lot known about those kind of racial and economic disparities when it comes to this?

Where is the research on that?

I don't know if-- I'm just-- if anyone.

FRANCESCA DOMINICI: Well, I mean, we published a study in Nature three years ago where we looked at exposure to fine particulate matter in the last 20 years by census tract in the United States and look at chronic exposure by the percentage of underrepresented and minority in that census tract.

And not surprising, what we saw is that although exposure to fine particulate matter thanks to the Clean Air Act has been decreasing over time quite a lot, actually, and that is definitely an excellent news, but we did see that the disparities.

And so underrepresented minorities, Hispanic, Latino, Black American consistently breed higher level of air pollution than white Americans.

The other interesting thing is that happened, especially for Black Americans, even when you stratified by socioeconomic status.

So in the context of Black Americans, we didn't look at specific question for Hispanic population, and we should, and we will.

But for Black Americans, what we found which was very surprising to me that high socioeconomic status Black Americans breathe higher pollution level than low socioeconomic status white Americans.

So that tells you a lot about the systemic bias and racism.

Why?

Well, what happened is in these marginalized community, there is less pressure and less attention to be in compliance with the different EPA rules.

And we see that systematically.

By the way, there is-- I don't want to speak too much about it.

But there is a different study that we're conducting right now on exposure to air pollution from cryptocurrency data mining, which are not regulated in the United States.

And surprisingly, not surprisingly, where these data mining cryptocurrency are building, where are located, they tend always to be located in the lower socioeconomic status, or in underrepresented minority because it is not the local government, and the pressure of the citizen, and the knowledge to fight back.

SABRINA SHANKMAN: Does historic redlining factor into this?

FRANCESCA DOMINICI: Absolutely, absolutely.

MARC WEISSKOPF: And if I could add related to that, because all of this is absolutely true, but one of the reasons why understanding the mechanisms of this stuff is important is that my suspicion is that at least one part of this is going to be a slightly more generic effect on the brain.

So it will produce inflammation, immune response, things like that are generally-- perturb the brain and have all sorts of effects.

But so do many other things.

So it's not necessarily that air pollution is specifically the thing that causes Alzheimer's disease.

But I think it's giving us a picture into potential mechanisms that get targeted by lots of other stuff.

So on top of minoritized populations often having higher exposures to, say, air pollution, they also, as illustrated by that little clip you showed, have exposures to lots of other things.

And so that can do all sorts of things.

I mean, we just had a talk about the idea that maybe-- and this is one of the things we think, there's something called the blood-brain barrier that is supposed to keep stuff out of the brain.

But you can inflame that.

And you can make that leaky.

And the more you're exposed to all these things, the worse that gets.

So it's not-- it's a double whammy of largely being exposed more to the very things, but also to many things because these are the areas that aren't as regulated.

Or people sort of let industry go.

And then you have all sorts of exposures like that person in the clip.

JOE ALLEN: I think one other thing, just to add to this, and bring it back to Maite's-- the work you're all doing is that there's really been a fundamental shift in the technology.

And it has led to empowerment and citizen science.

So it used to be you'd have an EPA air quality monitor, a handful of them, really, around the country.

We have some sophisticated models.

But we've now put the power in the hands of the community to monitor for themselves and see what's happening.

And that's because relatively new advent of relatively low cost air quality sensors.

They're not scientific instruments.

But you can see pretty quickly, and put it in the hands for what used to be tens of thousands of dollars, now $100 or $200.

And people can measure the air pollution in their home, in their yard, in their community at the micro level.

What's happening outside of my home?

Not relying on some report or other data.

So this is a real big shift, because it's put the power back in the hands of people to say, I can actually see, make the invisible visible.

This is what's happening in my area.

I don't need to see the study.

I can see the monitor.

And I feel it.

And I can see it.

So it's a real shift in terms of the power dynamics of who monitor-- who has the power to monitor.

MARC WEISSKOPF: And also to Maite's point about making that connect-- that you were saying that it was surprising how people weren't connecting, they didn't know about PM 2.5.

Part of it is you don't see it.

It is tiny.

I mean, this is like many times smaller than a human hair.

And so to have a device like this that actually makes it a little bit more visually apparent to you in some way is one of the ways to get a better understanding for it.

MAITE ARCE: And to your point, Joe, putting the power into the hands of community, the community that lives this and breathes this is really important because they are the answer they're able to really speak about their experiences to elected officials, decision makers.

They can really be a powerful support in helping to change what happens in their communities.

SABRINA SHANKMAN: To what extent is there a relationship between citizen science and the work that you all are doing in the more kind of traditional sense of science?

Is there a lot of conversation happening and collaboration?

JOE ALLEN: I'll jump in first.

I think absolutely.

We had a really nice conversation over lunch about the overlapping work.

So my team right now, we're doing a project out in Lahaina related to the wildfires.

And the wildfire's long extinguished.

But the exposure to particles as things get resuspended during the reconstruction is causing continued exposure.

But we're doing it with community partners from there who know the landscape.

Been absolutely devastated in terms of loss of life, loss of property, loss of community.

But they're able to-- they have the monitors.

They have the network.

They're trusted partners.

So there's no way we can ever pull off this kind of work without partners like Maite.

And we're not working with her on that project, but it's very similar.

We'll probably work on other ones after the lunch conversation, I'm sure.

But yeah, that's-- it has to work like that.

MAITE ARCE: And that collaboration is now easier to do because of the tools that are available that are less expensive, and more accessible, and these partnerships as well.

FRANCESCA DOMINICI: Some of my work is-- it's a different flavor.

I will not consider myself in any way someone expert in citizen science as well, although I completely recognize the value and importance.

I think the way that we are trying to do-- to try to inform the local community is to provide interpretable, transparent, and localized information.

So because we analyze an entire national care system, and air pollution data, and claims data for all the continental United States for the last 20 years, instead of just publishing, once again, a research article, is to provide actually easily accessible-- easy to access and localized data.

So then the local community can actually go on the computer and see what's happening in their own census tract, not only what's happening in terms of level of pollution, but also to understand whether or not their community is more at risk for certain diseases than others.

And then that's-- it's really providing an empowering tool.

As well as monitoring and reporting where are-- and we'll talk about that later, where there are the most dangerous, for example, coal-fired power plants, and whether or not they are near their community, or whether there are other industrial facility, they are-- they could have adverse health effect.

And so it's trying to provide the rigorous data.

So then we empower the community to speak.

SABRINA SHANKMAN: So it's like a two-way street?

FRANCESCA DOMINICI: Absolutely.

SABRINA SHANKMAN: You were talking before about how the Clean Air Act has helped kind of eliminate some of the major sources of pollution, or at least mitigate them to some extent.

And the EPA recently approved stronger standards for soot pollution, strengthening the annual health-based national ambient air quality standard for fine particulate matter.

How do you expect that this will impact air quality in the US going forward?

FRANCESCA DOMINICI: Well, it will have a huge impact and a positive impact because that's the law.

And so I mean I think that the revision of the National Ambient Air Quality Standards, for context, the current safety standard for long-term-- for long-term exposure to fine particulate matter is an annual average of 12 micrograms per cubic meter.

And the Biden administration has recently announced that it will be lowered to 9, a national average of 9, so three units, which is a substantial-- it's a substantial act in terms of making it more stringent.

I'm really proud to say that the school, and starting with the Harvard six cities studies, and many of the studies that myself and my colleagues have conducted, have been instrumental in forming that.

The rule is one of the-- I would say, the biggest public health victory in very long time.

So it's going to have a huge effect for the simple fact that by law, the counties-- all the different states will have to submit to the Environmental Protection Agency a state implementation plan.

And they will have to say to tell the Environmental Protection Agency if they're not in compliance with the rule, so if there are not average or some approximation is higher than 9, how are they going to get there?

How they're going to be in compliance.

And so what it means also it means that they will have to look very closely to their inventory, what are all the sources of fine particulate matter, whether it's traffic, where it is industry, whether it's natural gas, coal-fired power plants, and then they will have to say how they're going to-- how they're going to cut that sources to be to be in compliance.

And so lower fine particulate matter, less adverse health effect, and longer life for everybody.

So it's a really good fantastic victory.

SABRINA SHANKMAN: But why 9?

Why is 9?

FRANCESCA DOMINICI: That's a very good question.

So we did-- we did a study in the New England Journal of Medicine that was accelerated to get to form the rule.

And we look at the health benefit when you go from 12 to 10, 12 to 9, 12 to 8.

And so one might ask, well, why not zero?

So I think that zero is nearly impossible because it is always going to be some background level of fine particulate matter.

The evidence that there are thousands of studies all around the world, none of the studies have provided evidence that there is a threshold, or what it means is a lower level of fine particulate matter below which there is no adverse health effect.

So bottom line is, ideally, you want it to get as low as possible, as low as feasible.

In the study that we published, we showed, of course, going from 12 to 8 would be the best, especially for underrepresented minority because in that study, we really want to look at the benefit not only on average for the population, but also look at the benefit for the different underrepresented minority.

They went to 9, which to me, it sounds like they try to be as aggressive as they can, still being feasible.

But there is not-- there is not data to point out that 9 is the magic number, and below 9, there are no adverse health effects.

So it's a compromise between the science and, I would say, the political landscape.

SABRINA SHANKMAN: We love a number that we can hang our hats on.

MARC WEISSKOPF: And well, to that very point, it's slightly problematic.

I mean, so I was on the panel that did-- that came up with this.

And this is-- really, it's all about how the sausage gets made.

So it's a bunch of people around a table.

And there are those arguing for it to be higher.

And there are those like me who are arguing for it to be lower.

And we battle over it.

And they settle on something.

But one of the issues is they-- that panel is not supposed to take economic considerations into account.

So now, somebody else does that at some point.

So that's another thing that plays in.

But to Francesca's point, it is true, the data-- you can go down lower.

And the data sort of-- I personally think, actually, would suggest lower is also very protective.

But weird things happen.

They want a number.

And so when they look at studies, they say, well, what was the mean of the exposure in that study?

And so that study must be speaking to the mean.

And so I spend a lot of time in this panel arguing that there's a lot of great data that's not at the mean.

It's below the mean.

And in fact, if you only had the mean, you don't have any kind of distribution.

So you can't show anything.

And it's things like that we're making arguments.

They actually tended to downgrade Canadian studies because they're not in the US.

But Canada happens to be cleaner.

So they have studies at lower levels.

But some people downgraded them because they're not American.

So it's that kind of process.

MAITE ARCE: I am grateful for the work that you contributed.

The new pollution standards will improve air quality and begin to address the injustices and inequities that have existed historically.

MARC WEISSKOPF: You know, I will say that the WHO's limit is 5.

They suggest 5.

Now surprisingly to me, and I only learned this relatively recently, that Europe is actually worse than us.

Their levels are higher than we have.

But the WHO, which is really supposedly just focused on health, has come down to 5.

JOE ALLEN: Well, we're talking about numbers, so our colleagues here have done amazing work and saved many hundreds of thousands of lives because of this effort to get the National Ambient Air Quality Standards from 12, now down to 9, WHO says 5.

And Francesca pointed out, these are legally enforceable.

That's why they'll work.

Do you know what the legally enforceable particle limit is for indoor air and workers?

Not 12, not 9, not 5, 5,000.

5,000 is the current legally enforceable limit for indoor particles.

There is a major disconnect.

Because outdoor air pollution penetrates inside.

We have indoor sources of particles.

And yet for our workers, the only standards OSHA standard.

It's grossly out of date.

So we're down at 9, 5, 12, this is going to have-- we know it's going to be a massive impact on 12 to 9.

What would it do if we lowered our worker limit from 5,000 to something reasonable, like orders of magnitude lower?

And we have National Ambient Air Quality Standards because of the work of my colleagues over decades.

We don't have a national indoor air quality standard.

So today, we're talking about how does air pollution impact the brain.

I think all of us, first thought is outdoor air pollution.

There's a whole other world of air pollution-- it's indoor air pollution.

And our standards are nothing like what we've done for outdoor air pollution or the successes we've had.

It's a major problem in public health.

And quite honestly, in our regulatory structures how we think about air pollution as just outdoor air pollution.

SABRINA SHANKMAN: Why is that?

JOE ALLEN: OSHA, on its website, says our standards are out of date.

They acknowledge this.

And that's for chemicals and everything else.

We don't spend as much time thinking about the indoor environment, not nearly the amount of resources.

We don't have a study, like Francesca's, millions of people.

A big study in my field, I mentioned 450 people.

It's very different.

We don't-- we don't have these huge cohort studies.

We haven't done this Harvard Six City study follow tens of thousands of people for 10 years.

We haven't done it to the indoor environment.

It's a loose collection of researchers scraping for money, really, trying to do the uplift this research.

But that's-- it's just an-- we don't think about it.

There's a regulatory issue.

Who has regulatory authority over this?

EPA is outdoor.

They have guidance on indoor.

But no real regulatory authority.

So it's really OSHA is the legally enforceable limits for worker protection indoors.

Doesn't count for your home either.

So it's a real problem.

FRANCESCA DOMINICI: So yeah, I mean, thank you, Joe, I think that's a huge issue.

I think that what's the most important thing to do in that context is to identify what are the indoor sources that get to these extremely high elevated PM 2.5.

I mean, and I would say the great majority, if it's low PM 2.5 outside, it's going to be low PM 2.5 inside unless workers are working in a setting where this level of fine particulate matter are really high.

So I think that there is definitely a need-- you don't need to conduct a study like million people.

I think you need to do is to identify sources of indoor pollution that lead to this high level of PM 2.5 indoor, and then regulate.

MARC WEISSKOPF: Well one of the-- I mean, one of the issues is, yes, in the work setting, you can potentially think of regulations through OSHA.

But in your home, you turn on your gas stove, and Joe will tell you, you're going to get a massive spike of particulate matter.

What do we do with that?

JOE ALLEN: If you're cooking, you're stir frying something, you'll get particle levels 100 to 200.

And depending on your ventilation or filtration, it'll linger for hours indoors.

And so you have indoor sources.

You also have outdoor pollution sources.

And even think about what happens with outdoor, let's say it's 12 [INAUDIBLE] meter outside and you're building takes out half of that.

So it's 6 inside.

Your building did a good job.

But you spend 90% of your time indoors.

Most of the outdoor air pollution you breathe happens inside.

Most of the outdoor air pollution you breathe happens inside, even with that reduction happening just because it's the amount of time.

And then-- but we know we can design, to get the solutions, we can design places that actually reduce that 12 to virtually nothing if you have good levels of filtration, good building design.

So we can lower that burden even further.

So you have-- you have the indoor space, I'm biased, this is my topic.

But this is-- but we're talking about air pollution, I think, it's really important to have outdoor air pollution that penetrates inside, we're breathing it, outdoor air pollution inside, plus you're inundated with all these indoor sources.

And then workers can have totally disproportionate impacts depending on whatever they're doing, or the particle levels can be in the thousands of microgram per cubic meter.

SABRINA SHANKMAN: Well, you raise such an interesting point because you can think about things that you can't really regulate out of existence, like wildfires.

But you could potentially regulate, say, a building code to be more protective of people on the inside.

And wildfires is something that I want to talk about because increasingly, that's becoming a big story for us globally across the US and even here in the Boston area, where we're starting to feel the effects of wildfire smoke in a more regular way, including last summer.

So let's talk more about what people can do to protect themselves in situations when the air quality is bad.

And Maite, why don't you talk about that?

Why don't you start out?

MAITE ARCE: I think for communities, the more we can equip them with opportunities to learn about PM 2.5 and how to-- and then help them to also create their own plans for their families and households about what is around them, and what are the practical things they can do indoors

as well as outdoors, like wearing a mask, and staying indoors if there's a wildfire, or there's smoke in the air.

I think also communities want to be part of the solution.

So Francesca mentioned green space and parks.

Communities are planting trees and native plants.

They want that oxygen. And so I think giving-- equipping communities with more information will help them be part of designing what those practical methods to protect themselves are.

SABRINA SHANKMAN: Joe, do you want to talk some more?

JOE ALLEN: Sure, I think we actually-- combine some threads about these low cost sensors and what to do with building and outdoor air pollution.

So when the wildfire blanketed the East Coast, the Canadian wildfires, the skies in New York turned orange.

And so the levels said, I don't know 300, 400, maybe even higher.

In buildings that weren't designed well, have low levels of filtration, we'd see 200 or 100 inside.

That's extremely dangerous.

But in buildings that put in enhanced filtration, the exact kind of filters we're talking about all through COVID, maybe people are familiar with the MERV 13 filter or higher, we saw much level-- lower levels.

So I'll give this building as an example because the wildfire smoke hit Boston first.

Outdoor levels were extremely high in Boston.

Indoor, we kept it below the National Ambient Air Quality Standard because we have upgraded our filters to MERV 13 or 15.

Those capture about 80% or 90% of the particles.

We have the portable air cleaners running here.

And we knew it was successful in real time because we deployed a real-time air quality sensing network in our classrooms. So not only do we say, hey, we think the building is operating correctly.

We can rely on the outdoor air monitors.

We have indoor air quality monitors that said, yeah, our building is performing.

And actually, we could rightly reassure people that the outdoor air pollution is bad, inside our buildings were safe.

Harvard School of Public Health is doing this.

Harvard Business School, we just got the Harvard Health Clinics to put an air quality monitors.

I work with a lot of companies that do this up and down and across the world at this point, actually, to measure indoor air quality and then improve things like filtration, as a protection against wildfire, but also just everyday outdoor air pollution.

FRANCESCA DOMINICI: That's, I mean, it's fantastic.

And I think although it reminds us, once again, of the potential inequity that we see with the consequences of climate change related exposure.

So at Harvard, we're now breathing clean air.

And we have the ability to put expensive filter.

And we know because we are the experts, as well as potentially very, very well off companies.

But what's happening in the communities?

And so we do know that as a result of greenhouse gases and climate change, we're going to have these wildfires becoming more common and more extreme.

And the highly educated and people who are well off will be able to have access and purchase expensive filters.

What are we doing as a science community to disseminate the information and provide the resources of the low income community that we know already right now that are going to be affected?

Are they going to have access to that filters?

And so I think also I have to say that I've been seeing the major tech companies, Amazon, Microsoft, Google, they actually are stepping in to provide-- I mean, classical partnership, why Amazon?

I mean, I'm saying that live, that has all the resources will not cost them too much to deliver and send free filter to the low income community, where we know, we can tell them right now which will be the community that will be affected by the wildfire.

So I think indoor air is important.

It's critically important.

And we can now have the tools to clean the air indoor.

But we need to make accessible to everybody not only to the people that can.

SABRINA SHANKMAN: All right, Amazon, if you're watching, spot.

Just as a warning, we've only got about three minutes left.

But Marc, did you have anything you wanted to weigh in about this?

MARC WEISSKOPF: Well, I want to-- this is sort of touching on another point that I would like to talk about, the business of-- we talked about sources indoors and whatnot.

But this is also true outside.

And so wildfires is an example of one source of PM.

But I think it's important for people to understand that PM, particulate matter 2.5 is simply stuff in the air.

It's whatever of that size.

And depending on whether you're in Boston, or LA, or Phoenix, that's going to be different.

I mean, on the coast, it might have a lot of sea salt in it, for example.

Wildfire is a very specific one.

This is an area that we're not as advanced in, and partly because the models are not so as extensive to be able to say what is actually in that particulate matter.

Because for the brain, it's very important.

I mean, you can have can have a lead element atom stuck to a particle that gets into your brain.

And that lead will do something very specific.

Something else might do something specific.

So knowing where they come from not only helps us understand a little bit potentially about what is really the most toxic factor, but also how to intervene on a public health perspective.

Because it's possible, and a recent paper came out on dementia trying to do this, looking at sources.

And they kind of said-- at least in this paper, I think it's the first.

I'm not going to say this is the final answer, and more needs to be done.

But they sort of targeted-- they said that the wildfire signal and agricultural PM was particularly related to the dementia, subsequent dementia.

So trying to figure out what piece of this, is it traffic?

Is it coal power plants?

Is it wildfires?

Now, wildfires, we can't do much about.

But they're particularly interesting because, I mean, there's massive heat generated there.

All sorts of-- even if it's in the forest, strange things come up, dioxins get produced, things of that sort.

But more and more, these wildfires are actually at the interface between forests and urban areas.

And now you're starting to burn homes and buildings.

And that's producing all sorts of different stuff.

So it's a very different niche depending on where you are.

And part of, I think, where we need to go in the future is to try and pinpoint, does it matter?

Is it any of this stuff?

Or are there particular ones that are particularly relevant?

Because that may tell us where to focus our efforts on the prevention side.

SABRINA SHANKMAN: I'm going to just queue up our last question, rapid fire style because we have one minute left.

If you could change one thing today, to improve air quality, what would it be?

Let's go right down the line.

MAITE ARCE: Expand the number of citizen scientists in the most affected communities.

JOE ALLEN: Nice.

Related to what Francesca was saying, we were trying to change the standards.

The only way it benefits everyone everywhere is if the standards change.

We're changing standards for outdoor air pollution.

We're trying to get the standards to be changed for how we design and operate buildings, such that it's not who can afford a filter, and they're relatively cheap, but it's just, that's the norm.

We shouldn't have unhealthy buildings.

Should just be-- the standard should be healthy buildings, that's how they're designed, and made, and operated.

FRANCESCA DOMINICI: Shut down all the coal-fired power plants.

SABRINA SHANKMAN: All right.

MARC WEISSKOPF: Lower the standard further.

SABRINA SHANKMAN: All right.

There we go.

Well, thank you all so much for this insightful conversation.

I wish we had more time.

But unfortunately, that's it for today.

If you missed any part of the program, you can rewatch it on the YouTube page.

Have a great afternoon.

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