(highlight:: Air Pollution as a Major Global Health Risk
Transcript:
Speaker 1
Well, air pollution is the single largest environmental and occupation risk factor to public health globally. But the global burden of disease estimates, it accounts for something like 6.67 million deaths a year. This was as of 2019, which to give context is about 12% of all deaths globally.)
- Time 0:03:51
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(highlight:: Air Pollution is a Cocktail of Particulate Matter That Can Harm All Parts of the Huma Body
Transcript:
Speaker 1
So the thing about air pollution, which makes it so harmful in particular particulate matter air pollution is that particulate matter is not a single substance, right? It's it's it's it's a cocktail of various things that are in the air. They just happen to be finer than 2.5 microns in diameter, which is a tiny fraction of how thick your hair is. And it is composed of a variety of chemical substances, some of which are relatively harmless, some of which are extremely toxic. So it could be stuff like soil dust, which is sort of naturally occurring or sea salt, which are likely to be, you know, not particularly harmful. And then it's stuff like lead and other heavy metals that are that are suspended in in the air. There are inorganic compounds like sulphates and nitrates, which sort of originate from vehicular emissions, from coal, power plant emissions and so on. So it's a variety of different things because these particles are as fine as they are, they're able to enter the enter the lungs, enter the systemic circulation. And basically these various things that that there have no business being in our body can sort of travel to different organs and cause a variety of different harms.)
- Time 0:04:47
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(highlight:: Frustrating Examples of Air Pollution: Burning Municipal Waste & Companies Dumping Flu Gas
Transcript:
Speaker 2
What is perhaps the most outrageous or emotionally grabbing example of air pollution to you? So something that the thing that I have in mind is something that barely benefits the person who's emitting all of this pollution. But it's causing massive health damage to people to people in the nearby area.
Speaker 1
One thing that comes to mind is sort of municipal waste burning that happens in, you know, sort of many cities in the global south. So basically this is waste that gets collected from people's homes and instead of sort of being transported to a waste management facility or a landfill or something basically gets Burned at some point because that's like the fastest way to dispose of it, which really sort of points to poor delivery of public services. But this is like ubiquitous in virtually every small or even like medium-sized city. It happens in larger cities too in this part of the world. So I think that's something that sort of truly annoys me because it feels like the kind of thing that ought to be fairly easily managed. But it happens a lot. It happens because people presumably don't think that it's particularly harmful. I don't think it saves a ton of money for the municipal corporations and other local government that I'm meant to sort of manage it. So that's one example that comes to mind. I find it particularly annoying simply because it happens so often it's something that you're able to smell in so many different parts of these cities. Another which seems sort of downright evil to me is a whole bunch of industries that tend to not use the pollution control equipment that they have in their facilities already. And just basically dump the flu gas as it's called, the gas that gets emitted from the various processes in the industry without the emission controls in the middle of the night. It can't be detected as easily as it would in the day. And this is basically to save what I suspect is change in terms of maintenance and operation costs of this equipment. You have the equipment and there are these standards. So that's I think downright evil on sort of the part of these industries.)
- Time 0:08:10
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(highlight:: Understanding the Constituents and Effects of Air Pollution
Summary:
Air pollution comprises organic compounds, trace heavy metals like lead, and particles finer than 2.5 microns.
The damage caused by air pollution leads to various health issues, especially heart and lung diseases, resulting in mortality and ill health.
Transcript:
Speaker 1
The other constituents of it are there are a bunch of what are called organic compounds, which again get emitted from a variety of different sources. There are trace heavy metals, which are particularly harmful. So this could be lead, for example, being emitted from, for example, the improper smelting or disposal of lead acid batteries and so on. So yeah, so it's a wide variety of different things, which just happened to be finer than 2.5 microns. And I mean, just to sort of, I think, help get a sense of this, a micron or a micrometer is a millionth of a centimeter and therefore like something like a tenth of the thickness of your hair, If that helps.
Speaker 2
So let's let's when we come back and analyze a little bit more carefully how large is the scale of the damage being done by by air pollution. Because I guess on this show, we don't just settle for something really bad. We want to kind of quantify it a little bit more more specifically. Yeah. So so far we've talked about the issue that it causes people to die. So because a whole bunch of mortality. What are the different ways in which it causes people to die or suffer like directly ill health.
Speaker 1
So the evidence is strongest when it comes to a bunch of heart and lung diseases, right?)
- Time 0:15:02
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(highlight:: Specific Health Impacts of Air Pollution: Disease & Neonatal Deaths
Transcript:
Speaker 2
So let's let's when we come back and analyze a little bit more carefully how large is the scale of the damage being done by by air pollution. Because I guess on this show, we don't just settle for something really bad. We want to kind of quantify it a little bit more more specifically. Yeah. So so far we've talked about the issue that it causes people to die. So because a whole bunch of mortality. What are the different ways in which it causes people to die or suffer like directly ill health.
Speaker 1
So the evidence is strongest when it comes to a bunch of heart and lung diseases, right? So some of the the principal sources of death and illness that can be attributable to air pollution seem to be heart disease, lung cancer, something called chronic obstructive pulmonary Disease, which is basically like a chronic lung infection, which you know, once you have it, it doesn't go away. It cannot be reversed. Right. There are lower respiratory infections like pneumonia, strokes, type two diabetes. So I think those are some of the the big health harms. So global burden of disease, I'm sure your listeners are familiar with it. But but just in case this is an effort that's sort of anchored by by the IHME, the Institute for Health, Metrics and Evaluation. I think that's right. That's it. Yeah. So so basically these are sort of periodic massive scientific enterprises that they basically bring together sort of the who's who of public health researchers to try and synthesize Evidence on on a bunch of different risk factors. So that's what they do for air pollution as well. It tends to be a relatively sort of conservative effort in that they do try and restrict to the the sources of illness and death, where the evidence is relatively stronger. Although they are pretty transparent that there are significant uncertainties involved in these estimates. Right. So till 2017, right? So which is like two iterations back. The air pollution harms were basically restricted to just five diseases. And the ones that I mentioned earlier, heart disease, lung cancer, COPD, lower respiratory infections and strokes. They have since added type two diabetes and one of the more, I guess like an emotional one with which tend, which tends to get a lot of attention when these reports get released is they Also included impacts on neonatal deaths in GVD 2019. Right. So this is basically infants that die within the first, I think, 27 days after their birth because of the exposure of the fetus within the womb to to air pollution. And they estimated something like half a million neonatal deaths per year that might be attributable to air pollution, which, you know, again, is like a striking number. So basically these are infants that, you know, are likely born preterm or possibly with lower birth weight than the night, and as a result, as sort of more vulnerable and and and and therefore Is a higher chance of of death within the first month. Yeah, which again, I think is a is a striking and if true alarming number.)
- Time 0:15:48
- air pollution, public health, global burden of disease,

(highlight:: The Dose Curve of Air Pollution: Marginal Health Impact Decreases as Size of Dose Increases
Transcript:
Speaker 1
The shape of what's called the dose response curve. So basically, the dose of your pollution exposure and therefore the response in terms of your health impacts seems to be curvilinear. So basically, at lower levels of pollution, a marginal increase leads to a higher increase in relative risks than at higher levels of air pollution. So basically, the relative risks sort of flatten out as the pollution increases. So beyond the point, if I could swear, you're basically screwed. It doesn't matter if you're, yeah, so that seems to be the shape of the relative risks,)
- Time 0:20:54
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(highlight:: Problematic Assumptions: Air Pollution is Not Necessarily Better Outside of Cities
Transcript:
Speaker 1
Yeah, so I think one that is actually a significant sort of hindrance to effective policy in India and similar countries is that air pollution is assumed to be an urban problem. This was certainly true in, you know, sort of big industrial cities and so on, where sort of evolution started becoming sort of visible and salient. So I think of London or Pittsburgh, Los Angeles. So in places like India, though, that's just not true because rural air pollution can be significant. In fact, it's on average rural exposure is not very different from urban exposure. One of the largest sources of air pollution exposure in India, in Pakistan, a whole bunch of other countries would actually be the household burning of solid fuels, wood, dung cakes And things like that. And yeah, so it's actually not at all an urban issue alone. And historically, it has been treated as that. So, for example, there are no rural air quality monitors in India and it's sort of a chicken and egg thing. So, till recently, the question, the response to why there aren't there aren't monitors there was that look, we know villages are clean. That's where you go when you have respiratory problems and so on. And so, so yeah, it neither gets sort of measured because it's assumed to be not a problem and because there isn't any measurement to suggest otherwise that never really gets updated.)
- Time 0:37:03
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(highlight:: Air Pollution Can Vary Greatly, Depending on Weather and Climate
Transcript:
Speaker 1
Weather and climate play a huge role in terms of both variations over the course of the day, variations from one day to the next. And potentially, if there are cities which have significant micro-climates, it's very likely that it'll also translate into sort of spatial heterogeneity in air pollution.)
- Time 0:50:17
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(highlight:: London is a Leader in Utilizing Sensors To Monitor Air Pollution Geographic Variation
Transcript:
Speaker 1
I think London in many ways has been something of a leader on this. The density of the low cost sensors that London has is extremely unusual, and it's sort of becoming a bit of a model for other cities to sort of replicate when it comes to thinking about How one monitors evolution. So traditionally, you basically had a few monitors, but these very sophisticated, expensive monitors in a few sort of carefully selected locations. But since we've learned that they can actually be the kind of variation from one neighborhood to another, from one road to another, and so on, and that might actually be a reasonable Thing to target the sources of that local variation, even in order to make a larger impact on the quality in the city. There has been a growing sort of call for how do you integrate things like low cost sensors, which didn't exist even like 10 years back. In a sense, we weren't sure about the quality of the data that they produce. We have made significant progress in the last decade or so, and we have a reasonable handle on their strengths and limitations. So, yeah, so there's this call to have hybrid monitoring networks sort of complement the more expensive stuff with just a very large number of low cost sensors, try and measure this Variation.)
- Time 0:52:14
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(highlight:: Common Sources of Air Pollution
Transcript:
Speaker 1
From among the 20th century sources, there are things like waste burning, which we sort of briefly touched upon earlier, widely prevalent practice. So, so there's this waste burning, there is road dust, for example, which is basically roads being poorly maintained and as sort of vehicles go over it, it sort of breaks down a little Bit and it actually adds up to quite a quite a significant fraction. And then there are the sort of more sort of standard sources that folks would be familiar with, things like vehicles, industries, power plants that sort of burn fossil fuels results In greenhouse gases but also leads to a bunch of different pollutants, which then sort of react in the atmosphere, eventually forming a lot of other gases that are coming from the atmosphere, So particularly it matter as a class, right, can get directly emitted from from some sources construction dust road dust from, you know, to some extent combustion, but it also is something That gets formed in the atmosphere because other gases that have been emitted react and and that are less than 2.5 microns.)
- Time 1:01:53
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(highlight:: Air Pollution is Comprised of Numerous Small Sources, Which Makes It Harder to Solve
Transcript:
Speaker 1
The contributions of different sources for a city like Delhi, waste burning, vehicular emissions, industrial and power plant emissions, and a variety of residential and commercial Sources mainly the preparation of food, right. All of these are, you know, give or take sort of 20% plus or minus 5%. And as classes, they're sort of roughly similar to each other. Now, each of these are actually fairly broad categories like among industries you have, you know, power plants and another large, formal sort of manufacturing plants and things like That. But then there are also a variety of sort of smaller enterprises in formal industries, like, you know, the battery recycling type things or evase recycling. Again, these things can add up to quite a bit. So, so that multiple individual sources that are part of these larger classes with vehicles, for example, again, you do you have some sub categories like trucks, which might, you know, There are small number of vehicles on the road, but can have disproportionately large contributions, while the number of like cars and two wheelers might actually be much smaller Relative contributors. So, yeah, so for a city like Delhi, you almost have this sort of equalish split between these four, five broad categories of sources at a national level. There seems to be evidence that suggests that that household burning is the single largest source accounting for something between 25 to 30% in terms of the ambient equality exposure. This, by the way, is separate from the impact it has indoors, and we can come back to this point later. About 10 percentage each is from industries and power plants, and then you have smaller and smaller share. So at a national level, vehicular emissions actually might potentially be in the single digits, and you have industrial and residential sort of actually accounting for the vast majority.
Speaker 2
Yeah, so I guess an unfortunate bottom line from that is that there's not there's no one thing that if we just targeted that, that would really solve the issue. Unfortunately, it's spread somewhat evenly across quite a lot of different sources. So in order to make big progress and reduce their pollution by half or two thirds or four fifths, you're going to have to deal with like five different five different categories in a pretty Big way.
Speaker 1
Exactly. And that's one of the things that also makes the evolution in developing countries hard and also sort of different from evolution, as was sort of seen in the US or UK in the first half the 20th century, right, where it was primarily dominated by industrial pollution and to some extent, the use of coal for heating. They're just like a much wider variety of sources, which sort of fall under different sort of government agencies, which operate at different scales, and therefore making progress Becomes harder to do. And you would have to make progress on each of these sources because they all contribute enough.)
- Time 1:03:17
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(highlight:: History of Industrial Emissions Regulation: Chimney Stack Height -> Pollutant Concentratio
Transcript:
Speaker 1
So with with industrial emissions, typically the way regulation functions is that all of these industries that pollute have chimney stacks. From where the the the flue gas and the other pollutants escape for the longest time across the world, regulation was basically about like the height of the chimney stack. So the assumption was that you make that tall enough and the impacts are not sort of felt in the immediate vicinity, which is not untrue except that the pollution can travel and and over Time, all of this adds up. So, so, so, so the next generation of regulation in many ways was to set standards for what the concentrations of pollutants in these chimneys could be. So there is a mechanism by which the pollutants are measured in the chimney use sort of compare it with what the regulatory standard ought to be. So in order to comply with these standards, the industry is basically install a bunch of pollution control equipment, scrubbers and filters and things called cyclones and so on, which Are meant to sort of clean up the air and regulators basically measure this from time to time. If you're found to be above the standards that have sort of been given to you, there is some form of, you know, sort of punitive action.)
- Time 1:18:48
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(highlight:: A Reduced Complexity Model For Air Pollution Based On Evidence-Based Acid Rain Policy
Transcript:
Speaker 1
So, so I made a grant to this sort of consortium of primarily sort of academic partners to develop something called a reduced complexity model. Right. So, so let me try and explain what this is and why I'm sort of excited about it. One of the challenges with sort of policy analysis on figuring out what kinds of interventions will work well and so on is that. Translating a particular action to sort of the delta in emissions from that particular source is relatively straightforward. Right. But going further and saying that this action, which will have this delta of emissions from this source will result in this improvement in concentrations, right, which is what we care About most is significantly harder to do because depending on the source that the pollutants may disperse to like various scales, they may react with various other substances in the Atmosphere. So capturing this dynamic requires a very specific form of expertise that allows you to model dispersion on the one hand, but also atmospheric chemistry. So it requires a specific kind of expertise. It requires enormous computing power and time. So if you're basically consider, for example, coal power plants, right. So you're looking at potential alternative policy interventions that you could take. So there is a particular kind of emissions control technology that is going to get mandated. Alternatively, you're saying that you're going to tighten the standards by X percent and everybody has to comply it with it in whatever way they want. Alternatively, you're saying these power plants have to be shut down. Right. Now, trying to figure out what impact each of these alternative scenarios would have on like air quality levels actually becomes pretty sort of complicated. Yeah. From like a scientific standpoint. Right. And that has meant that the folks who do policy analysis are folks who also have the ability to like make, you know, sort of do the scenario modeling and and so forth. Now, I'd submit that the vast number of people who have the atmospheric chemistry expertise. Don't really have any kind of expertise on like understanding policy. I see. Right. Right. And then the folks who can do like the policy stuff and like understand the nuances of how these things cost and have no ability to like do the atmospheric chemistry stuff, which which Creates a gap in like the policy analysis that gets produced, which creates this particular gap that we have in like not having any cost benefit analysis. Or not nearly enough cost benefit analysis of different policy actions. What the reduced complexity models will do back to the grant is basically simplifying that sort of second step of the process. Right. So essentially they make some approximations on like the atmospheric chemistry site, but basically provide this very nifty computationally light tool that you can learn. So folks who don't have the atmospheric chemistry training and so on can just use the tool, generate the scenarios they want, be able to figure out what impact it will have at like a fraction Of the costs, a tiny tiny fraction of the time involved. And that potentially helps create the foundation for like new quantitative policy analysis on alternative interventions.
Speaker 2
Right. Which makes me like super excited about the grant. Yeah. But I can talk about the case against it. Sure. Yeah. Okay. So, so in a nutshell, this would allow someone who's say an expert on transportation or on, you know, house fuel burning, who's not a climate scientist to actually add a reasonably accurate Level, a tolerably accurate level model. What implications this would have across the, across the air shed if policy and emissions, like pollution emissions would change in this way or that. And I guess this would allow them to say a whole lot more and potentially to communicate to politicians and the public, like what benefits they might expect to see if they changed change Policy in some direction. That seems, seems pretty good. What's the case against it.
Speaker 1
So the case against it is that, I mean, this is field building from like an even earlier stage than with like some of the other work right on the governance support type stuff. In some sense, we are creating or trying to create the supply of policy analysis, assuming that there is either a latent demand or the demand will get created once this stuff is out there And is seen as credible and. Interesting or insightful, which is a non-trivial assumption. Yeah, yeah. I think you would, you could justifiably say, look, we are starting at a fairly low base. There are probably a bunch of actions that, that you could do without any of this very particular kind of policy analysis and given the way, given the way politics works and given the Way sort of policies get decided and implemented and so forth. There is enough sort of messiness in there that this kind of thing might not actually add a tremendous amount of value and you might end up doing the same stuff. So I think that's a perfectly legitimate point. Yeah.
Speaker 2
Why is it worth it anyway?
Speaker 1
Why I support it is that if you look at air quality governance in other countries, right? The way the US EPA works, the way something called the CLRTAP, which is the Convention of Long Range Transboundary Air Pollution, which was basically this surprisingly successful International convention, which involved, you know, when it was signed, the Soviet Union, the US, Canada and most of the European countries in trying to solve acid rain. Initially, and then actually go ahead and try and tackle other types of evolution. The way these things function, you know, had analysis of this kind almost at its core. So there were, there was sort of diplomatic engagement and compromises and reconciliation, all of that happening with the CLRTAP. But in many ways, the policy analysis and scientific assessments sort of provided like the facts, if you will, of, you know, like that sort of informed the contours of those negotiations. Right. Likewise with the US EPA, I'm sure there are a ton of political negotiations, but the cost benefit analysis is like almost by default. When states drop their implementation plans, they like running some of these models that look at like alternative policy scenarios and so on. That's that happens as process. Right. So there is good reason to believe that this adds value helps sort of becomes the foundation of evidence based sort of governance and policy making of a particular kind that has basically)
- Time 2:37:44
- policymaking, air pollution, policy analysis,

(highlight:: Air Pollution as a Major Global Health Risk
Transcript:
Speaker 1
Well, air pollution is the single largest environmental and occupation risk factor to public health globally. But the global burden of disease estimates, it accounts for something like 6.67 million deaths a year. This was as of 2019, which to give context is about 12% of all deaths globally.)
- Time 0:03:51
-

(highlight:: Air Pollution is a Cocktail of Particulate Matter That Can Harm All Parts of the Huma Body
Transcript:
Speaker 1
So the thing about air pollution, which makes it so harmful in particular particulate matter air pollution is that particulate matter is not a single substance, right? It's it's it's it's a cocktail of various things that are in the air. They just happen to be finer than 2.5 microns in diameter, which is a tiny fraction of how thick your hair is. And it is composed of a variety of chemical substances, some of which are relatively harmless, some of which are extremely toxic. So it could be stuff like soil dust, which is sort of naturally occurring or sea salt, which are likely to be, you know, not particularly harmful. And then it's stuff like lead and other heavy metals that are that are suspended in in the air. There are inorganic compounds like sulphates and nitrates, which sort of originate from vehicular emissions, from coal, power plant emissions and so on. So it's a variety of different things because these particles are as fine as they are, they're able to enter the enter the lungs, enter the systemic circulation. And basically these various things that that there have no business being in our body can sort of travel to different organs and cause a variety of different harms.)
- Time 0:04:47
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(highlight:: Frustrating Examples of Air Pollution: Burning Municipal Waste & Companies Dumping Flu Gas
Transcript:
Speaker 2
What is perhaps the most outrageous or emotionally grabbing example of air pollution to you? So something that the thing that I have in mind is something that barely benefits the person who's emitting all of this pollution. But it's causing massive health damage to people to people in the nearby area.
Speaker 1
One thing that comes to mind is sort of municipal waste burning that happens in, you know, sort of many cities in the global south. So basically this is waste that gets collected from people's homes and instead of sort of being transported to a waste management facility or a landfill or something basically gets Burned at some point because that's like the fastest way to dispose of it, which really sort of points to poor delivery of public services. But this is like ubiquitous in virtually every small or even like medium-sized city. It happens in larger cities too in this part of the world. So I think that's something that sort of truly annoys me because it feels like the kind of thing that ought to be fairly easily managed. But it happens a lot. It happens because people presumably don't think that it's particularly harmful. I don't think it saves a ton of money for the municipal corporations and other local government that I'm meant to sort of manage it. So that's one example that comes to mind. I find it particularly annoying simply because it happens so often it's something that you're able to smell in so many different parts of these cities. Another which seems sort of downright evil to me is a whole bunch of industries that tend to not use the pollution control equipment that they have in their facilities already. And just basically dump the flu gas as it's called, the gas that gets emitted from the various processes in the industry without the emission controls in the middle of the night. It can't be detected as easily as it would in the day. And this is basically to save what I suspect is change in terms of maintenance and operation costs of this equipment. You have the equipment and there are these standards. So that's I think downright evil on sort of the part of these industries.)
- Time 0:08:10
-

(highlight:: Understanding the Constituents and Effects of Air Pollution
Summary:
Air pollution comprises organic compounds, trace heavy metals like lead, and particles finer than 2.5 microns.
The damage caused by air pollution leads to various health issues, especially heart and lung diseases, resulting in mortality and ill health.
Transcript:
Speaker 1
The other constituents of it are there are a bunch of what are called organic compounds, which again get emitted from a variety of different sources. There are trace heavy metals, which are particularly harmful. So this could be lead, for example, being emitted from, for example, the improper smelting or disposal of lead acid batteries and so on. So yeah, so it's a wide variety of different things, which just happened to be finer than 2.5 microns. And I mean, just to sort of, I think, help get a sense of this, a micron or a micrometer is a millionth of a centimeter and therefore like something like a tenth of the thickness of your hair, If that helps.
Speaker 2
So let's let's when we come back and analyze a little bit more carefully how large is the scale of the damage being done by by air pollution. Because I guess on this show, we don't just settle for something really bad. We want to kind of quantify it a little bit more more specifically. Yeah. So so far we've talked about the issue that it causes people to die. So because a whole bunch of mortality. What are the different ways in which it causes people to die or suffer like directly ill health.
Speaker 1
So the evidence is strongest when it comes to a bunch of heart and lung diseases, right?)
- Time 0:15:02
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(highlight:: Specific Health Impacts of Air Pollution: Disease & Neonatal Deaths
Transcript:
Speaker 2
So let's let's when we come back and analyze a little bit more carefully how large is the scale of the damage being done by by air pollution. Because I guess on this show, we don't just settle for something really bad. We want to kind of quantify it a little bit more more specifically. Yeah. So so far we've talked about the issue that it causes people to die. So because a whole bunch of mortality. What are the different ways in which it causes people to die or suffer like directly ill health.
Speaker 1
So the evidence is strongest when it comes to a bunch of heart and lung diseases, right? So some of the the principal sources of death and illness that can be attributable to air pollution seem to be heart disease, lung cancer, something called chronic obstructive pulmonary Disease, which is basically like a chronic lung infection, which you know, once you have it, it doesn't go away. It cannot be reversed. Right. There are lower respiratory infections like pneumonia, strokes, type two diabetes. So I think those are some of the the big health harms. So global burden of disease, I'm sure your listeners are familiar with it. But but just in case this is an effort that's sort of anchored by by the IHME, the Institute for Health, Metrics and Evaluation. I think that's right. That's it. Yeah. So so basically these are sort of periodic massive scientific enterprises that they basically bring together sort of the who's who of public health researchers to try and synthesize Evidence on on a bunch of different risk factors. So that's what they do for air pollution as well. It tends to be a relatively sort of conservative effort in that they do try and restrict to the the sources of illness and death, where the evidence is relatively stronger. Although they are pretty transparent that there are significant uncertainties involved in these estimates. Right. So till 2017, right? So which is like two iterations back. The air pollution harms were basically restricted to just five diseases. And the ones that I mentioned earlier, heart disease, lung cancer, COPD, lower respiratory infections and strokes. They have since added type two diabetes and one of the more, I guess like an emotional one with which tend, which tends to get a lot of attention when these reports get released is they Also included impacts on neonatal deaths in GVD 2019. Right. So this is basically infants that die within the first, I think, 27 days after their birth because of the exposure of the fetus within the womb to to air pollution. And they estimated something like half a million neonatal deaths per year that might be attributable to air pollution, which, you know, again, is like a striking number. So basically these are infants that, you know, are likely born preterm or possibly with lower birth weight than the night, and as a result, as sort of more vulnerable and and and and therefore Is a higher chance of of death within the first month. Yeah, which again, I think is a is a striking and if true alarming number.)
- Time 0:15:48
- air pollution, public health, global burden of disease,

(highlight:: The Dose Curve of Air Pollution: Marginal Health Impact Decreases as Size of Dose Increases
Transcript:
Speaker 1
The shape of what's called the dose response curve. So basically, the dose of your pollution exposure and therefore the response in terms of your health impacts seems to be curvilinear. So basically, at lower levels of pollution, a marginal increase leads to a higher increase in relative risks than at higher levels of air pollution. So basically, the relative risks sort of flatten out as the pollution increases. So beyond the point, if I could swear, you're basically screwed. It doesn't matter if you're, yeah, so that seems to be the shape of the relative risks,)
- Time 0:20:54
-

(highlight:: Problematic Assumptions: Air Pollution is Not Necessarily Better Outside of Cities
Transcript:
Speaker 1
Yeah, so I think one that is actually a significant sort of hindrance to effective policy in India and similar countries is that air pollution is assumed to be an urban problem. This was certainly true in, you know, sort of big industrial cities and so on, where sort of evolution started becoming sort of visible and salient. So I think of London or Pittsburgh, Los Angeles. So in places like India, though, that's just not true because rural air pollution can be significant. In fact, it's on average rural exposure is not very different from urban exposure. One of the largest sources of air pollution exposure in India, in Pakistan, a whole bunch of other countries would actually be the household burning of solid fuels, wood, dung cakes And things like that. And yeah, so it's actually not at all an urban issue alone. And historically, it has been treated as that. So, for example, there are no rural air quality monitors in India and it's sort of a chicken and egg thing. So, till recently, the question, the response to why there aren't there aren't monitors there was that look, we know villages are clean. That's where you go when you have respiratory problems and so on. And so, so yeah, it neither gets sort of measured because it's assumed to be not a problem and because there isn't any measurement to suggest otherwise that never really gets updated.)
- Time 0:37:03
-

(highlight:: Air Pollution Can Vary Greatly, Depending on Weather and Climate
Transcript:
Speaker 1
Weather and climate play a huge role in terms of both variations over the course of the day, variations from one day to the next. And potentially, if there are cities which have significant micro-climates, it's very likely that it'll also translate into sort of spatial heterogeneity in air pollution.)
- Time 0:50:17
-

(highlight:: London is a Leader in Utilizing Sensors To Monitor Air Pollution Geographic Variation
Transcript:
Speaker 1
I think London in many ways has been something of a leader on this. The density of the low cost sensors that London has is extremely unusual, and it's sort of becoming a bit of a model for other cities to sort of replicate when it comes to thinking about How one monitors evolution. So traditionally, you basically had a few monitors, but these very sophisticated, expensive monitors in a few sort of carefully selected locations. But since we've learned that they can actually be the kind of variation from one neighborhood to another, from one road to another, and so on, and that might actually be a reasonable Thing to target the sources of that local variation, even in order to make a larger impact on the quality in the city. There has been a growing sort of call for how do you integrate things like low cost sensors, which didn't exist even like 10 years back. In a sense, we weren't sure about the quality of the data that they produce. We have made significant progress in the last decade or so, and we have a reasonable handle on their strengths and limitations. So, yeah, so there's this call to have hybrid monitoring networks sort of complement the more expensive stuff with just a very large number of low cost sensors, try and measure this Variation.)
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(highlight:: Common Sources of Air Pollution
Transcript:
Speaker 1
From among the 20th century sources, there are things like waste burning, which we sort of briefly touched upon earlier, widely prevalent practice. So, so there's this waste burning, there is road dust, for example, which is basically roads being poorly maintained and as sort of vehicles go over it, it sort of breaks down a little Bit and it actually adds up to quite a quite a significant fraction. And then there are the sort of more sort of standard sources that folks would be familiar with, things like vehicles, industries, power plants that sort of burn fossil fuels results In greenhouse gases but also leads to a bunch of different pollutants, which then sort of react in the atmosphere, eventually forming a lot of other gases that are coming from the atmosphere, So particularly it matter as a class, right, can get directly emitted from from some sources construction dust road dust from, you know, to some extent combustion, but it also is something That gets formed in the atmosphere because other gases that have been emitted react and and that are less than 2.5 microns.)
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(highlight:: Air Pollution is Comprised of Numerous Small Sources, Which Makes It Harder to Solve
Transcript:
Speaker 1
The contributions of different sources for a city like Delhi, waste burning, vehicular emissions, industrial and power plant emissions, and a variety of residential and commercial Sources mainly the preparation of food, right. All of these are, you know, give or take sort of 20% plus or minus 5%. And as classes, they're sort of roughly similar to each other. Now, each of these are actually fairly broad categories like among industries you have, you know, power plants and another large, formal sort of manufacturing plants and things like That. But then there are also a variety of sort of smaller enterprises in formal industries, like, you know, the battery recycling type things or evase recycling. Again, these things can add up to quite a bit. So, so that multiple individual sources that are part of these larger classes with vehicles, for example, again, you do you have some sub categories like trucks, which might, you know, There are small number of vehicles on the road, but can have disproportionately large contributions, while the number of like cars and two wheelers might actually be much smaller Relative contributors. So, yeah, so for a city like Delhi, you almost have this sort of equalish split between these four, five broad categories of sources at a national level. There seems to be evidence that suggests that that household burning is the single largest source accounting for something between 25 to 30% in terms of the ambient equality exposure. This, by the way, is separate from the impact it has indoors, and we can come back to this point later. About 10 percentage each is from industries and power plants, and then you have smaller and smaller share. So at a national level, vehicular emissions actually might potentially be in the single digits, and you have industrial and residential sort of actually accounting for the vast majority.
Speaker 2
Yeah, so I guess an unfortunate bottom line from that is that there's not there's no one thing that if we just targeted that, that would really solve the issue. Unfortunately, it's spread somewhat evenly across quite a lot of different sources. So in order to make big progress and reduce their pollution by half or two thirds or four fifths, you're going to have to deal with like five different five different categories in a pretty Big way.
Speaker 1
Exactly. And that's one of the things that also makes the evolution in developing countries hard and also sort of different from evolution, as was sort of seen in the US or UK in the first half the 20th century, right, where it was primarily dominated by industrial pollution and to some extent, the use of coal for heating. They're just like a much wider variety of sources, which sort of fall under different sort of government agencies, which operate at different scales, and therefore making progress Becomes harder to do. And you would have to make progress on each of these sources because they all contribute enough.)
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(highlight:: History of Industrial Emissions Regulation: Chimney Stack Height -> Pollutant Concentratio
Transcript:
Speaker 1
So with with industrial emissions, typically the way regulation functions is that all of these industries that pollute have chimney stacks. From where the the the flue gas and the other pollutants escape for the longest time across the world, regulation was basically about like the height of the chimney stack. So the assumption was that you make that tall enough and the impacts are not sort of felt in the immediate vicinity, which is not untrue except that the pollution can travel and and over Time, all of this adds up. So, so, so, so the next generation of regulation in many ways was to set standards for what the concentrations of pollutants in these chimneys could be. So there is a mechanism by which the pollutants are measured in the chimney use sort of compare it with what the regulatory standard ought to be. So in order to comply with these standards, the industry is basically install a bunch of pollution control equipment, scrubbers and filters and things called cyclones and so on, which Are meant to sort of clean up the air and regulators basically measure this from time to time. If you're found to be above the standards that have sort of been given to you, there is some form of, you know, sort of punitive action.)
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(highlight:: A Reduced Complexity Model For Air Pollution Based On Evidence-Based Acid Rain Policy
Transcript:
Speaker 1
So, so I made a grant to this sort of consortium of primarily sort of academic partners to develop something called a reduced complexity model. Right. So, so let me try and explain what this is and why I'm sort of excited about it. One of the challenges with sort of policy analysis on figuring out what kinds of interventions will work well and so on is that. Translating a particular action to sort of the delta in emissions from that particular source is relatively straightforward. Right. But going further and saying that this action, which will have this delta of emissions from this source will result in this improvement in concentrations, right, which is what we care About most is significantly harder to do because depending on the source that the pollutants may disperse to like various scales, they may react with various other substances in the Atmosphere. So capturing this dynamic requires a very specific form of expertise that allows you to model dispersion on the one hand, but also atmospheric chemistry. So it requires a specific kind of expertise. It requires enormous computing power and time. So if you're basically consider, for example, coal power plants, right. So you're looking at potential alternative policy interventions that you could take. So there is a particular kind of emissions control technology that is going to get mandated. Alternatively, you're saying that you're going to tighten the standards by X percent and everybody has to comply it with it in whatever way they want. Alternatively, you're saying these power plants have to be shut down. Right. Now, trying to figure out what impact each of these alternative scenarios would have on like air quality levels actually becomes pretty sort of complicated. Yeah. From like a scientific standpoint. Right. And that has meant that the folks who do policy analysis are folks who also have the ability to like make, you know, sort of do the scenario modeling and and so forth. Now, I'd submit that the vast number of people who have the atmospheric chemistry expertise. Don't really have any kind of expertise on like understanding policy. I see. Right. Right. And then the folks who can do like the policy stuff and like understand the nuances of how these things cost and have no ability to like do the atmospheric chemistry stuff, which which Creates a gap in like the policy analysis that gets produced, which creates this particular gap that we have in like not having any cost benefit analysis. Or not nearly enough cost benefit analysis of different policy actions. What the reduced complexity models will do back to the grant is basically simplifying that sort of second step of the process. Right. So essentially they make some approximations on like the atmospheric chemistry site, but basically provide this very nifty computationally light tool that you can learn. So folks who don't have the atmospheric chemistry training and so on can just use the tool, generate the scenarios they want, be able to figure out what impact it will have at like a fraction Of the costs, a tiny tiny fraction of the time involved. And that potentially helps create the foundation for like new quantitative policy analysis on alternative interventions.
Speaker 2
Right. Which makes me like super excited about the grant. Yeah. But I can talk about the case against it. Sure. Yeah. Okay. So, so in a nutshell, this would allow someone who's say an expert on transportation or on, you know, house fuel burning, who's not a climate scientist to actually add a reasonably accurate Level, a tolerably accurate level model. What implications this would have across the, across the air shed if policy and emissions, like pollution emissions would change in this way or that. And I guess this would allow them to say a whole lot more and potentially to communicate to politicians and the public, like what benefits they might expect to see if they changed change Policy in some direction. That seems, seems pretty good. What's the case against it.
Speaker 1
So the case against it is that, I mean, this is field building from like an even earlier stage than with like some of the other work right on the governance support type stuff. In some sense, we are creating or trying to create the supply of policy analysis, assuming that there is either a latent demand or the demand will get created once this stuff is out there And is seen as credible and. Interesting or insightful, which is a non-trivial assumption. Yeah, yeah. I think you would, you could justifiably say, look, we are starting at a fairly low base. There are probably a bunch of actions that, that you could do without any of this very particular kind of policy analysis and given the way, given the way politics works and given the Way sort of policies get decided and implemented and so forth. There is enough sort of messiness in there that this kind of thing might not actually add a tremendous amount of value and you might end up doing the same stuff. So I think that's a perfectly legitimate point. Yeah.
Speaker 2
Why is it worth it anyway?
Speaker 1
Why I support it is that if you look at air quality governance in other countries, right? The way the US EPA works, the way something called the CLRTAP, which is the Convention of Long Range Transboundary Air Pollution, which was basically this surprisingly successful International convention, which involved, you know, when it was signed, the Soviet Union, the US, Canada and most of the European countries in trying to solve acid rain. Initially, and then actually go ahead and try and tackle other types of evolution. The way these things function, you know, had analysis of this kind almost at its core. So there were, there was sort of diplomatic engagement and compromises and reconciliation, all of that happening with the CLRTAP. But in many ways, the policy analysis and scientific assessments sort of provided like the facts, if you will, of, you know, like that sort of informed the contours of those negotiations. Right. Likewise with the US EPA, I'm sure there are a ton of political negotiations, but the cost benefit analysis is like almost by default. When states drop their implementation plans, they like running some of these models that look at like alternative policy scenarios and so on. That's that happens as process. Right. So there is good reason to believe that this adds value helps sort of becomes the foundation of evidence based sort of governance and policy making of a particular kind that has basically)
- Time 2:37:44
- policymaking, air pollution, policy analysis,