 Let's begin with the lecture for today. Actually I'm saying it L2 but it really should be L2 and L3 because there are two sessions. When we are saying air pollution, one of the things I ask the student is, how do you know there's air pollution? So one of the things that comes up is, it's a perception. So the question is, when did you last look out and say, hey, that's pollution, that's air pollution over there? So either it's visible because it's far away and it could be smoke, it could be dust, it could be smoke coming from the chimney or it could be odor, smell. So for example, if you smell petrol smell, sometimes people like the petrol smell. It's not good, hydrocarbons. Diesel smell or H2S, you know, kip separators, rotten eggs, everybody during some stage in chemistry would have dealt with kip separators. So you know that smell. And leaching powder, sometimes that's smell of chlorine. Sometimes if you're near a swimming pool also, you get the smell. So what is it that we're calling air pollution is pretty much, when we call it air pollution, it is pretty much given by our perception, which is smoke, dust, chimney smoke, which is like a gray scale. When I say gray scale, recently there are some advertisements for fair and lovely where they actually have a scale of different shades of the skin. And what you're supposed to do is, before you start using fair and lovely, you put that on your skin and say, okay, that color matches my skin. And then you two weeks or three weeks, you apply a fair and lovely, and then you come back and then you look again and you say, hmm, the scale is shifted by two steps. It's now fairer. So that's a skin color scale, which fair and lovely have been advertising. It's not a new idea. In air pollution, we've been using it for decades now. You actually don't have a skin color gradation. What you have is a gray scale, all the way from black to white, and sometimes eight shades of gray or sometimes 16 shades of gray. And you take the scale and you put it up against the sky, against the chimney from where smoke is coming. And you say, hmm, this looks like a scale of six, which is darker. Or you can say, hmm, this looks like a scale of two, which is whiter. And the whiter one, more likelihood that it's going to be steam. Whereas the black one would be carbonaceous in nature. So this is before the methods now that we use came in for measuring pollution, et cetera. This is a standard way. But in terms of perception, it still is. When you see it and you say it's black or when you see it's white, you can say there's smoke out there. Just in terms of the color, white and black, white, predominantly, it would be coming from water droplets. Usually, emissions coming out from chimneys at a higher temperature. So when they come out into the cooler air, the steam or the waterway pretends to condense. So you see these white droplets with scatter light, all of light, which is basically why you see white light, like a cloud. Whereas if you're looking at a black smoke, then actually you're seeing it because you're not seeing it. I say it in a funny way, but that's what's actually happening. Black particles in the smoke, the carbonaceous particles, are absorbing all of light. So you see it as black against a clear blue sky or a gray sky. So it's black because you don't see it. But it's carbonaceous because it's absorbing light. OK, so when we say, oh, by the way, if it is not visible and if there's no smell, doesn't mean that it is not polluted. Carbon dioxide doesn't smell. Carbon monoxide doesn't smell. There are many other gases that don't smell. Oxides of nitrogen don't have a little bit of an irritation in the nose if it's at a high concentration. Ammonia definitely has a smell. So you may want to take a look at what are the different gases of concern and what are the ones which could be perceived either through smell or if it is particle matter. Particle matter is what is visible. Gases are not visible. Particles are visible because there's scattered enough light for you to be able to see it. So the perception is, where did you last see pollution? And basically, you would say, I smelt it. Or basically, I saw it. Now against polluted, we want to look at what is clean air? What is it that we call clean air? For us to be able to say, this is dirty air, we have to be able to say, what is clean air? Now this is something which we probably started learning in class 4th and 5th and 6th somewhere, where they just committed it to memory for you that 78% is nitrogen, approximately 21% or so is oxygen, and the remaining 1% are trace gases. Carbon dioxide is about 340 ppm, which is approximately 0.034%. But then I got a little comment after that, which says, which year? That is, now carbon dioxide, by the way, is not a polluting gas. It's not considered a pollutant. It's a part of the natural cycle on Earth. However, it's not considered a pollutant. But we know that the entire health of the planet is getting affected because carbon dioxide is a greenhouse gas, and it actually would influence the radiation balance. So that has been a concern. So when you say 340 ppm or 0.034%, you'd have to say, which year? Because it's changing year by year. And you know that, and I'm sure you probably already have seen this particular graph. I've taken it from Google and look at the massive number of characters over there that are saying what the URL is. Don't worry about this right now. It'll come to you as a soft file, so you can use it later. But the top URL is for a paper, which I think is a 1985 paper. Yes, 1985 paper. You should probably read it. It tells you how the changes in carbon dioxide levels have been going on. This is measured in Hawaii. And so if you look at this graph over here, when I was born, that was 1960, we were in good shape. Earth was in good shape. We were less than 320 ppm. And by the time I graduated, it was already at 340, which is what I have written. See, I've gotten stuck when I graduated. I think I should update my files and actually have it be now around 370. So this is the ever-changing increase, ever-increasing carbon dioxide level. And I think it's an appreciation that students would get by reading the paper and reviewing some of the material that's already a lot of material out there on this. OK? All right. So coming back to what is air pollution, it's given by perception. And if you can't perceive it, it doesn't mean it's not there. Just want to give an example of H2S, hydrogen-sulfide gas, smell of rotten eggs. Apparently, if you can smell it, you're still safe. At some point in time, one of the first things it does, this gas, is attacks the nerve endings in your nose. So at some point in time, if the concentration is high enough, you will not be able to smell it. You're not even able to smell the rotten egg. If it's a rotten egg smell, that means the concentration is low enough for you to be able to detect it. If the concentration goes a little higher, your nerve endings are gone. OK? I think that's all I want to say. I just wanted to let you know. But it's important for students to interact with you on this to look to see where is it that the last saw pollution. So some of you, while coming from home, you probably saw a tum-tum, or you saw a scooter, or you saw a diesel truck, which was emitting a lot of smoke. You could probably have seen the smell, the lovely smell, of paranthas and dosas in the morning in the kitchen. Now, we like that smell, so we don't call it pollutant. But it is actually pollution, right? So it's, I think, important to be able to discuss with students where is it that this is. Chimneys, people see. Oh, there's pollution coming from there. Oh, we don't realize a lot of times that we do a lot of open mass, you know, open burning of waste materials. We just see, you know, in the mornings, people collect garbage in a corner of a street, and then they just light it up. There's smoke. There's uncontrolled emissions over there. OK, so Chula burning, for example, every morning in Chandrapur. And I'll talk a lot about Chandrapur because we've been doing a project over there. You take Chula, and everybody needs to cook. So, you know, they'll take Chula. They'll take coal, which is freely available in Chandrapur. And they will burn the coal by the time it takes about 15, 20 minutes to catch fire. But during those 15, 20 minutes, it is just throwing out smoke. So in the mornings in Chandrapur and the evenings in Chandrapur, you can actually see a thick layer of smoke. Doesn't matter which time of the year, including monsoon time. Typically during monsoon time, you would expect that most of the pollutants, no. Not with smoke. Smoke actually lingers around. And it's not something that goes away like dust during monsoon. So we actually have to therefore let students begin to qualify when they say they see smoke. That's particulate matter. When they smell something, it's probably some gas, whether it's petrol, hydrocarbon, vapor, or whether it is some other gas that they're smelling. Sometimes odor is not defined, especially around municipal waste. One of the hardest things that has been going on is to be able to define odor coming from municipal wastes. So that's just beginning to get a sense of what is air pollution. What is it that you call air pollution? Carbon dioxide is not an air pollutant. However, it does impact the health of the planet. Different scales at which we're dealing with air pollution. So one is local. It can be as local as a kitchen, where there is a stove on which you're cooking. The stove in urban areas usually is gas, LPG. Some places, people who can afford it even have electricity. But by and large, people are using LPG. Most villages, most places where you don't have access to LPG, people would use agricultural byproducts, or coal, or wood. Sometimes they even use cow dung cakes, which is sometimes mixed with rice husk or mixed with coal powder. So the pollution in a room, that's as local as it gets. So once we step out of the house, and let's say if I go to the main gate of my institute or go to a major junction in the city, because so much traffic is over there, while the average air quality in the entire city might be good, but at that place where the police person is standing over there, that person is getting exposed to a lot of pollution. That is as local as it can get in the ambient. Then of course, we can look at an entire region. We can look at an entire Mumbai region, Greater Mumbai region, Delhi region, Greater Delhi region. We can look at a radius of five kilometers, or we can look at a radius of 50 kilometers, depending on how your industry is placed and what kind of an influence it might have on your city. Global, everybody appreciates when you have carbon dioxide. It doesn't matter where carbon dioxide is emitted. It is then getting added to the global atmosphere. So anywhere carbon dioxide will migrate. Particulate matter, a lot of times in Mumbai we have seen that during the daytime, in the middle of the day, suddenly clouds appear or it becomes dusky. And it's really because there was some dust storm in the Middle East or in the African continent. And the winds have actually brought the dust all the way from another continent onto this continent. So that's the level at which it could be operating at a global level. Another aspect, recently some work has been going on in Indonesia and Malaysia, that region, where they do a lot of palm oil and coconut and some other farming. And at the end of the harvesting, they actually just put all of that excess of agricultural byproducts and they just burn it. And the winds have been carrying some of the smoke to Singapore. So Singapore doesn't have a pollution problem, but because another country in the neighborhood is having some agricultural practices which has been going on for centuries, now begins to affect this particular urban area. So we have to be concerned at all levels, at local level, at the region level, as well as at a global level. When it comes down to the scale of vertical, by and large we look at scale as horizontal, x-axis, y-axis at a planar level. But then if you really look at it, we have to look at the vertical level and it's very poetic and we always tend to have this perception that the sky is infinite. It's like there's no end to it. There's a lot of poetry that's been written on it and many songs and Bollywood that actually talk about Neil Gagan and Distance Far Away, et cetera, et cetera. But you know what? It's not that infinite. And just to give a sense of scale, what's written over here is if earth was to be an apple, if earth was to be an apple, then the atmosphere thickness is only as thick as the skin of the apple. So that's it. That's all there is. There's not too much of an infinite over there. It's actually just about 10 to 12 kilometers of actual 80% of the air mass. And beyond that, of course, is the ozone layer, et cetera. So we just got about 10, 12 kilometers in that direction. Also just, I was talking to my son yesterday and I was trying to tell him that there is actually no sky. That sky is an illusion. Like a rainbow, rainbow we know is an illusion. It comes when there's sunshine and some raindrops in the atmosphere. But on a day-to-day basis, we see it every day, the blue, the sky blue, sky. But it's really an illusion. At night, it disappears. There's no sky at night. So what happens actually is that the light from the sun gets scattered by the gas molecules and blue light gets scattered more. So you therefore see it as a sky. Now on days when you don't see a blue sky, it may seem to be cloudy, but a lot of times it is because there is small particles in the air which can be in the form of fog, haze, smoke, dust. These are the ones which prevent sufficient light from the sun to come to you. So you get a sense. You don't see blue skies anymore. You say some kind of a gray sky. So that gray, the blue of the sky gets mixed with scattering coming from these particles. So you end up seeing an illusion now which is more of a gray color than of a blue color. As you go higher up in the altitudes, it gets darker and darker. So a lot of times people, I remember when I was a kid, my mother used to say that you should buy a sky blue color for you. And so I had an association of what sky blue color is. But if you really look at it now, I don't know what sky blue color is because the higher altitudes, the color, the blue color of the sky becomes darker and darker. And of course the moment you go out of the atmosphere is completely black because there's no light being scattered by any more molecules over there. So all of this just to let you know that we have only recently started relating to air as a resource. We have been relating to land, soil, water. We've been relating with these as a resource. But for some reason, because air is just freely available everywhere, we never related with it as a resource. Now more and more colleges are offering courses in not air pollution anymore, not air quality anymore, but in air resource management. So we have started relating with air now as a resource. And I invite you to bring that perspective to the students as well. The third point over here is ambient versus indoor. By and large when we say pollution, you don't ever relate that inside the house, actually it could be polluted. But the air inside is probably only as clean as the air outside. Invariably in the middle of the night, I have to get up in Mumbai on Powai campus and close the windows because there's some foul smell or there's some, not fresh air, let me just say it. That's probably the best way to define it. So you prevent bad air from on a certain part of the day to come in so that you can keep the air inside the room to a certain quality. And then from time to time, you open the window to see if it smells okay outside. Again, a matter of perception doesn't mean that it's still clean, but at least it's not smelling bad. So you open the windows again and you flush out the air. But more importantly, what I wanted to point to over here was ambient air is largely affected by various sources. It could be industry. It could be vehicles. It could be re-entrainment of dust from roads and farms and the desert, et cetera, et cetera. But indoor is in some way closed. It has got to do with cooking. And in the US, of course, there's a lot of work that has been going on also on the VOCs that get emitted from the fresh paint. So I think some years ago, Shah Rukh Khan used to come with an advertisement for a particular paint that doesn't smell like paint. Now, it's another story that when you get into a new car, it smells like a new car. And so you're saying, hmm, that's a new car. And these days you have these air-salt sprays which you can make the car smell like roses or make it smell like vanilla or make it smell like wood. But nowadays they even have a new one which is called new car smell. So you can actually spray the car inside with that smell, it'll smell like a new car. Okay, so ambient versus indoor. Again, indoor, a lot of children and women, especially in Indian rural areas, get affected where they don't have access to LPG. The richest over there might have a kerosene stove. But kerosene also is polluting, you can actually smell it also. Sometimes if it's bad, even the food can smell of kerosene. But otherwise they're using solid fuels. And this whole issue of energy and fuels, it's something that we'll get dealt with in some of the other lectures. So I'm not gonna spend time on that. Our concern over here is from a pollution perspective. So I've written Yale report over there. Yale comes up with this report, I think every other year, I don't remember now. I'll give you the URL for that. But what they do is they actually assess the quality of air in different countries. And recently they published this report and it ranked India somewhere in I think 172 or something out of 200 countries. We were ranked at 172. So this came up in the Lok Sabha and so I got a call from somebody and they said, is this true? Can you please give us some inputs as to whether this is accurate or not? So I along with Dr. Rakesh Kumar and Professor Rashmi Patil, Dr. Rakesh Kumar will be coming as an expert for the expert lecture a little later. He heads the Neere Zonal Lab here in Mumbai. And Professor Rashmi Patil of course she was the founder of our center, one of the founders of our center and she is the authority in air quality work. So in some sense, I'm her student as well. So we consulted and then we said, we give some feedback to Lok Sabha but I just wanna highlight the key things that were of concern over there. It is not that the air pollution in India was really bad as an ambient air quality. In some of the cities, yes it is bad but on an average across India it is not bad but there were two factors that really influenced the index which was being used to measure the pollution. One was the population, the size of the population that was gonna get affected by the pollution and India being, the population density being very high. Of course, large number of people are gonna get affected. And the second factor that affected the index was the use of solid fuels. So the moment you start using solid fuels, whether it is wood or coal or cakes made out of cow dung and some other biomass, we start running into problems. So I'll send you that URL and you're welcome to read it as well as share it with your students. I think it helps when students begin to read some of these and they know that there's a debate in the Lok Sabha about it, their interest in it is then not just academic actually begins, okay, this is how it's being handled or if it's not being handled. Last thing I've written over here is, when I say indoor it is, of course we talked about kitchens but you know, shopping malls are coming up all over the country and these are huge shopping malls and all of them are centrally air conditioned. And earlier there was a concern that the more fresh air you take from outside, you'll have to cool that additional volume of fresh air so the energy cost will go up. So the optimization was done based on minimizing the energy use for cooling. Two other concerns have come up recently. One is if the air outside is more polluted, then you actually need to filter and clean the air before you take a dent at number one. Number two is that wherever there are human beings, there will be carbon dioxide that gets generated as part of your breathing. And this carbon dioxide tends to build up and I'm gonna tell you a little funny story. We did some measurements in some of our classrooms which were centrally air conditioned, closed rooms. We did some carbon dioxide measurements and it turns out that with the class size of anywhere from 250 to 350, the carbon dioxide does build up, okay. And so it could shoot up to as much as 800 ppm or 1100 ppm. And that level of carbon dioxide, we actually did a correlation to see if the number of students who were sleeping in the class actually correlated with the carbon dioxide level and there was a good correlation. So we were then convinced that it was not the boring lecture. It was the carbon dioxide in the air. So that is the question. So you should share that. Okay, now I'd gone to Germany recently, not recently now actually a few years ago and the place where I went to, somebody said that there is a house over there where Einstein used to live. So they said I must go there. And who knows, I might actually breathe in one of the carbon dioxide molecule that Einstein may have breathed out, okay. So it's been many, many decades now since Einstein would have done that. But they said that's possible, you know. So a particular molecule in the air has a certain lifetime. So the whole aspect of balancing out what pollutants we are adding to the atmosphere and how worried we should be about these is going to be determined to some extent by, we know the source term, but we need to have an understanding of the think term. Where would these molecules go? What would be the case of each of these molecules? So there's the capacity of Earth system as a thing. And one of the first things we have to deal with is thermodynamics. If a molecule is so stable that it's going to be there forever and ever, it has no reactivity. Like at some point in time, we thought some of the CFCs, you know, it was the greatest invention of the 60s that it actually didn't react at all. So it could actually be in the atmosphere as a benign molecule for thousands and thousands of years and nothing would happen. However, we didn't realize that the same molecule which had thousands and thousands of years to live could migrate to up to 12 kilometers to the top of the troposphere and go and say hello to the ozone layer. And the moment it got to the ozone layer, ozone was a good reactant for this particular molecule and therefore began to react and cause the ozone hole, which of course we learned and now are beginning to heal that ozone layer. But you know, the life of a molecule, whether if it's carbon dioxide, where does carbon dioxide go? We are hoping that there are more and more trees and enough sunshine that photosynthesis will continue and that carbon dioxide would be taken away. But there's a large sink of carbon dioxide which is in the form of the oceans, okay? So anytime the temperature of the ocean changes, the amount of carbon dioxide in the atmosphere would change because depending on the temperature, the solubility changes, a certain amount of carbon dioxide would either get released or some of it would get added. How it gets added, that mass transfer, et cetera, that's another issue that is more in chemical engineering and proximity. So if you are causing pollution in a city and in a particular location in a city and the city is very far away from the ocean, you can't expect that that CO2 will immediately get taken over by the ocean. Now, there will be a certain length, there will be certain duration for which it hangs around in the atmosphere and it will do the pump that it does while it's in the tank. So the capacity of the earth system as a sink is a big question, continues to be a huge research question. The uncertainties around the fate of, is it going to be eight years before we reach a point of no return or is it going to be 30 years before we reach a point of no return and global warming sometimes, any question is coming from some of these issues which are not resolved. In that capacity we have to deal with characteristic times, what are the kinetics, each of these compounds has its own life cycle, so we don't get into the details of that. However, students should be aware that not all molecules are created equal, each one of them would have a different lifetime, each one have to have a different chemistry in the atmosphere, et cetera, et cetera. The last thing I wanna touch upon is statistics. While you might say the average air quality in Mumbai is good, you cannot say that to the person who's standing, the police person, the traffic police person who's standing in the middle of the heavy junction, traffic junction to say, hey, there's no pollution over here because the average over the entire city is acceptable. Once the system is open, it is not engineered anymore, most of us engineers and scientists control our systems, we control our engineering issues, we always have piped systems and tanks, so we seldom deal with open systems and anytime you're now interacting with nature, dealing with air quality, dealing with water, you actually have to start dealing with open systems, engineered by nature and we do not, no matter what we say, we do not understand very much of how nature works and therefore we need to be able to deal with the open systems in a very different way. Okay, so let's just take a look at what are the learning objectives for today, okay? So I'll be quiet for a moment, why don't you read those two learning objectives and then I'll come back to you. Okay, welcome back. So I just wanna acknowledge something, it takes some effort to come in the mornings for the class and I just want you to know I appreciate your coming and sometimes you get delayed, et cetera, so just please make sure that if you are joining a little later that you actually get a chance to share with some of your other colleagues to see what you may have missed and in any case you have these available on the video but it's important to kind of catch up, otherwise the rest of the day begins to then get lost, okay? So let's begin now. So the objectives for today's learning are, this is for the students, okay? This is for your students. So this is what I would typically do in a class, I'm just sharing with you what I do in a class. So I actually give them the objectives this is what I expect by the time, they should expect that by the time they're done with this class that they would have learned these things. So you'll be able to calculate pollutant concentration related to exposure. And the second objective is, you'll be able to explain effects of meteorology and the physics of dispersion of pollutants in the atmosphere, okay? So those are the two and some of it may not even make sense to the students at this time, that's okay but at least they're beginning to now grapple with this, okay? So the first objective then, when we say pollution is bad, there is a lot of air pollution. How bad is bad, okay? There's got to be some way of saying it. We know what clean air is, but we have to be able to define when I say bad what is bad. So the Central Pollution Control Board has national ambient air quality standards which have two dimensions. One is the concentration of a pollutant so the more concentrated it is, the worse it is for you and for your health. And the other part is, the other dimension is, for how long do you get exposed to it, okay? So if it is at a low level of concentration, I can get exposed to it for a long time and it will still not give you a health effect, but sometimes if it is a very high concentration and you get exposed to it for a short time, then it might affect you. So this is different from the standards that are followed by industry. So for example, when you have occupational safety and aspects there they are looking at if a worker has to go into a factory and deal with something where the pollution level of a particular contaminant may be high, then they have to wear masks and go in, okay? That's different. We're not talking about that. We're talking about ambient air quality, okay? And now recently they've also started talking about indoor air quality, which we will not touch upon here, but ambient air quality is something which is available. And so if the air quality met the CPCB standards, the concentration levels were below that level, then you could say the air is safe to breathe. But if it exceeded a certain number of times in a year, then you would say, hey, this is risky. It's difficult to be now able to assure anybody that the air over is healthy and therefore actions need to be taken to be able to. So when you say how bad is air pollution? How bad is bad? You actually have to have some scale on which you're measuring pollution. And the pollution scale that we're looking at is Central Pollution Control Board has national ambient air quality standards. Against these standards, these are against standards which are based on health, based on some other aspects. These are standards which have been borrowed from some of the other agencies like the United States Environmental Protection Agency and the World Health Organization. So it is a blend of many different standards that are out there. And as an exercise, we give this to the students also to be able to see that not all, so the standards that are being followed in the US may not be the standards that are being followed in India and vice versa, okay? So let's do a class exercise. I say this to the class and students. So I say that the sulfur dioxide, the regulatory limit of sulfur dioxide is 80 micrograms for meter cube as an annual average. So that means that if the concentration was 80 micrograms for meter cube and you were exposed to it 24 hours a day, 365 days in a year, you'd still be okay. As long as it is below 80, you'll be okay. There will not be any health effect. This is for normal human beings. There are people who have issues of asthma and some other diseases. They probably are more sensitive, but this is for normal, healthy human being. So notice that there is another standard. This one is for three hour. So if you were exposed to 1300 micrograms for meter cube for up to three hours, you'd still be okay. You'll still recover from it. That point in time, you might feel a little bad, et cetera. Your skin might, your nose and your mouth might feel a little irritated, but you'll recover from it. So, but if you expose to this level for more than three hours, then it could be detrimental. If it is more than 1300, let's say 1500 for three hours, then again, it is detrimental. So it's a combination of the concentration as well as the duration of exposure. So as an exercise, what I say in the classes, if this is the classroom that you're in and I'm going to ask you to look at the classroom in your remote center, okay. How many grams of sulfur if I were to burn in this classroom would cause a health problem, okay. The question is pretty straightforward. The way we would deal with it is, you actually, the chemistry is simple, okay. Chemistry is not difficult at all. You just say one mole of sulfur combines with one mole of oxygen to give one mole of sulfur dioxide, which means 32 grams of sulfur give 64 grams of, just happens that O2 is also 32. So 32 grams of sulfur would give 64 grams of sulfur dioxide. So which means if you take X grams of sulfur, it would give you two X grams of sulfur dioxide. So that part, the chemistry part in terms of the mass is handled. So when I look at, go back to this slide and it says 1300 micrograms per meter cube. The micrograms part is now already handled by the chemistry. So this 2X should be 1300 micrograms. That part is handled per meter cube. Sorry, when I say 1300, no. 2X is the total mass of sulfur dioxide that's gonna get produced from the sulfur that you burn. The denominator, the volume, is the volume of the room. So mixed in how much volume would lead to exposure concentration limit. So what you're now dealing with is, the actual question is, what is the volume of your classroom in meter cube, okay? So in your room, the X is defined very well. The Y is defined very well. The Z is defined very well. These are well-defined, okay? There's a real ground, actually, the ground that you stand on, the floor that you stand on. That's the XY plane, that is solid, that's firm. There are real walls, okay? Which may not be so in the atmosphere, but that's okay. We're just dealing with it one step at a time. We want to deal with the closed volume for an indoor air quality issue. And we have a real roof. There's no, the ceiling, the sky is open, but here we actually have a roof. So these are well-known. So you know, length, width, and you know the height. So you will know the volume. So now I actually, I'm declaring some prizes. Everybody ready for these prizes? Prizes, prizes, prizes, double dhammaka, okay? So the students will now give their estimate of the volume of the room on a small slip of paper. And then I'll collect these, and then I will do the statistics on it, and then come back next time and give them the prizes. And the prizes are if they are closest, the number, the person, the student, who's closest to the actual will be given a five-star chocolate. And then there is the closest to the average who will be given a chocolate. So this is an exciting exercise. Everybody's now very interested and motivated in actually matching the volume of the room. So, oh, sorry, there's some caution here. The prizes are not coming so easy after all, okay? The caution, and the caution is that this is some experiments in the last few years that we've done, and I just wanna share some of the results from the previous year. Now these are BTEC students, usually in the second year, third year, fourth year. Class size typically anywhere from 200 to 350. The class is being held in a lecture hall like this one. So here are the results for the estimate of the volume of the lecture hall, okay? Whoa. These are the students over here, about 160 of them responded out of the 200. By the way, the Y-axis is log scale, I know it may not be very clearly visible over there, but it is log scale, okay? So one student is saying that the volume of the room is two meters by two meters by two meters. That's eight meter cube. Whereas another student is saying that it is 0.2 kilometers by 0.2 kilometers by 0.2 kilometers, okay? So one, two, three, four, five orders of magnitude, okay? So that is the range. Now if that is going to be the range of the estimate of the volume of the room, the concentration will vary all the way for sulfur to be burned in this room. Remember the question still is how much sulfur can be burned in this room without it having a detrimental health effect on you, okay? So in one case where the volume is smallest, which is that two meter by two meter by two meter room, just burning 20 milligrams of sulfur will cause a panic button to be hit, okay? Which means if you were actually doing these measurements out in the open, in the ambient, you would say, hey, I cannot do any industrial development over here because even the smallest amount of pollutant over here is gonna cause pollution problems and health problems for people. So no industrial development can take place over here. The other extreme is that somebody is saying that you can burn as much as eight kilograms of sulfur and there'll be no problem. So we bring in eight kilograms of sulfur and we burn it in this room and there are people now who are choking and we can only say, okay, we can bring karma for it, okay? Or fate for it. So it's nonsensical because just a simple estimate of a volume of a room can have that kind of a range of 10. Now I'm not saying that most students did that. Maybe only about 10% of the students actually did that. Most of them are in this range. But even here, even here, there's a factor of at least 100, okay? At least a factor of 100 or if not 100, a little, maybe a factor of about 500. So the variation, acceptable variation in the estimate of a room which is well-defined is a factor of 500, okay? That's huge. The implications are that human judgment would get us into trouble. So better measurements, we'll have to deal with this. Or actually the will. Sorry, I didn't mean it will like that. I meant the will to deal with this. You know, students actually don't get up and measure the walls. They don't get up and measure the floor size. They just make an estimate, okay? 30 meters this way, 10 meters this way, five meters this way and they give an estimate. So human judgment is full of flow and therefore it could be in trouble. Even a democratic decision can't be taken. Okay, you can't just take the average of all the 160 respondents because the one which is 100 million or 1,000 million will dominate the average. So you can't use that also. A joke about this is that, you know, if you had to decide democratically what should be the national bird of India, then it will not be the peacock. It will be a crow because the highest population of birds is crow. So, you know, democratic decision like that cannot, the majority doesn't always win. Okay, so this was a fictitious exercise but the atmospheric volume estimation is actually real and we'll get into that in a little bit, okay? So this is your exercise now. This exercise is now being given to all the teachers in this program. Please take three minutes and estimate the volume of your room. Please go ahead. I'm just gonna share a couple of examples of homeworks that we use at the end of this exercise. So just for you to know, these are examples, okay? I'm not expecting you to do these homeworks and submit it as a part of this training. If there is something like that to be done, I'll actually tell you and also tell you the dates by which they need to be submitted. Most probably we'll be doing this after the 10 days. We'll have about two weeks to finish some of the assignments. We don't want to take the time away from the, from the six, eight hours that we have during the day and we appreciate that you would probably have to be traveling back home and there'd be other commitments that you need to take care of. So I got some emails yesterday requesting that we shouldn't be giving any assignment. So you should know that we're not planning on giving you any assignments for homework. If there are any class exercises, then we will do them here. And if there are assignments to be done and there will be, we will deal with that after the 10 days over. We'll give you about two weeks. But we wanna use this 10 days time to be able to share with you some of the work that we do with our students. So I'm gonna share with you, as an example, what are the assignments that we give at the end of this class? So one example or one homework is that I actually have the students go through the websites of Central Pollution Control Board, USEPA, California within USEPA has much more stringent standards. So there's California State Standards, World Health Organization, and Europe has its own standards. So the exercise actually is that they will take all these standards for all the pollutants, the criteria pollutants and compile them in one sheet, which can be printed as a one A4 size paper. So the challenge is actually also to be able to fit all of this information in one sheet. And then, of course, the incentive is that the best compilation will get an ice cream. That's during summer and during winter you can accordingly choose something else. And the other real prize is that the best, and sometimes you may need to make minor corrections and all that stuff, but then once you get the best compilation, you go ahead and make multiple copies and laminate it and then each student can have it as a standard reference. Anytime they want to look at air quality, they have the standard, they don't have to commit to memory, they actually have it in front of them and they can compare different countries and different agencies. So that's one possible homework. This is another homework similar to what we did in class, but slightly different here. You're not actually estimating the volume of the room. There is the volume of the room, but it's actually worked backwards. So the standard is still the same, but this time you talk about an Agrabati stick, okay? An Agrabati stick is assumed, okay? Like at this point in time, there is an assumption that Maggi noodles has lead in it. So we're dealing with that and there are tests that will be carried out to figure out whether that's accurate or not. So somebody has a concern and the concern is that Agrabati might have, I don't know whether it does have or it doesn't have, but Agrabati sticks might have a little bit of sulfur in it. So if there was a three hour, some ceremony going on, some social or cultural or religious ceremony that was going on and Agrabatis are used quite frequently in a closed room and the fans are running so it's fully mixed room. So the contaminant, the sulfur dioxide will get mixed up and be available anywhere in the room. So what is the size of the room, minimum size of the room that's required so that the concentration doesn't exceed 1300 micrograms from meter cube. So that's straightforward, okay? So while we're looking at the learning objective, I think it's important to be able to say what is it that we actually dealt with? So one of the things we dealt with was they actually get familiar with concentrations. What is a concentration? When you say micrograms for meter cube, what is a microgram and what is a meter cube? Is this a gas or is it a particulate matter? If it is particulate matter, then it is the particle mass in the volume of the gas. For gas, it's volume, it's mass of gas in the volume of the gas. So that distinction between gas and particulate matter needs to be made. PPM in, I'm not too happy about using PPM in air quality work. PPM in water works okay because parts per million turns out to be milligrams per liter. It works out well, water having a density of one. But in air, it's difficult to say that because you're not doing volume by volume. If you're doing volume by volume and you say PPM, then you're not too sure whether this PPM is coming from water. So it's a mess. So the best thing to do is to keep micrograms for meter cube for air quality work. By and large, most people are now switching over. They don't use PPM anymore. Although when I showed you the carbon dioxide, I showed you as PPM, okay? So PPM is not very popular now. It's, they usually go for micrograms for meter cube. The time of exposure, we'll send you references for reading. How are they actually saying that this much will be detrimental to your health and less than this will not be detrimental to your health. So there's a lot of literature available also in medical sciences which actually is doing that. So I'll send you some references for that and you can pass them on to your students. Standards, people actually go to the website of CPCB for the first time sometimes and look to see, hey, what is the CPCB, what are the things they do and what are the standards that they are using for India? And of course, the volume calculations could determine the carrying capacity of an air shed and an air shed doesn't have a ceiling. It actually has a false ceiling that keeps changing. So how much pollution, how many pollutants, how much sulfur dioxide, how many agribattis I can burn, how much ha ha ha I can do in this particular place such that my air is still breathable given now that I don't have walls and I don't have a ceiling. So how am I going to determine what is the carrying capacity of this place? Carrying capacity. So by this time, about one hour, 10 minutes into the lecture, the question might come up why are we doing all of this, okay? So why are we doing all of this? Because you, students, okay? Students, this was students. By the way, I invite you to take this on for yourself. In fact, I have an agenda that some of you take this on for yourself because you are accountable for the air quality. Why are we doing this? Why are we doing this? Why are we doing this? Why are we doing this? We're doing this because you are accountable for the quality of air in your city. You are the collector. You need to know what is the status of air pollution as against the CPCV standards. So when you say how bad is bad, you will ask that question as a collector. You will ask that question, hey, how badly is my city polluted, okay? How do you know it is polluted at all? So you will have to go to the CPCV standards and be able to compare the concentrations. Based on that, then you'll be able to say. So as a collector, you will want to know where and how and when is air pollution being measured in your city. So typically, the CPCV has a network of stations which are called National Ambient Monitoring Program, NAMP. National Ambient Monitoring Program, there are some 500 plus stations which are across the country. They measure twice a week, twice a week, a 24-hour average. Okay, twice a week, 24-hour average. So you'll only be able to get an estimate of nighttime, daytime, all put together, how much was the pollution, twice in a week. So it's about 100 measurements in a year, 52 weeks in a year. So about 100 measurements in a year for about 500 locations across India. Each major industry now is expected to have what's called continuous ambient air quality monitoring systems, continuous ambient air quality monitoring systems. This gives monitoring data at an hourly rate, okay? So for example, a power plant, if it is set up over here, then at four corners of its premises, it will be required to have these CAQMSs so that it is ongoingly monitoring the air quality a certain distance away from the plant, okay? That data can be very useful to compare with the twice a week data which is available from NAMP. Now, a lot of times, the data are iffy, okay? The data are not, the quality of the data are not good. So we run into some kind of a problem. And as a collector, you'll have to be concerned about that. So why are we doing all this? If your city is in violation, if your city is not in compliance, we need to identify the key sources of pollution. It's that simple. You need to identify which particular pollutant is exceeding. What is the source of that pollution? Where is it coming from? How much of it is coming? So then accordingly, you can take action. If it is in compliance, if your city is in compliance, then we need to be careful that over the next five years, over the next 10 years, over the next 20 years, that it doesn't reach a point of no return. You still have there for some time to be able to see what is it that you can actually add, but that's gonna get decided, that's gonna get decided by the carrying capacity. One more time it's coming up, the carrying capacity. What is the carrying capacity of your city? Carrying capacity, carrying capacity. Now this is getting a little, so I'm just gonna stop because I think we need some rest. So we'll just rest for a, but in the meantime, let's do something else. Can we do something else? Yes? Okay, let's do something else. Let's take a look, we'll change the channel. So we let's look at some of the homeworks, okay? And let's look at homeworks in a new light. I'm sharing this with you. I'm sharing this because I've tested this out over many, many years now, it has a certain value, and therefore I wanna spend a little bit of time sharing it with you. So this is an example of homework which is given to the students. It's based on study two films, which is I sent the critique handout yesterday by Moodle, and a lot of you had questions about the date on it and whether you need to submit it. No, you don't need to submit it. And this is really for the students, but I just wanna go ahead and get into the details. So as I said yesterday, on a particular date, and it happened to be January 8th this year, Thursday, I gave them this assignment to study this movie. Some of you have even asked for the link for this movie. I'm not too sure whether this is in public domain or not. So I'm not too sure whether I can give you the link, but I'm sure you have enough resources available that students themselves will be able to find these movies and get it for you. So please check with your students, and if you are savvy, you can probably get some of these yourself. Or sometimes you may have to buy it if it's not available somewhere. So this movie, you see this movie, you study this movie on a particular day, and then after that, the next assignment. By the way, I have not talked about global warming at all in these classes before this particular homework. I have not touched upon global warming at all. I've not even dealt with it as an issue. All I'm doing is asking them to see a movie, or study a movie, and then another movie. So this is the second movie. Again, I have not talked about global warming at all. In fact, during my six lectures, I don't talk about global warming at all. Why? Because I think this is something that is out there available and students should be able to do it on their own and grow in the process. So this is the second part of the assignment. This is the third part of the assignment, which is actually the critique. And so this was done on 8th of January. This is done on 12th of January. And after they've seen this on the 12th of January, by 19th of January, they have to submit the written homework. And here is the assignment. The assignment is based on the two films, An Inconvenient Truth and the Great Global Warming Swindle, write a critique. Critique, critique. I mean, my voice goes a little critique when I say that. Critique, okay? Critique with respect to your stand as a student, your stand as a collector, your stand as a young professional, your stand as an adult, your stand as a responsible citizen, okay? Your stand and understanding on the issue of global warming. So there is no right answer to this one. See, most of the time we have trained students to be able to give the right answer, give them a particular concentration of pollution in this room. You know, the worst thing that they'll have to deal with is what's the volume of this room? Okay, but even that is pretty well-defined. But when it comes down to an issue of writing a critique, there is no right answer. It's my personal stand in the matter. And of course, it is informed by the two movies that I've seen because I was not exposed to anything before that, but how much of an influence that those two movies have is going to determine the quality and the content of that particular critique. So a lot of times students don't know what a critique is. So I actually tell them, I give them a dictionary meaning of it, but at the same time, they look up in the dictionary and they sometimes I even ask them to go, I don't know what a critique is. You find out what a critique is. You go to the Google and look for some editorial articles or you look for some scholarly work where actually there are some critiques. So that's that. And then the instructions, okay? For me, this is where the rubber meets the road, so to say. For me, the details of the instructions, that's where God dwells. So God isn't the details, they say. This for me is the test ground. And the first question that comes up for them is, how big should this critique be? So I say, you know, minimum of 1,000 words, they could be more, but it's your stand. But I would say if you wrote at least 1,000 words, that would be acceptable. But anything more than 1,000 words, it's your stand, it's your articulation, so it's up to you. So they have the freedom around that then. The next one is, they'll ask, do you want handwritten or do you want it tight? And invariably what is happening is, they're asking because a lot of submissions, when they do soft submissions, there is a good chance that they may have copied it from someone. It's easy to just copy a soft file, change the font size and change the font and submit it in a different format, and it'll look like a different assignment. I don't have that concern. I absolutely don't have a concern because who I'm dealing with is leaders, who I'm dealing with are responsible citizens, who I'm dealing with people who have honor with. So I don't have a concern that they will copy. So I'm not going to get into that detail. All I'm saying is, whatever works for you. And the thing is, it could be handwritten because some people, like myself, I find it easier to write. When I'm thinking, I prefer to write, I find keyboard a distraction. So if you think better with a pen or a pencil on paper, then do a handwritten one. However, if you think better on keyboard, my son kind of finds that writing is redundant. You know, he's like, why do I even have to write? I mean, I don't even have to know the right spellings because the moment I write even the wrong spelling, you know, Microsoft will correct it for me. Okay, so I don't even have to worry about the right spellings anymore. So, you know, if you think on keyboard, and that's the new generation that is there, then good for you. Then you should do the thinking on the keyboard. I don't want to come in the way of saying that you should handwrite it. Because if they have to copy, they would even copy it. I mean, you know, it's a waste of resource to actually have somebody copy somebody's assignment in handwriting. I mean, they'll get better handwriting or better finger muscles. But you know, in terms of the intellectual development, I don't think it's doing much. Okay, so the caution however is avoid cut and paste. Okay, it tends to suppress your own thought processes. Sometimes it may even help to write it as a letter to a friend. So you may want to encourage them to write it as a letter. Dear Sunil or dear Rathee, I'm writing this letter to you because I have watched these two movies and I'd like to share with you what is the issue of global warming. The two movies are conflicting in nature and I'm still trying to figure out what might be the best way of actually taking a stand. I think I still need to do a little more reading on this. So I'm going to write to you as to what I understand and have it be written as a thousand word letter. So that actually has them open up and start doing the work. So the other part of the instruction is while doing the thinking, identify and include issues and questions that are still unclear for you. So it brings clarity for what you should now be reading for. See, when you start reading, when you start thinking, you'll begin to get a number of questions which you don't have answers to. So it's important to make a note of these questions. You may not be able to answer them in this particular assignment, but if you can document these questions as a part of your assignment, then that is a critique. You've actually listed down the questions which still remain unanswered either for yourself or for the scientists out there and therefore there's work to be done. And of course, the last thing I deal with is that I prefer hard copies of submissions. So the moment I do that, I start getting emails saying that, hey, please save trees, do not use hard copies, but it just works for me. It's more convenient for me. Just from the perspective of logistics. See, 350 students, I have about 10 to 15 students who are helping me as TAs. So just in terms of evaluation of these assignments, et cetera, it works out to me easier to deal with it as hard copies. But you know what? If it works for you to do it as a soft copy, you're welcome to do it. You should do it. Last part is I actually encourage them to discuss, talk, share, argue. All that you need to do with your classmate and others, and yes, you should. But when it comes down to doing the documentation or documenting your thoughts for the assignment submission, please bring honor and do your own work. And I actually tell them, you cannot fail at this. You just can't fail. How can you fail at this? You just can't fail at this, okay? So you gotta do your own work. And most importantly, as you do this assignment, you will find yourself at crossroads. These are young adults. They're just stepping into life. They will find themselves as crossroads. They will not know which is the correct thing to do. What is the stand to take? Inside there is an invitation for an opportunity to grow professionally, okay? So they actually will come to you and they will talk to you because they don't know how to resolve it. And that for me is the first step that they're taking to getting coaching. So key accomplishments of this assignment, okay? So first thing is that some synthesis begins to happen for them. They've studied these two movies and they actually begin to synthesize their thought processes. They begin to deal with abstractions. They begin to take a stand. And I tell them a lot of times that when they go for interviews, when they go for group discussions, this exercise will really help them because they may not talk about global warming in the group discussion. But the moment you begin to develop a muscle for doing critiques, you'll actually be able to take anything that you're doing and be able to bring a critique to it. So when you go for a group discussion, you actually bring the wholesomeness of the particular subject to the table. And you know, people notice that. And of course, without saying it, one of the accomplishments from this assignment is honesty and honor. The space that we have created, as I said in the beginning of the course, beginning of yesterday, was this is a place of honor. This is a place of appreciation. This is a place of a prayer. This is a place of being sacred. So you just never spit in a temple, okay? You will never do that. So for people to know that what you're dealing with is honor and appreciation, they actually do the work that is required of them. They will not do mischief with this. And therefore it reinforces the sacred relationship that we have with the students. Those are some of the key accomplishments from this particular exercise. So for the first time in their adult life, for the first time in their adult life, they're actually being asked to articulate a stand. More importantly, they're doing it in a safe learning environment of your class, okay? So this is the honor we provide for them. I just want to share this with you from the bottom of my heart. This is the honor you provide for them. And it is absolute privilege for us as teachers in doing that, okay? So I just want to leave it at that. I just want you to know that this is just one possible expression of this homework. I invite you to find your own ways to be able to accomplish not just this, but way beyond it, so that by the time they're done with this course with you, they're not the same human being that who, you know, they're not the same human being who entered at the beginning of your class, okay? So this is the opportunity, this is the possibility of this particular course for me through this assignments and through these assignments. Okay, so just a caution, okay? You can't be doing this without some prerequisite and the prerequisite is this. Before giving out this assignment or any such assignment, you must study the two movies yourself. You must write the critique yourself, okay? This is really needed to appreciate the efforts. Okay, I'll tell you, I'll give you an example. This morning, quite a few of you were not here at nine o'clock, okay? Quite a few of you were not here at nine o'clock. And I was noticing if I was not living on campus, if I was living even two kilometers away from the campus, what is the world I would have to deal with so that I can be here on time and it is not the same as what I deal with on campus? So you should know that I totally have appreciation of what it takes for you to come from your home to the center. Now why I know this is because actually I have gone through the exercise of living outside the campus and coming here on time for the class. So till such time as you don't do this assignment yourself, you would not have an appreciation of what are the things that the students are going through. So please do this exercise yourself before you give this assignment. On a scale of one to 10 of difficulty, this assignment is 20. It is a very, very difficult assignment. Therefore, you need to do it first. Okay, all right, thank you very much. Now, so let's just go to one of the centers here. Achinai, DMI College of Engineering. Good morning, sir. The program is going well, very nicely. Very interesting. So I have a question for you. Yes, sir. Are you the collector of your city? Yes. Okay, absolutely. So please keep listening from the perspective of if you were responsible for the air quality of your city, what is it that you should be learning? What is it that you should be teaching the students? Okay, so thank you very much, DMI College. I'm going on to the next college now. All right, this is now Bengal Engineering College's Havla. Bengal Engineering College, how are you? How are you, Shiklan? All right, very good. How's it going? One of you please share with me, what are you learning? Yes, sir, very good morning, sir. Good morning. We're enjoying the course. Hello, sir. Yes, are you learning? Yeah, yeah, we are learning. We are all enjoying the course. Okay, are you collector of Havla? No, supposed to be. Yes, you're supposed to be. I just want you to get that nobody will call you collector, but you should know you are the collector. I may not be the administrative collector, but regarding environmental. Thank you, yeah. Thank you very much for taking that on. And you know, you really want to encourage your students to be able to taking responsibility for the air quality in their city. I think that's the game to be played. That's the context. Thank you, sir. Okay, thank you very much. Go ahead for tea now. Bye-bye, everybody, go have a cup of tea. I'll meet you at 11 o'clock. Thank you.