Air pollution is really bad
Let’s invest in better understanding its impact in order to save lives.
Air pollution is really bad. Median estimates put the number of people killed by ambient air pollution annually at 7 million, on par with obesity and tobacco. “It also represents a major global annual economic impact of $5 trillion” (Juginovic et. al).
The worst kind of air pollution is PM2.5, some of the smallest particles. These predominantly come from fossil fuel emissions, as well as industrial applications and burning solid fuels indoors.
Developing countries tend to have higher levels of PM2.5 air pollution, and thus bear a heavier burden of the illness and death toll, along with the accompanying economic hit.
Most developed countries had much higher levels of air pollution in the past, but have implemented interventions including air quality standards and effective enforcement of air quality legislation. While local air quality can still be above recommended limits in some developed-country locations, on the whole it is much better than air quality in regions like South Asia and Sub-Saharan Africa.
Unlike issues like obesity and tobacco, there is very little that individuals can do about their personal exposure to polluted air. Addressing air pollution requires targeted policy interventions. One way to support targeted policy interventions is by gathering an abundance of data on air quality.
Air quality measurement has, until recently, mostly been done through costly ($150k+) monitoring stations and fuzzy satellite imagery analysis. However, new low-cost devices like the PurpleAir monitor ($250 each) can give us more confidence in our estimates of local air quality for much cheaper.
Low-cost air quality monitors (AQMs) have, to the best of my knowledge, not been the focus of any organized air quality intervention. I claim that funding a network of low-cost AQMs in South Asia and Sub-Saharan Africa would be a high-impact intervention for effective altruists.
Epistemic status: quite confident in most of the research into the harms of air pollution, different countries’ approaches, and the likely biggest challenges ahead for those interested in addressing air pollution. The idea about funding a network of air quality monitors in South Asia and Sub-Saharan Africa is much less certain; at this point, it’s still in its infancy.
I recently traveled to India for three weeks. My most important lasting takeaways all have to do with the diversity of cultures and languages, the monuments and natural treasures, and of course the food. But, coming from an American context, one facet of life in India that caught me off-guard was the air quality. I would have worn an N95 mask outside in Mumbai and Delhi, even if that wasn’t required. From across Back Bay, we couldn’t see the Mumbai skyline less than a mile away - and this on a not-especially-bad day! I noticed air quality issues even high in the mountains of southern India, and in locations far from any major city. Within a couple days of being in India, I could feel the effect that the poor air quality had on my lungs and my physical stamina. It made me wonder how ordinary Indian citizens put up with it, and what India might look like with cleaner air.
India might be one of the worst offenders, but it has company at the bottom - China’s air quality is improving but still quite poor, for instance, and parts of Sub-Saharan Africa are highly impacted by air pollution as well. And while air quality has generally been getting better in the developed world, over half the world’s population lives in an area with worsening air quality. This causes millions of premature deaths annually and costs trillions of dollars’ worth of economic losses. Improving global air quality, and mitigating its more harmful effects, seem like extremely cost-effective potential areas of intervention.
One important precondition for effectively addressing air pollution is having a thorough understanding of the problem. Until recently, this required expensive monitoring equipment, or fuzzy analysis of satellite images. But low-cost air quality monitors could completely change the landscape of what we know about air pollution.
To that end, I propose a possibly transformative intervention: building out a network of low-cost air quality monitors in South Asia and Sub-Saharan Africa. Each monitor requires just $250, electricity, wireless internet capability, and a willing host. Currently, there are fewer than 100 low-cost AQMs connected to the PurpleAir network in both regions combined. Increasing that number by an order of magnitude to 1000 AQMs, by my back-of-the-envelope math, would cost less than $1 million. If people were interested, they could sponsor an AQM in one of these regions, perhaps organized through a grant program. This would be a powerful source of data on air quality and could be used both by individuals to protect their health and by policymakers to target their air quality interventions.
What follows is a brief investigation of air pollution. I’ve organized it around the questions I had about the subject - first, about the scale of the problem, and then about what potential interventions exist and whether they are cost-effective. This is, again, a shallow investigation; I haven’t looked through all these studies with a fine-toothed comb. The preponderance of evidence all seems to move in the same direction, though, which is worth taking seriously. One important addition to this proposal would be a more detailed cost-effectiveness analysis for deploying a network of low-cost AQMs throughout South Asia and Sub-Saharan Africa; I suspect this to be a highly effective intervention, but it’s worth a closer look.
Air Pollution: Key Background
Where does air pollution come from?
Air pollution comes mainly from burning fossil fuels, but also from industrial and agricultural processes. When we talk about air pollution, we’re often referring specifically to particulate matter (PM), bits of airborne matter less than 10 micrometers wide. That’s less than a human red blood cell. As epidemiologists have learned recently, the most insidious air pollution consists of smaller-yet particles: PM2.5, matter less than 2.5 micrometers wide, one-twentieth of the width of a human hair. (WHO). PM2.5 pollution is responsible for over 4 million deaths annually, according to the Global Burden of Disease study, and is the cause of ~90% of ambient pollution-related deaths.
In addition to trace elements, most PM2.5 (79-85%, per Bell et. al) consists of sulfate, nitrate, ammonium, elemental carbon, organic carbon, silicon, and sodium ion molecules. To take a couple examples, ammonium pollution comes from vehicle emissions, sulfate pollution comes from power plants, metals processing and smelting facilities, and vehicles, and of course carbon emissions come from burning fossil fuels. We can say with confidence that burning fossil fuels creates a huge proportion of the observed PM2.5 in the atmosphere, and that in the absence of such activity, we would likely see lower PM2.5 concentrations.
Ozone is also an important component of air pollution, correlated with other sources of PM2.5. (Ozone pollution is really important, but not the focus of this investigation.)
How many people a year die from air pollution?
Estimates range from ~3 million to ~9 million premature deaths due to air pollution globally, on an annual basis. The WHO and IHME estimate, respectively, 7 million and 6.7 million annual global deaths.
UChicago’s Air Quality Life Index estimates that the average person in the world loses 2.2 years of life expectancy to air pollution.
Of the many million people killed globally by air pollution annually, about 1 million of those are in Africa. Traditionally, the concern with air pollution in Africa has been about indoor burning of solid fuels. More than half of all African air pollution deaths are attributed to burning fuels like wood, animal dung, and crop waste for cooking indoors. However, an increasing share of African air pollution deaths are attributed to ambient PM2.5 air pollution (Fisher et. al, 2021).
What is the mechanism connecting air pollution to early death?
“PM2.5 (particles less than 2.5 micrometers in diameter) can penetrate deeply into the lung, irritate and corrode the alveolar wall, and consequently impair lung function” (Xing et. al). Nearly as many people die of ambient air pollution annually as tobacco, for much the same reason - toxic materials are breathed in, then travel to the lungs, where then cause damage to the walls of the lungs.
“Exposure to such particles can affect both your lungs and your heart. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:
premature death in people with heart or lung disease
nonfatal heart attacks
decreased lung function
increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing” (EPA).
Why is it worse in developing countries?
The stylized answer to this question is that developed countries and developing countries have different cost-benefit analyses when it comes to the tradeoffs of burning fossil fuels. In the US, where the average standard of living is quite high, there is more demand for clean air, a more robust policy including strict air quality standards, and more bulletproof enforcement of clean air policy. For developing countries, the value proposition seems to be that burning cheap fossil fuels in an attempt to develop and thereby raise general standards of living outweighs concerns about air quality and health. This might be especially true in the poorest countries, where diseases that developed countries have eradicated or can treat easily are much higher causes of premature death, and where thereby air pollution is further downgraded as a source of concern.
Indoor vs. outdoor is an important distinction. Household air pollution is often a product of cooking. Many Sub-Saharan African countries rely solely on solid fuels (coal, charcoal, wood, agricultural residue, animal dung, and kerosene, among others) to cook, and the resulting air pollution is often contained indoors in higher concentrations for longer periods of time than ambient outdoor PM2.5.
There is some correlation between lower economic development and higher levels of PM2.5 pollution, but it’s not perfect. Regional effects are important here, since PM2.5 pollution isn’t always confined to its country of origin but can disperse to other countries in the region depending on wind patterns.
It’s not just developing countries! “In 2018, 73.6% of the EU urban population was exposed to excessive concentrations of particulate matter of diameter less than 2.5 microns (PM2.5) which is considered the fifth leading mortality risk factor” (Juginovic et. al). So even in developed countries, PM2.5 is still a major problem.
Is air pollution getting better or worse?
“Despite efforts to reduce air pollution in many countries there are regions, notably Central and Southern Asia and Sub-Saharan Africa, in which populations continue to be exposed to increasing levels of air pollution” (Shaddick et. al, 2020). In essence, pollution isn’t on an inexorable downward trend, and in fact much of the world might see higher PM2.5 in the near-term future. Sub-Saharan Africa is a really challenging case, because a lot of their ambient air pollution sources (eg. dust instead of fossil fuel emissions) are not as easily controllable through policy levers.
In short: it seems like air pollution is getting worse in precisely the places where it’s already worst, Sub-Saharan Africa and South Asia. (China is an outlier here, in that it had until recently the world’s worst air quality but has been making significant improvements in the past decade.)
How do we measure air pollution?
Traditional on-the-ground air quality monitors (AQMs) continuously sample the ambient air, testing the makeup of samples. They are the scientific “gold standard,” and they are what we use to calibrate low-cost AQMs. The catch: they’re very expensive, with the low end traditional AQM starting around $15,000, ranging up to $150,000. This cost is an important limitation, especially for developing countries.
Satellite imaging techniques are one, newer way of measuring air quality. There are benefits here - in places we don’t have on-the-ground measurement, using satellite imaging is very helpful! However, there is more noise in this data than in data obtained from on-the-ground air quality monitors.
Low-cost AQMs: “Inside a PurpleAir sensor shines a laser beam, which illuminates particulate matter floating in the air, a technique known as light scattering. Think of it like shining a flashlight through the desert—you’ll see all kinds of dust particles moving about. “The intensity of the reflection will give you an idea of the size of the particle, and then the number of reflections gives you an idea of the number of particles,” says Dybwad” (WIRED). These sensors cost $250 each. They have to be calibrated for the local area, but they are an increasingly important tool for measuring PM2.5 concentrations.
How many DALYs/QALYs are added per unit of air pollution abated?
One disability-adjusted life year (DALY) is “the equivalent of one year of full health.” Similarly, one quality-adjusted life year (QALY) is “the academic standard for measuring how well all different kinds of medical treatments lengthen and/or improve patients’ lives.” These measures are more informative than a simple lives-saved calculation, although they have their limitations: “QALYs can lack sensitivity and may be difficult to apply to chronic disease and preventative treatment…Similarly, standard life expectancy figures may overestimate DALYs saved when actual (local) life expectancy is shorter.”
As we might expect, air pollution results in the loss of a significant chunk of DALYs/QALYs. “Altogether, air pollution was linked to seven million deaths globally and in excess of 100 million disability-adjusted life years (DALYs) annually. It also represents a major global annual economic impact of $5 trillion” (Juginovic et. al)."
One study suggests that reducing PM2.5 by 1 μg/m3 in England and Wales would “yield more than…540,000 QALYs [quality-adjusted life years]…to adults aged 40 and above over their remaining lifetime.” This intervention would be worth over 34 billion GBP (Schmitt).
An especially concerning study, Heft-Neal et. al (2018), measured the effects of PM2.5 concentration on infant mortality in Sub-Saharan Africa. “They find that a 10μg/m³ increase in PM2.5 concentration is associated with a 9% rise in infant mortality. This suggests that PM2.5 exposure is responsible for 22% of infant deaths in the studied countries; this means 449,000 infant deaths in 2015 alone.” This implies that a significant chunk of the DALYs/QALYs lost to air pollution take the form of infant mortality, an especially cruel wrinkle.
What have developed countries done to abate air pollution?
For this section, I looked into what one developed country, the United States, has done. My limited understanding is that European policy is different in the details but similar in structure. Of course, developing countries will have different cost-benefit analyses.
The EPA says: “Our central benefits estimate exceeds costs by a factor of more than 30 to one.” “In 2020, the Clean Air Act Amendments will prevent over 230,000 early deaths. Most of the economic benefits (about 85 percent) are attributable to reductions in premature mortality associated with reductions in ambient particulate matter” (EPA).
How does the Clean Air Act work? Regarding PM2.5, the EPA sets and enforces the air quality standard. Right now, the “primary annual PM2.5 standard to 12 micrograms per cubic meter (µg/m3) and retaining the 24-hour fine particle standard of 35 µg/m3.” This is higher than the WHO’s recommended standards of 5 µg/m3 annually and 15 µg/m3 for a 24-hour period. The current standards were unchanged, controversially, under Trump, but they are currently under study and likely to be revised downward. The national actual levels of PM2.5 pollution are below that standard:
“State plans also must control emissions that drift across state lines and harm air quality in downwind states. Congress designed the law to minimize pollution increases from growing numbers of motor vehicles, and from new or expanded stationary sources (i.e., power plants, industrial plants, and other facilities that are not mobile)” (EPA).
Enforcement: “The 1990 Amendments required all major pollution sources and certain others to apply for and operate pursuant to operating permits that assure compliance with all of their Clean Air Act requirements…EPA finds violations using information‐gathering authorities that allow EPA to inspect facilities, to require monitoring or testing of emissions or to demand the production of documents…EPA is authorized to assess administrative penalties of up to $37,500 per day of violation, up to a maximum amount of $290,000…” (EPA).
One especially interesting enforcement provision in the Clean Air Act is the citizen lawsuit. “As enacted in 1970, the Act empowered citizens to enforce its provisions by bringing suit in federal court if and when the EPA procrastinated or defaulted in prosecuting violations.” The legal provision allowing citizens to bring suit to enforce Clean Air Act provisions is a powerful tool to keep the federal government accountable.
Could developed-nation policy work in developing countries?
One potential strategy would be to update air quality monitoring and standards in Sub-Saharan African countries via legislation, as the US did. However, many countries lack relevant, strong and autonomous regulatory bodies, making this intervention challenging - I would guess it’s risky in the hits-based giving sense.
Development history cuts both ways in this conversation. Western countries underwent long periods of sustained high levels of particulate concentration during the early periods of their development - London in the early 19th century is the iconic example. And developing countries today including China and India have rapidly increased their emissions and resulting air pollution in the past three decades. So even as global emissions decline or remain steady in the developed world, as developing countries catch up the global rate of emissions has remained on a steady upward trajectory.
There are reasons to think that newly developing countries, like most in Sub-Saharan Africa, might be able to avoid the worst of these air quality effects associated with development. For one thing, energy tech development is already undercutting fossil fuels in price in many developed-world contexts. It is by no means a foregone conclusion, but it’s possible that as that technology improves and becomes more widely available, Sub-Saharan African countries will be able to scale their power supplies without relying as much on fossil fuels.
Much of the region is well-suited to solar power, in particular. The IMF predicts that over half of Africa’s power generation will be solar by 2100. The Brookings Institution notes, however, that “fossil fuels and biomass will play an increasingly important role by 2050, but, ultimately, both conventional energy sources will decline and be dwarfed by a diverse array of renewable energy sources dominated by solar.” Targeted policy interventions could help the region transition to more reliance on renewables and less on fossil fuels more quickly, reducing the potential impact of development on air quality.
Air Pollution: Possibility for Effective Intervention
Is air pollution neglected?
There has recently been lots of academic study about air pollution, but perhaps not until very recently a widespread understanding of the scale of air pollution’s harms. Maybe that causes it to be underrated in policy conversations, even if correctly weighted in academic contexts.
Vox: “In 2018, a team of earth scientists at Duke and Columbia universities modeled what would happen to air pollution deaths if the world actually acted to confront climate change. They considered a scenario where 180 fewer gigatons of CO2 are emitted by 2100. That’s roughly the reductions needed to keep warming to 2ºC or below — the goal of the Paris climate agreement. If we reduce emissions that much, we would prevent about 110 million to 196 million premature deaths by 2100. Averaged over the 80-year period the paper considers, that’s 1.4 million to 2.5 million deaths per year averted.”
In a paper aptly titled “Implementing the US air quality standard for PM2.5 worldwide can prevent millions of premature deaths per year,” Giannadaki et. al estimate that implementing US air quality standards would reduce premature deaths due to PM2.5 by “69% in China, 49 % in India and 36 % in Pakistan,” among other locales. However, they caution that “desert dust and wild fires…to date represent a challenge to public health in the countries in and around the dust belt. For these countries it will not be possible to meet the US and EU standards.” (The dust belt is “an area that extends from North Africa across the Middle East and South Asia to East Asia.”)
One analysis “indicates that in 2019, air pollution cost Indian business a staggering $95 billion due to reduced productivity, work absences and premature deaths…3% of GDP” (Dalberg).
Is it tractable?
Could we throw money or political will at reducing PM2.5 concentrations in developing countries? Or is their trajectory determined by the cost-benefit analysis of the good that burning fossil fuels does to help developing countries develop?
Air pollution is different from peer diseases like tobacco-related deaths and obesity-related deaths since there is no real argument that individuals have any control over their exposure to ambient air pollution. Of course, tobacco and obesity-related illness and death are informed by a whole host of social and regulatory factors, but there is a meaningful way in which individuals’ choices relate to their incidence and severity of these outcomes. This is decidedly not the case with air pollution. This makes it harder to give individuals advice about what to do to reduce their own incidence of air quality-related disease (“Move to rural Colorado” is bad advice, as is “stop driving”), but perhaps easier to have a big impact using policy levers, since they don’t rely on individuals changing behavior.
Vox: “Since 2013, China has reduced air pollution by 29 percent, for an average lifespan extension of 1.5 years for each of its citizens (assuming there’s no backsliding on pollution).”
The good news about air quality interventions is that improvement doesn’t rely on meeting a threshold - the benefits of reducing pollution seem to be pretty linear, in that a small reduction in pollution is proportional to a small reduction in harmful impact.
How do we actually mitigate PM2.5 exposure?
The best answer for developing countries seems to be: develop. That’s the path that the US and Europe took to mitigating air pollution. The concern here, as mentioned, is the political economy: especially for India and China, they seem to have made the calculation that the energy produced by burning coal is worth the air quality issues. With some targeted interventions, though, it’s possible we could see Sub-Saharan Africa avoid the same fate.
The EPA is working with megacities in Sub-Saharan Africa: “EPA’s Megacities Partnership assists targeted countries as they develop air quality management plans.” Essentially, they are advising cities (currently just two, Accra and Addis Ababa) on how to tailor their air quality policies. This project feels like it could be scaled up!
In Sub-Saharan Africa, one example of policy success is the phaseout of leaded gasoline as of late last year. Lead is an especially bad pollutant; phasing out leaded gasoline is surely a step in the right direction for dealing with air pollution.
For indoor air pollution due to burning fossil fuels, continued electrification is an important mitigating factor. Currently, just under half the population of Sub-Saharan Africa has access to electricity in their homes. When you have an electric stove, you no longer need to cook with solid fuel inside! Of course, this approach is especially beneficial if Africa’s energy mix comes to rely more heavily on renewables than on fossil fuels… more on that later.
An additional potential intervention is desulfization. Since fossil fuel emissions are most concentrated at the industrial sites where they are burned, and since coal is the worst offender for emissions, one idea to mitigate PM2.5 pollution is to install “scrubbers” at coal power plants to remove some or all sources of PM2.5, especially sulfur. Open Philanthropy says, “Coal power generation contributes approximately 15% of India’s PM2.5 emissions. Installing scrubbers reduces PM2.5 emissions by at least 80%. The selected coal power plants are responsible for 75% of the sector’s DALY costs. The health effects of air pollution in India cost approximately $2.68 trillion/year…” An intervention to speed up the installation of coal scrubbers (already government mandated) by 5 years could be highly cost-effective, but Open Phil isn’t confident that all these assumptions are accurate and thinks the effectiveness of this particular intervention might be lower. (Open Phil has recommended $3 million in funding to build a network of air quality monitors in India, but hasn’t funded any other interventions in South Asian air quality. But excitingly, they have in the past month hired a new Program Officer for South Asian Air Quality! I am excited to see what they do in this space.)
One more outside-the-box intervention: Heft-Neal et. al study dust in Sub-Saharan Africa as a source of PM2.5 concentration. The Bodélé Depression is one of the few non-anthropogenic sources of PM2.5 of its scale, and it has significant impact on West African nations. Like the authors suggest, perhaps we should study possible experimental interventions for regions affected by Saharan dust and other non-emissions-based PM2.5, such as pumping water into the Bodélé Depression (with the major caveat that this could have sweeping unintended effects and requires more study!).
What impact could low-cost AQMs have?
Monitoring is probably the most cost-effective intervention in Sub-Saharan African air quality. “By installing a small monitoring network, the contribution of industrial sources, power plants, area sources and that of transboundary dispersion of air pollutants could be assessed. In order to be able to interpret monitoring data in terms of their potential impact on human health and the environment, AQS [air quality standards] should be promulgated, which are reasonably enforceable” (World Bank).
Adding low-cost monitoring capacity seems to be effective, in that it improves our understanding of PM2.5 concentration significantly in areas without much on-the-ground monitoring. Satellite data is only so good (Malings et. al). Imagine being able to do studies like this in Lagos or Kinshasa! The impact is potentially transformative. So far, I have found two solid studies of the impact of low-cost AQMs, MacFarlane and Amegah:
MacFarlane et. al (2021): “Low-cost sensors have the potential to improve air quality data coverage throughout the world, especially in resource-limited areas (Amegah, 2018). For LCSs to provide high-quality data, understanding local conditions is vital.” They cite the cost of the PurpleAir system at $250 each, but no detailed budget is given for calibration and monitoring.
Amegah (2018): This is, to my knowledge, the only academic study concerned with the impact of adding low-cost AQMs in Sub-Saharan Africa. He finds that, “in a region that is bereft of air pollution data, the growing influx of low-cost sensors represents an excellent opportunity for bridging the data gap to inform air pollution control policies and regulations for public health protection. However, it is essential that only the most promising sensor technologies that performs creditably well in the harsh environmental conditions of the region are promoted.”
Map of existing PurpleAir monitors in Africa (as of 1 Feb 2022):
And South Asia:
My thoughts here are the most uncertain/reliant on my own synthesis. That said, I am excited about the possibilities afforded by potentially expanding our understanding of air quality in the hardest-hit regions.
Here’s my pitch: Deploy a network of low-cost monitoring stations throughout Sub-Saharan Africa and South Asia. This could be a good intervention for a new or existing effective altruist organization to pursue.
This would represent an improvement over current air quality monitoring systems, giving us more fine-grained data with lower error bars. It would be especially effective in areas with few monitoring stations already in use - which only rules out precious few locations in these regions.
Off the shelf, a PurpleAir AQM costs $250. For a network of 1000 sensors, that costs $250,000. We would want sensors to be deployed in a wide variety of locations; perhaps we stipulate at least three per country, at least one for every city over 1 million people, at least five for every city over 5 million people (or any other set of reasonable parameters). Each sensor has to make its way to a location in one of these regions, which costs money; it has to be installed semi-permanently, drawing electricity (although I think very little - they say 1 Watt of power, perhaps $1 per year) and Wi-Fi connectivity. So identifying willing hosts and shipping them the sensors is an additional cost - and perhaps one could incentivize hosting an AQM with a cash gift. The data from each sensor shows up in the PurpleAir network, where they provide access to all data for free. Researchers could then analyze that data and use it to publish findings that policymakers could use. Realistically, unless there are huge unforeseen costs (please let me know if you think you can identify any), this intervention could cost less than $1 million for a 3-5 year run time.
The data gathered from this sensor deployment would be worthwhile for its own sake, but one could imagine using it to work toward more targeted policies. For instance, perhaps we choose the three (or five or ten) countries most impacted by PM2.5, examine their current air quality standards and state capacity, then draw up policy documents to advocate for local policy change. Make the connection between the successful drive for unleaded gasoline and health, plus infant mortality, health cost savings, increased productivity, the whole cost-benefit analysis. Help steer some easily enforceable air quality standards across the finish line, making incremental progress. (This plan is, at first glance, likely to be especially effective in countries that haven’t already developed their own air quality plans.)
Conclusion - What is still unknown?
This is not intended to be read as a policy document, or even as a call to arms. I am a generalist, not a subject-area expert. So I’ll be the first to say that there’s every chance this sensor deployment initiative is half-baked for any number of reasons. (If you could point them out to me, I would see if possibly refining the idea would address concerns, which would help very much!)
In particular, I’m quite confident that a more detailed cost-effectiveness analysis would improve this idea significantly, giving a more nuanced understanding of what’s possible here. I’d also like to discuss this with people making grants in this space, as well as anyone who has logistics experience in the relevant regions on development-related projects in the past. I think people who are professionally involved in this space would probably have some actionable feedback for this idea.
I do know, however, that air pollution is really bad. If we want to address air pollution effectively, it would be really nice to get a lot more data about it. And the relevant data-gathering instruments seem widely available for anyone who wants to try.
PS. If you live in India or any other country in South Asia or Sub-Saharan Africa and want an air quality monitor, I will directly sponsor one PurpleAir monitor right now - please get in touch with me! jlcunningham3 at gmail dot com. Let’s try this out…