> With increasing evidence that chronic exposure to PM2.5, a neurotoxin, not only damages lungs and hearts but is also associated with dementia, probably not.
PM2.5 is not a neurotoxin, that's an absurd thing to say.
It's literally any particles under a certain size. Whether it's a neurotoxin is necessarily going to depend on what the substance is made of.
Whether your PM2.5 exposure is coming from automobiles or wildfires or a factory, the potential outcomes may be different in different areas of the body. Heck, my PM2.5 meter skyrockets whenever I cook anything in a frying pan, because many of the aerosolized oil droplets are PM2.5.
From what I've read apparently pretty much all PM2.5 encountered by most people has neurotoxic effects.
It looks like there are a couple reasons for this.
1. There are a lot of substances that are neurotoxic. Most things that create PM2.5 pollution will involve some of them.
2. PM2.5 is good at getting to places where the body really doesn't like foreign objects and so the mere presence of PM2.5 particles can trigger responses, such as inflammation, that can cause neurological damage even if the particle itself is made of a normally non-toxic substance.
Frying pan PM2.5 is pollution, and has been linked to increased childhood asthma, on of the easier and more immediate readouts from exposure. Linking dementia to that is a far harder scientific task due to the amounts of exposure and variability over time. Here's one blog post going over some of the evidence linking gas stoves to asthma:
The point is that your link seems to be almost entirely talking about something else (pollutants from burning gas inside, which is primarily NOx)! There is one passing mention of gas stoves producing some extra PM2.5 (which I expect will be different in composition to the PM2.5 produced in the pan) but all of the rest of it seems to be focused on the NOx
OH! Thank you for pointing out the error! I seem to have pasted the wrong link, and am not on my computer that I was doing the searching on before... please accept this short book chapter instead, though it is far more dry than the page I remember reading before.
That poster seemed to be saying that frying pan PM2.5 was not a health risk:
> Heck, my PM2.5 meter skyrockets whenever I cook anything in a frying pan, because many of the aerosolized oil droplets are PM2.5.
I'm not sure how they determined that PM2.5 is not a neurotoxin, or the full extent of their claims, but frying pans inside are a common cause of minor health problems.
> That poster seemed to be saying that frying pan PM2.5 was not a health risk
They said that the category "small particles" is not equal to the category "neurotoxic".
Much like how "Walks on Two Legs" is not "Men", there may be some overlap in the categories, but the first does not reliably
indicate the second. (Or vice-versa.)
The point was that PM2.5 is a measurement of particle size, and that by itself allows no judgement about its toxicity. The same way you cannot argue that things of 5 centimeter diameter are healthy.
The toxicity judgement comes from the information what substance has the form of PM2.5, and the journo managed to omit that.
> The point was that PM2.5 is a measurement of particle size, and that by itself allows no judgement about its toxicity.
This does not logically follow at all. The size indicates where it can reach in the lungs, whether cilia can eject it, etc.
A 5cm ball shot at the head at high speed is indeed dangerous. We are talking about inhalation of particles causing irritation, and the size is indeed the major factor. Content as well, but frying pan particles filled with carbon chains that have gone through who knows what reactions are indeed of concern. Lots of extremely nasty things are easily accessible from chains of hydrocarbons, from toluene to formaldehyde.
> The toxicity judgement comes from the information what substance has the form of PM2.5, and the journo managed to omit that.
I believe the journalist is not at fault here in the least. The scientific papers I have seen usually class all PM2.5 together, and perhaps by source. But the size itself is of great concern due to the size allowing easy entry to the body that is not possible for larger sizes.
There is nothing inherently impossible about the idea that all airborne substances of some specific size are harmful to breathe. It simply requires that they be bad because they physically fit into somewhere that shouldn't have foreign substances of any kind in it rather than because of something specific to the substance.
Many studies show a high correlation with childhood respiratory defects and living near roads (or even attending school near roads) specifically a road with diesel truck traffic, and a recent study showed a decrease in effects when air filters are installed in the schools.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6949366/
This is what frustrates me the most about air pollution indexes. They all treat PM2.5 equally regardless of the source. Smoke from a wildfire in an industrial area is NOT the same as smoke from a wildfire in a woodland. Hell, even some pollen fragments can be PM2.5. Formaldehyde and benzene particulate matter should not be treated equally to pollen fragments
Formaldehyde and benzene are to volatile to condense onto or absorb into PM2.5 particles. Cooking oil particles can contain other toxic compounds formed during heating, including polycyclic aromatic hydrocarbons (PAHs), acrolein, and various aldehydes and ketones. If formaldehyde or benzene react to form less volatile products, those reaction products might become part of particulate matter, but they're no longer formaldehyde or benzene at that point. So while cooking emissions do produce both harmful VOCs and harmful PM2.5 simultaneously, they remain distinct categories of pollutants.
Sure, but asbestos, lead, formaldehyde, benzene, etc particulate matters are all undoubtedly going to be more harmful than most types of wood smoke. An urban area will have both wood smoke (which is often treated, possibly with methyl bromide) and industrial smoke. Few would deny breathing in campfire smoke is less likely to cause more immediate harm than a fire at a waste site
I was initially skeptical of this claim because I’d previously learned that to cross the blood-brain barrier particles need to be ~200nm (PM2.5 = 2500nm). However, PM2.5 does seem to be an important category of particles for brain damage: somehow these particles can access the brain [1]. Obviously, yes, it depends on exactly the particle whether it will be “neurotoxic,” but generally “unnatural” particles in the brain are not going to do good things. (I am not an expert in particulates) it seems like things larger than this don’t penetrate the blood-brain barrier, so they can’t be neurotoxic. So PM2.5 is probably at an intersection of large enough to be unhealthy but small enough that the blood brain barrier doesn’t help (probably some evolutionary argument to be made here).
The article does suggest the particles travel "from the nose to the brain", but I think that may be a bit of hyperbole.
In the studies described, they weren't looking for these particles in the brain.
There is potentially a case to be made that the particles result in systemic inflammation, or some other pathway which leads to effects in the brain, rather than a direct action.
I don’t know. Pm2.5 by definition doesn’t include gasses and as I understand it the issue is that the particulate matter, whatever it happens to be, gets in the bloodstream. Is there any particulate matter of that size that is not neurotoxic once it enters the bloodstream? I don’t know the answer but it seems like a legitimate question.
One would imagine that salt spray from the ocean (which can easily register as PM2.5) is mostly sodium chloride, is rather water-soluble, and is entirely harmless in your bloodstream in any quantity that you could plausibly inhale.
There are a lot of things wrong with this. Almost anything under 2.5nm is going to weigh <500 daltons, which will cross the blood brain barrier, allowing it to have neurotoxic effects.
Yeah, very silly statement for them to write. I wouldn't be the slightest bit surprised if certain pollutants in that range were proven or will be proven to be causing gradual damage to the brain but that has to be presented properly.
> PM2.5 is not a neurotoxin, that's an absurd thing to say.
Indeed, imagine seeing "... chronic exposure to 5 ML, a chemical poison, not only...". Not sure how they can mistake a measurement for what the particles actually are.
Still doesn't make sense to claim that "PM2.5" is a neurotoxin, depends entirely on what the specific particles are, not the size of them.
What is more dangerous, PM2.5 or PM10? Well, naturally, smaller particles are more harmful to humans usually, but without knowing what the particles are, it's impossible to tell. Just like "5ML is/isn't more dangerous than 10ML", it doesn't really tell us anything.
Eh I'd give the author a bit of a benefit of the doubt. It's probably just sloppy writing for identifying correlation but not causation. PM2.5 particles themselves are not categorically neurotoxins; they just happen to be associated with other neurotoxins, such that high PM2.5 is a good proxy for high neurotoxin pollutants.
What really stands out is how subtle the damage can be. You're not coughing or wheezing, you're just slowly accumulating risk for something that might not show up for dades
First reaction: air pollutants correlate with urban living, which correlates with access to specialized health care, which correlates with detection of dementia.
While urban living does correlate with better access to healthcare, it also correlates with other dementia risk factors like chronic stress, social isolation
These sorts of pollution are largely caused by building massive amounts of car infrastructure and not building transit instead. The health effects extend beyond the direct pollution exposure to lifestyle things such as inactivity social isolation, and more.
And yet the US largely bans healthier, denser living by law. Density grows out of less dense areas, and those less dense areas nearly all have strict density caps preventing density, as well as road infrastructure designed to never allow density. And the dense areas of the country, which already show healthier lives for people and longer lifespans, have similarly tight caps on building more density
All this is to say that we have made a political choice as a society and are now reaping what we have sown. However we can choose something better for the future.
Your proposal flies in the face of what people actually want. Everyone wants a detached home with a yard. No one wants to live in a condo, an oct or a quad, or even a row house, as a permanent life-long dream. Not the people who currently own detached homes and not the people looking to buy homes. Everyone sees high-density housing as a stepping stone towards detached home ownership. Detached home ownership is the dream, the more land it comes with, the better.
How funny, having grown up in a rural area, I'd never live one again due to the madness, filth, and ugliness! I hope we both have ample choices for the ways we choose to live.
Noise in cities is mostly from cars, as is the dirt and death and destruction. Which is why I advocate so hard for allowing low car lifestyles and building, something that is largely banned in the US.
> How funny, having grown up in a rural area, I'd never live one again due to the madness, filth, and ugliness!
The only reason there would be madness, filth and ugliness in a rural area is if you left it there, because you are the only one living on your property.
Obviously, you have to sometimes go out into a hub of activity to get groceries or whatnot, but the onus is on you to provide evidence that those hubs are epicenters of madness and filth in a rural area, but not the urban area.
> because you are the only one living on your property.
This makes me think you don't actually live in a rural area. It's not like you're pioneering, no connection to the rest of society. There's still school for the kids, church, stores, and yes, even neighbors.
Plus, most humans find having a social life to be one of the greatest joys in life.
I find it fascinating that you think it's acceptable to call cities centers of madness, filth, and ugliness, but think it's completely unacceptable to think that of rural areas. Have you actually lived in a city? Or are you just basing it off of perceptions you get from media?
Many people have romantic notions about the country. Reality is there are “good” areas and bad. Lots of helplessness and poverty, shitty agricultural and industrial operators destroying the environment.
The beautiful areas are breathtaking if you can afford to live there.
I experienced both. I grew up in a beautiful pastoral landscape with prosperous dairy operations and a mix of tourism and small business. Small scale dairy farming is dead, and that death caused a chain reaction. My old home is a rural ghetto at this point. Distribution centers are the big thing that was supposed to save the day, but they have high turnover and generate truck traffic and other issues.
The only reason there would be madness, filth and ugliness in a rural area is if you left it there, because you are the only one living on your property.
My childhood friend's grandfather owned a silage plant. Ever smelled silage?
The local pig farm has created the worst smell I've ever directly experienced, and it's been a problem since the 90s.
These are just a few examples of filth and ugliness. As for madness, meth use and inattentive, drunk, or road-raging pickup truck drives with provide you that.
I see that you have the full experience. Has a person really lived until they have experienced the smell of a pig barn a mile away being cleaned out? Maybe "lived" is the wrong word but damn will it give you new nasal experiences that are beyond description. Around me, it was mostly the turkey barns, but I drove by enough pig barns that I know it's equally horrifying.
There's too much "trad life" larping on Instagram these days, and one of the many many parts of the experience that viewers miss is smell.
Sure, that's your personal preference and to each their own. The market speaks otherwise. Detached homes are the most desirable section of the real estate market based on consumer surveys, see the greatest growth in value compared to other real estate over the medium to long term and are basically recession proof. Even in the financial crisis of 2008-2009, the average loss was 10-15% in market value, which was recouped over the next five years.
The only consumer survey they actually reveals preferences is the price that people are willing to pay. Ask them questions in isolation and you miss all the implicit tradeoffs inherent to the questions.
And on that front, prices in dense areas are way way above suburban areas. Even if you subtract the lawn. People will pay far far more per sqft for a home in a dense urban area without a lawn! Which indicates that dense living is far undersupplied.
Not coincidentally, we don't have to ban suburban living, we only ban dense living. Literally anybody could buy an apartment building, tear it down and build a single family home, but how often do you ever see that happen? But you can't go the other direction, by law.
The market shows we do not have enough housing first and foremost. Many people care most of all about the cost, which is why people live in terrible buildings, so denser housing which can lower housing costs is the only real solution to increasingly unaffordable housing. Real estate is recession proof because we have effectively banned new housing which creates a massive rent seeking wealth transfer to those holding onto land simply by being there first
Single family homes have more sqft, so of course there is a higher price ceiling! That’s…very intuitive. There’s also less of them, because they take up so much space, so…doesn’t surprise me that they would be more at a “premium”. Assuming it’s in a desirable location.
One more thing to consider - no U.S. city has “excellent” infrastructure so it’s difficult to know what the demand would be like if that kind of city existed in the US. NYC doesn’t count, the subway is good by US standards but it’s junk compared to asia standards. Slow, loud, disgusting, lots of delays and maintenance on weekends.
For example how much would a nice apartment in manhattan be worth if i could easily hop on a bullet train and be in the Hamptons on Long Island within 50 minutes? Or in Mystic Connecticut within 45 minutes?? Suddenly commuting from the suburbs daily, so i can relax in nature on the weekends loses its appeal. Just one example.
With that said it’s good the market offers different housing “products” based on personal preference or life-stage (young, kids, older, etc)
Most people, even in the US, don’t live in detached homes with a yard. The amount of sprawl required to accomplish that “dream” of everyone living in a detached home with a huge yard would be a disaster for the environment and commutes.
In 2023, 54% of the housing units in the US were single family detached, https://eyeonhousing.org/2024/10/owner-occupied-single-famil.... I guess some of those could not have yards, but that is pretty rare to not have any sort of yard in a single family detached home.
2/3 of home buyers have single family detached as their preferred housing, so more people want to live in that type of housing than currently do so.
In the area with which I'm familiar it's a zoning/planning requirement to dedicate some proportion of lot area to yard. I forget the details -- it's been a while since I dug into this. I think that's also why mother in law units became popular in some jurisdictions: a workaround for yard area requirements since it piggy backs on the existing home yard arrangement.
Hear hear! Thank you. People are downvoting like mad because they want to drive their own agendas and are afraid of reality, except reality stands undefeated. Everyone wants a piece they call their own. Fighting against it is fighting against basic human nature. Give up your climate agenda. It's dead. Even Bill Gates said it.
No. You are being downvoted because observable facts support the opposite of your claims; and because you have apparently ignored many people who pointed out several things wrong with your claim — in a variety of ways — to cherry-pick someone who agrees with you; and because you propose to generalize the feelings of other people who are speaking up that they don't feel the way you imagine that "everyone" does; and because you are casting aspersions on others.
What you chose to argue against, by its nature, does not require evidence. The entire point is that you made a universal claim about what other people think. Others saying "I do not think that way" disproves your claim. It is not necessary for others to evidence that they don't think that way; saying so ipso facto establishes it.
Much of the rest of what is said here contra your viewpoint is also readily observable common knowledge.
I would suggest you read the Gates report. I'm not sure how much to engage here, except to say emphatically that Gates said nothing of the sort. TL;DR - health and development funding should be considered as a more marginally impactful form of foreign and domestic government investment, but only because of the rapid (and ongoing) progress already seen in emissions reduction.
Here's a quote:
> To be clear: Climate change is a very important problem. It needs to be solved, along with other problems like malaria and malnutrition. Every tenth of a degree of heating that we prevent is hugely beneficial because a stable climate makes it easier to improve people’s lives.
Reducing sprawl is plainly a good strategy to reduce transportation and infrastructure needs, and preserve wildlife.
Your comment would be a lot better if you didn't use words like "everyone" and "no one".
You'd be correct if you referred to some people, but acknowledged that for plenty of people, a detached home with a yard is the last thing they want. Lawn care and home maintenance, no thanks. Let me just pay a fee for my share of building maintenance, please.
This is some suburban delusion. Do you think the people who own multimillion dollar condos in NYC would rather live in a single family home? What's stopping them?
I want to be in the heart of a bustling city where I can walk to everything and do something different every night. That's not possible in suburbia.
I in fact want none of the things you claim. I have zero interest in living in the burbs, in maintaining a yard. It is in fact my long term dream to live in the city in my wonderful apartment until I cark it.
How bizarre you think you can talk for literally everyone in existence.
I want to live in a condo rather than detached home. Private home is too much of a hassle to maintain properly and also less likely to have many different shops/restaurants within 5 min walk
Absolutely untrue. My own desires are quite the opposite of what you describe. Besides which, tiny downtown places can often be more expensive than considerably larger ones in the suburbs.
Air purifiers are capable of removing PM2.5. Most people can get one under $150. I found that unused second-hand ones are abundant on Craigslist, eBay, etc. Get one that doesn't have ozone. I found that the Winix's ozone runs even when turning it "off".
There are reviews online that also take into account long-term cost (including the price of the filters themselves and how often they need to be replaced).
Probably not true per capita. In the suburb I partially grew up with they would kidnap homeless people and bus them to the nearest city. This is quite common throughout California and many red states.
Suburbs have more cars per capita, more driving in general, more asphalt,[0] more time commuting/being on the streets to reach common destinations, more exposure to smoke from fires, and sometimes even more exposure to pollutants and pesticides from farming (especially if they have golf courses. Golf courses use about 5x more pesticides than farmland per acre). Suburbs also have more suicides per capita than cities
AFAIK generally health studies don't distinguish all that much between urban and suburban, partially because that would require you to come up with a consistent definition of both; and even across states in the US, the definition of a "city" is wildly inconsistent and more a reflection however the politics of a place evolved.
It’s really hard to study because population is so diffuse and sometimes don’t align with geography.
My mom used to work in public health research, and one example that was hard to quantify was suspected cancer clusters around roads that were oiled gravel, where the oil was contaminated with industrial waste products. Basically, people who were outside in the summer near a road seemed to get lung cancer at higher rates due to road dust.
Issue was there just weren’t enough people or documentation of the supply chain to really prove it. They were able to stop the process of “donating” waste products to the highway departments.
In an urban environment, it’s easy. There are probably 500,000 people living along busy commercial corridors in NYC where you can reliably measure stuff like exposure to diesel particles or whatever.
“ After controlling for socioeconomic and other differences, the researchers found that the rate of Lewy body hospitalizations was 12 percent higher in U.S. counties with the worst concentrations of PM2.5 than in those with the lowest.”
https://www.nytimes.com/2025/11/01/health/alzheimers-dementi...
> With increasing evidence that chronic exposure to PM2.5, a neurotoxin, not only damages lungs and hearts but is also associated with dementia, probably not.
PM2.5 is not a neurotoxin, that's an absurd thing to say.
It's literally any particles under a certain size. Whether it's a neurotoxin is necessarily going to depend on what the substance is made of.
Whether your PM2.5 exposure is coming from automobiles or wildfires or a factory, the potential outcomes may be different in different areas of the body. Heck, my PM2.5 meter skyrockets whenever I cook anything in a frying pan, because many of the aerosolized oil droplets are PM2.5.
From what I've read apparently pretty much all PM2.5 encountered by most people has neurotoxic effects.
It looks like there are a couple reasons for this.
1. There are a lot of substances that are neurotoxic. Most things that create PM2.5 pollution will involve some of them.
2. PM2.5 is good at getting to places where the body really doesn't like foreign objects and so the mere presence of PM2.5 particles can trigger responses, such as inflammation, that can cause neurological damage even if the particle itself is made of a normally non-toxic substance.
Frying pan PM2.5 is pollution, and has been linked to increased childhood asthma, on of the easier and more immediate readouts from exposure. Linking dementia to that is a far harder scientific task due to the amounts of exposure and variability over time. Here's one blog post going over some of the evidence linking gas stoves to asthma:
https://www.health.harvard.edu/blog/have-a-gas-stove-how-to-...
Gas stoves produce NO2, not PM2.5.
https://www.cieh.org/ehn/environmental-protection/2025/april...
Quote: Research shows cooking on domestic gas hobs can cause two of the most harmful air pollutants, NO2 and PM2.5, to exceed WHO guidelines
Frying pans produce PM2.5, gas stove or no. I am talking about PM2.5. What is your point?
The point is that your link seems to be almost entirely talking about something else (pollutants from burning gas inside, which is primarily NOx)! There is one passing mention of gas stoves producing some extra PM2.5 (which I expect will be different in composition to the PM2.5 produced in the pan) but all of the rest of it seems to be focused on the NOx
You link to a report about gas stoves not frying pans.
OH! Thank you for pointing out the error! I seem to have pasted the wrong link, and am not on my computer that I was doing the searching on before... please accept this short book chapter instead, though it is far more dry than the page I remember reading before.
https://www.ncbi.nlm.nih.gov/books/NBK385529/
Apologies!
Ah - that makes more sense.
How is that related to what GP wrote?
That poster seemed to be saying that frying pan PM2.5 was not a health risk:
> Heck, my PM2.5 meter skyrockets whenever I cook anything in a frying pan, because many of the aerosolized oil droplets are PM2.5.
I'm not sure how they determined that PM2.5 is not a neurotoxin, or the full extent of their claims, but frying pans inside are a common cause of minor health problems.
> That poster seemed to be saying that frying pan PM2.5 was not a health risk
They said that the category "small particles" is not equal to the category "neurotoxic".
Much like how "Walks on Two Legs" is not "Men", there may be some overlap in the categories, but the first does not reliably indicate the second. (Or vice-versa.)
The point was that PM2.5 is a measurement of particle size, and that by itself allows no judgement about its toxicity. The same way you cannot argue that things of 5 centimeter diameter are healthy.
The toxicity judgement comes from the information what substance has the form of PM2.5, and the journo managed to omit that.
> The point was that PM2.5 is a measurement of particle size, and that by itself allows no judgement about its toxicity.
This does not logically follow at all. The size indicates where it can reach in the lungs, whether cilia can eject it, etc.
A 5cm ball shot at the head at high speed is indeed dangerous. We are talking about inhalation of particles causing irritation, and the size is indeed the major factor. Content as well, but frying pan particles filled with carbon chains that have gone through who knows what reactions are indeed of concern. Lots of extremely nasty things are easily accessible from chains of hydrocarbons, from toluene to formaldehyde.
> The toxicity judgement comes from the information what substance has the form of PM2.5, and the journo managed to omit that.
I believe the journalist is not at fault here in the least. The scientific papers I have seen usually class all PM2.5 together, and perhaps by source. But the size itself is of great concern due to the size allowing easy entry to the body that is not possible for larger sizes.
There is nothing inherently impossible about the idea that all airborne substances of some specific size are harmful to breathe. It simply requires that they be bad because they physically fit into somewhere that shouldn't have foreign substances of any kind in it rather than because of something specific to the substance.
To be just a touch pedantic, that all particles of a certain size are harmful is a silly assertion.
Water and sugar particles, for instance, are almost certainly harmless below some reasonable threshold.
Small enough particles can easily pierce the blood brain barrier. https://pmc.ncbi.nlm.nih.gov/articles/PMC10141840/ They also appear to interact with human gut microbiota. https://pmc.ncbi.nlm.nih.gov/articles/PMC11056917/
What they do there is up for further study.
Many studies show a high correlation with childhood respiratory defects and living near roads (or even attending school near roads) specifically a road with diesel truck traffic, and a recent study showed a decrease in effects when air filters are installed in the schools. https://pmc.ncbi.nlm.nih.gov/articles/PMC6949366/
This is what frustrates me the most about air pollution indexes. They all treat PM2.5 equally regardless of the source. Smoke from a wildfire in an industrial area is NOT the same as smoke from a wildfire in a woodland. Hell, even some pollen fragments can be PM2.5. Formaldehyde and benzene particulate matter should not be treated equally to pollen fragments
Formaldehyde and benzene are not particulates, they are VOC’s - a very different kind pollutant.
But PM2.5 from, say, a frying pan could easily contain abundant formaldehyde and benzene as part of the oil particles.
Formaldehyde and benzene are to volatile to condense onto or absorb into PM2.5 particles. Cooking oil particles can contain other toxic compounds formed during heating, including polycyclic aromatic hydrocarbons (PAHs), acrolein, and various aldehydes and ketones. If formaldehyde or benzene react to form less volatile products, those reaction products might become part of particulate matter, but they're no longer formaldehyde or benzene at that point. So while cooking emissions do produce both harmful VOCs and harmful PM2.5 simultaneously, they remain distinct categories of pollutants.
Lumping all PM2.5 together is kind of like counting calories without considering whether they come from broccoli or corn syrup
OK, but wood smoke is really bad for you even if the wood is completely natural.
Sure, but asbestos, lead, formaldehyde, benzene, etc particulate matters are all undoubtedly going to be more harmful than most types of wood smoke. An urban area will have both wood smoke (which is often treated, possibly with methyl bromide) and industrial smoke. Few would deny breathing in campfire smoke is less likely to cause more immediate harm than a fire at a waste site
yes but smoke from any urban area will have asbestos and numerous other potent toxins
Pollen fragments are really bad for some of us....
Of course! Different bodies have different sensitivities. But we're talking averages here. What's gonna cause the most social harm
I was initially skeptical of this claim because I’d previously learned that to cross the blood-brain barrier particles need to be ~200nm (PM2.5 = 2500nm). However, PM2.5 does seem to be an important category of particles for brain damage: somehow these particles can access the brain [1]. Obviously, yes, it depends on exactly the particle whether it will be “neurotoxic,” but generally “unnatural” particles in the brain are not going to do good things. (I am not an expert in particulates) it seems like things larger than this don’t penetrate the blood-brain barrier, so they can’t be neurotoxic. So PM2.5 is probably at an intersection of large enough to be unhealthy but small enough that the blood brain barrier doesn’t help (probably some evolutionary argument to be made here).
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC9491465/#:~:text=PM...
The article does suggest the particles travel "from the nose to the brain", but I think that may be a bit of hyperbole.
In the studies described, they weren't looking for these particles in the brain.
There is potentially a case to be made that the particles result in systemic inflammation, or some other pathway which leads to effects in the brain, rather than a direct action.
I don’t know. Pm2.5 by definition doesn’t include gasses and as I understand it the issue is that the particulate matter, whatever it happens to be, gets in the bloodstream. Is there any particulate matter of that size that is not neurotoxic once it enters the bloodstream? I don’t know the answer but it seems like a legitimate question.
One would imagine that salt spray from the ocean (which can easily register as PM2.5) is mostly sodium chloride, is rather water-soluble, and is entirely harmless in your bloodstream in any quantity that you could plausibly inhale.
As I understand it you are incorrect. Salt from sea breeze is pm10 not pm2.5. My information may be inaccurate but google backs it up.
Amino acids!
I'm sure now some other HN poster will come up with an explanation how Amino Acids are still neurotoxic of some sort.
pm2.5 is a metric used in assessing air quality. Amino acid aerosols are not a source of air pollution.
amino acids droplets are pm2.5. pm2.5 refers to the particle size.
See what i wrote in the other thread... https://news.ycombinator.com/item?id=45784538
That's too easy, glutamate is neurotoxic in high doses.
What about sugar?
100% agree. It is super important to know the composition of the particles.
Unfortunately currently only super expensive instruments can measure this in real-time.
This is why I believe contextual information will become much more important in future.
Detect an indoor short PM2.5 spike around lunch time, probably a cooking event.
Detect medium elevated levels outdoor in a city in the morning and late afternoons, probably traffic related smoke.
I actually made a small tool to simulate different events that contain a quiz. Give it a try here [1].
[1] https://www.airgradient.com/air-quality-monitoring-toolkit/p...
The quiz hides the chart. Makes it hard to answer
Ideally we'd move toward more source-specific or composition-specific air quality standards but that's a much tougher data and policy problem
There are a lot of things wrong with this. Almost anything under 2.5nm is going to weigh <500 daltons, which will cross the blood brain barrier, allowing it to have neurotoxic effects.
Yeah, very silly statement for them to write. I wouldn't be the slightest bit surprised if certain pollutants in that range were proven or will be proven to be causing gradual damage to the brain but that has to be presented properly.
> PM2.5 is not a neurotoxin, that's an absurd thing to say.
Indeed, imagine seeing "... chronic exposure to 5 ML, a chemical poison, not only...". Not sure how they can mistake a measurement for what the particles actually are.
The "PM" in PM2.5 stands for "particulate matter", so it actually is a noun and not just a unit of measurement.
Still doesn't make sense to claim that "PM2.5" is a neurotoxin, depends entirely on what the specific particles are, not the size of them.
What is more dangerous, PM2.5 or PM10? Well, naturally, smaller particles are more harmful to humans usually, but without knowing what the particles are, it's impossible to tell. Just like "5ML is/isn't more dangerous than 10ML", it doesn't really tell us anything.
They might intentionally saying that something of that size is problematic.
Eh I'd give the author a bit of a benefit of the doubt. It's probably just sloppy writing for identifying correlation but not causation. PM2.5 particles themselves are not categorically neurotoxins; they just happen to be associated with other neurotoxins, such that high PM2.5 is a good proxy for high neurotoxin pollutants.
Previous discussions:
https://news.ycombinator.com/item?id=45157897 (129 comments)
https://news.ycombinator.com/item?id=44846164 (124 comments)
I recently found this blog post about an effective DIY air filter - explicitly filters pm2.5
https://chillphysicsenjoyer.substack.com/p/measuring-my-diy-...
I built one (< $50) and I'm pretty happy with the results. As someone with a life long sensitivity to air quality, the air definitely feels cleaner.
You really don't need to DIY unless you really want to. My non-DIY mass produced air filter from Home Depot can filter PM2.5 too.
Different strokes. I've been disappointed by every commercial air purifier I've ever bought - expensive and unreliable.
The blog is persuasive and provides a full air quality analysis. It's cheap and effective, a potent combination.
What really stands out is how subtle the damage can be. You're not coughing or wheezing, you're just slowly accumulating risk for something that might not show up for dades
Any recommendations for a good air quality monitor?
First reaction: air pollutants correlate with urban living, which correlates with access to specialized health care, which correlates with detection of dementia.
While urban living does correlate with better access to healthcare, it also correlates with other dementia risk factors like chronic stress, social isolation
These sorts of pollution are largely caused by building massive amounts of car infrastructure and not building transit instead. The health effects extend beyond the direct pollution exposure to lifestyle things such as inactivity social isolation, and more.
And yet the US largely bans healthier, denser living by law. Density grows out of less dense areas, and those less dense areas nearly all have strict density caps preventing density, as well as road infrastructure designed to never allow density. And the dense areas of the country, which already show healthier lives for people and longer lifespans, have similarly tight caps on building more density
All this is to say that we have made a political choice as a society and are now reaping what we have sown. However we can choose something better for the future.
Your proposal flies in the face of what people actually want. Everyone wants a detached home with a yard. No one wants to live in a condo, an oct or a quad, or even a row house, as a permanent life-long dream. Not the people who currently own detached homes and not the people looking to buy homes. Everyone sees high-density housing as a stepping stone towards detached home ownership. Detached home ownership is the dream, the more land it comes with, the better.
If people actually wanted that, you wouldn't have to ban denser living.
Our choices are not the result of a free market, but one highly constrained by land use restrictions.
This is seen very clearly in housing prices. Dense living is hugely undersupplied, and therefore very expensive.
> Detached home ownership is the dream, the more land it comes with, the better.
Not everyone wants to live in the country or the suburbs. I wouldn't live there if you paid me.
https://www.youtube.com/watch?v=93oFXRedHy0
As a country dweller I feel the same about the city. The city is an ugly, noisy, filthy hive of madness.
How funny, having grown up in a rural area, I'd never live one again due to the madness, filth, and ugliness! I hope we both have ample choices for the ways we choose to live.
Noise in cities is mostly from cars, as is the dirt and death and destruction. Which is why I advocate so hard for allowing low car lifestyles and building, something that is largely banned in the US.
So you traded trees for hard advocating.
Plenty of room for trees once there's fewer cars. Urban trees are great, and plentiful when they are planned for.
> How funny, having grown up in a rural area, I'd never live one again due to the madness, filth, and ugliness!
The only reason there would be madness, filth and ugliness in a rural area is if you left it there, because you are the only one living on your property.
Obviously, you have to sometimes go out into a hub of activity to get groceries or whatnot, but the onus is on you to provide evidence that those hubs are epicenters of madness and filth in a rural area, but not the urban area.
Your argument makes 0 sense without any evidence.
> because you are the only one living on your property.
This makes me think you don't actually live in a rural area. It's not like you're pioneering, no connection to the rest of society. There's still school for the kids, church, stores, and yes, even neighbors.
Plus, most humans find having a social life to be one of the greatest joys in life.
I find it fascinating that you think it's acceptable to call cities centers of madness, filth, and ugliness, but think it's completely unacceptable to think that of rural areas. Have you actually lived in a city? Or are you just basing it off of perceptions you get from media?
Many people have romantic notions about the country. Reality is there are “good” areas and bad. Lots of helplessness and poverty, shitty agricultural and industrial operators destroying the environment.
The beautiful areas are breathtaking if you can afford to live there.
I experienced both. I grew up in a beautiful pastoral landscape with prosperous dairy operations and a mix of tourism and small business. Small scale dairy farming is dead, and that death caused a chain reaction. My old home is a rural ghetto at this point. Distribution centers are the big thing that was supposed to save the day, but they have high turnover and generate truck traffic and other issues.
The only reason there would be madness, filth and ugliness in a rural area is if you left it there, because you are the only one living on your property.
Use of sulfur by farmers causes asthma: https://pmc.ncbi.nlm.nih.gov/articles/PMC5783654/
Stockyards smell awful.
My childhood friend's grandfather owned a silage plant. Ever smelled silage?
The local pig farm has created the worst smell I've ever directly experienced, and it's been a problem since the 90s.
These are just a few examples of filth and ugliness. As for madness, meth use and inattentive, drunk, or road-raging pickup truck drives with provide you that.
I see that you have the full experience. Has a person really lived until they have experienced the smell of a pig barn a mile away being cleaned out? Maybe "lived" is the wrong word but damn will it give you new nasal experiences that are beyond description. Around me, it was mostly the turkey barns, but I drove by enough pig barns that I know it's equally horrifying.
There's too much "trad life" larping on Instagram these days, and one of the many many parts of the experience that viewers miss is smell.
As someone who was a country dweller (born and raised) you couldn’t pay me any amount of money to return to it.
It’s nice we get the choice though, and I do like to visit it still. I could just never return to such isolation and poor services.
Mainly due to car industry friendly legislation and entitled suburbanites
Sure, that's your personal preference and to each their own. The market speaks otherwise. Detached homes are the most desirable section of the real estate market based on consumer surveys, see the greatest growth in value compared to other real estate over the medium to long term and are basically recession proof. Even in the financial crisis of 2008-2009, the average loss was 10-15% in market value, which was recouped over the next five years.
The only consumer survey they actually reveals preferences is the price that people are willing to pay. Ask them questions in isolation and you miss all the implicit tradeoffs inherent to the questions.
And on that front, prices in dense areas are way way above suburban areas. Even if you subtract the lawn. People will pay far far more per sqft for a home in a dense urban area without a lawn! Which indicates that dense living is far undersupplied.
Not coincidentally, we don't have to ban suburban living, we only ban dense living. Literally anybody could buy an apartment building, tear it down and build a single family home, but how often do you ever see that happen? But you can't go the other direction, by law.
The market shows we do not have enough housing first and foremost. Many people care most of all about the cost, which is why people live in terrible buildings, so denser housing which can lower housing costs is the only real solution to increasingly unaffordable housing. Real estate is recession proof because we have effectively banned new housing which creates a massive rent seeking wealth transfer to those holding onto land simply by being there first
Single family homes have more sqft, so of course there is a higher price ceiling! That’s…very intuitive. There’s also less of them, because they take up so much space, so…doesn’t surprise me that they would be more at a “premium”. Assuming it’s in a desirable location.
One more thing to consider - no U.S. city has “excellent” infrastructure so it’s difficult to know what the demand would be like if that kind of city existed in the US. NYC doesn’t count, the subway is good by US standards but it’s junk compared to asia standards. Slow, loud, disgusting, lots of delays and maintenance on weekends.
For example how much would a nice apartment in manhattan be worth if i could easily hop on a bullet train and be in the Hamptons on Long Island within 50 minutes? Or in Mystic Connecticut within 45 minutes?? Suddenly commuting from the suburbs daily, so i can relax in nature on the weekends loses its appeal. Just one example.
With that said it’s good the market offers different housing “products” based on personal preference or life-stage (young, kids, older, etc)
> Everyone wants a detached home with a yard. No one wants to live in a condo, an oct or a quad, or even a row house, as a permanent life-long dream.
This is easily disproven by the state of the real estate market and relative value of said urban condos to suburban sfh
OK. Since that's what people actually want, the market should work without single-family-home zoning laws and minimum parking requirements.
Glad to see different people want different things in life.
People want the single family, but they don’t want to pay for the externalities that come with sprawl.
Price in the full cost of that sprawl and it becomes less desirable.
Most people, even in the US, don’t live in detached homes with a yard. The amount of sprawl required to accomplish that “dream” of everyone living in a detached home with a huge yard would be a disaster for the environment and commutes.
In 2023, 54% of the housing units in the US were single family detached, https://eyeonhousing.org/2024/10/owner-occupied-single-famil.... I guess some of those could not have yards, but that is pretty rare to not have any sort of yard in a single family detached home.
2/3 of home buyers have single family detached as their preferred housing, so more people want to live in that type of housing than currently do so.
In the area with which I'm familiar it's a zoning/planning requirement to dedicate some proportion of lot area to yard. I forget the details -- it's been a while since I dug into this. I think that's also why mother in law units became popular in some jurisdictions: a workaround for yard area requirements since it piggy backs on the existing home yard arrangement.
Hear hear! Thank you. People are downvoting like mad because they want to drive their own agendas and are afraid of reality, except reality stands undefeated. Everyone wants a piece they call their own. Fighting against it is fighting against basic human nature. Give up your climate agenda. It's dead. Even Bill Gates said it.
No. You are being downvoted because observable facts support the opposite of your claims; and because you have apparently ignored many people who pointed out several things wrong with your claim — in a variety of ways — to cherry-pick someone who agrees with you; and because you propose to generalize the feelings of other people who are speaking up that they don't feel the way you imagine that "everyone" does; and because you are casting aspersions on others.
The only person who presented any evidence is the GP and it affirms my claim. Can you present the evidence you so speak of?
What you chose to argue against, by its nature, does not require evidence. The entire point is that you made a universal claim about what other people think. Others saying "I do not think that way" disproves your claim. It is not necessary for others to evidence that they don't think that way; saying so ipso facto establishes it.
Much of the rest of what is said here contra your viewpoint is also readily observable common knowledge.
I would suggest you read the Gates report. I'm not sure how much to engage here, except to say emphatically that Gates said nothing of the sort. TL;DR - health and development funding should be considered as a more marginally impactful form of foreign and domestic government investment, but only because of the rapid (and ongoing) progress already seen in emissions reduction.
Here's a quote:
> To be clear: Climate change is a very important problem. It needs to be solved, along with other problems like malaria and malnutrition. Every tenth of a degree of heating that we prevent is hugely beneficial because a stable climate makes it easier to improve people’s lives.
Reducing sprawl is plainly a good strategy to reduce transportation and infrastructure needs, and preserve wildlife.
Your comment would be a lot better if you didn't use words like "everyone" and "no one".
You'd be correct if you referred to some people, but acknowledged that for plenty of people, a detached home with a yard is the last thing they want. Lawn care and home maintenance, no thanks. Let me just pay a fee for my share of building maintenance, please.
This is some suburban delusion. Do you think the people who own multimillion dollar condos in NYC would rather live in a single family home? What's stopping them?
I want to be in the heart of a bustling city where I can walk to everything and do something different every night. That's not possible in suburbia.
> Do you think the people who own multimillion dollar condos in NYC would rather live in a single family home? What's stopping them?
They'd probably rather live in a single family home in NYC.
They have to choose between contradictory desires: single family home over condo, but NYC over suburbs or rural.
Has a lot to do with time of life too. I had similar feelings in 20s while single.
I in fact want none of the things you claim. I have zero interest in living in the burbs, in maintaining a yard. It is in fact my long term dream to live in the city in my wonderful apartment until I cark it.
How bizarre you think you can talk for literally everyone in existence.
I want to live in a condo rather than detached home. Private home is too much of a hassle to maintain properly and also less likely to have many different shops/restaurants within 5 min walk
> Everyone wants...
Absolutely untrue. My own desires are quite the opposite of what you describe. Besides which, tiny downtown places can often be more expensive than considerably larger ones in the suburbs.
… Eh, I think maybe you’re taking what _you_ want and assuming it is what everyone wants? Personally I couldn’t face living in the middle of nowhere.
live near a highway and can't afford to move, any ideas what I should do
Air purifiers are capable of removing PM2.5. Most people can get one under $150. I found that unused second-hand ones are abundant on Craigslist, eBay, etc. Get one that doesn't have ozone. I found that the Winix's ozone runs even when turning it "off".
There are reviews online that also take into account long-term cost (including the price of the filters themselves and how often they need to be replaced).
Use an air purifier with a HEPA filter, ideally one rated for your room size. Keep windows closed during rush hour or heavy traffic times
Air purifiers? Winix, Conway, IKEA etc
I think they have also done studies in rodents that show pm2.5 diesel particulate decreases insulin sensitivity.
Archive / paywall: <https://archive.is/86eOb>
Dementedness is higher in cities then, right?
What differences in behavior do we see between city and rural?
Probably not true per capita. In the suburb I partially grew up with they would kidnap homeless people and bus them to the nearest city. This is quite common throughout California and many red states.
Suburbs have more cars per capita, more driving in general, more asphalt,[0] more time commuting/being on the streets to reach common destinations, more exposure to smoke from fires, and sometimes even more exposure to pollutants and pesticides from farming (especially if they have golf courses. Golf courses use about 5x more pesticides than farmland per acre). Suburbs also have more suicides per capita than cities
[0] https://www.sciencedirect.com/science/article/abs/pii/S03043...
AFAIK generally health studies don't distinguish all that much between urban and suburban, partially because that would require you to come up with a consistent definition of both; and even across states in the US, the definition of a "city" is wildly inconsistent and more a reflection however the politics of a place evolved.
It’s really hard to study because population is so diffuse and sometimes don’t align with geography.
My mom used to work in public health research, and one example that was hard to quantify was suspected cancer clusters around roads that were oiled gravel, where the oil was contaminated with industrial waste products. Basically, people who were outside in the summer near a road seemed to get lung cancer at higher rates due to road dust.
Issue was there just weren’t enough people or documentation of the supply chain to really prove it. They were able to stop the process of “donating” waste products to the highway departments.
In an urban environment, it’s easy. There are probably 500,000 people living along busy commercial corridors in NYC where you can reliably measure stuff like exposure to diesel particles or whatever.
“ After controlling for socioeconomic and other differences, the researchers found that the rate of Lewy body hospitalizations was 12 percent higher in U.S. counties with the worst concentrations of PM2.5 than in those with the lowest.”
Not a very powerful effect.
the article is clearly a fear mongering one