Studies Increasingly Find Links Between Air Pollutants and Dementia

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-...

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

    > Cooking at very high temperatures (over 450°F or 232°C), especially with oils or fats, could theoretically contribute to benzene formation.

> 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.

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.

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...

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...

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.

Is this a bit like saying that bullets made from glass are healthier than those made of lead?

I thought some of the harm comes from the size of PM2.5 particles alone.

Ideally we'd move toward more source-specific or composition-specific air quality standards but that's a much tougher data and policy problem

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.

On second thought, i think this is intentional. If scientists interpolate from well-chosen substances onto all Pm2.5, it should be provable that earths atomosphere is toxic beyond limits and uninhabitable. "We destroyed earth" sells well and would justify further research funding.

</tinfoil-hat>

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.

They might intentionally saying that something of that size is problematic.

the article is clearly a fear mongering one

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.

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...

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.

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 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).

Air purifiers? Winix, Conway, IKEA etc

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.

While urban living does correlate with better access to healthcare, it also correlates with other dementia risk factors like chronic stress, social isolation