The air pollution thread

[AlexKChen]

Better air quality is the easiest way not to die

https://www.pnas.org/content/117/25/13856

see caleb finch too. and the mexico city pollution study on dogs near roadways and all the plaque they developed

Wear N95/N99 masks when on the subways or near major roadways. Thomas Talheim has a blog (smartairfilters.com) showing that even low-levels of PM1/PM2.5 found in American cities (even NYC/Chicago) are enough to increase inflammation/irritability levels. Do not live within 300 years of a major arterial roadway (esp one populated by trucks or diesel-emitting vehicles). The best air quality is found in US/Canada/ocean-touching areas of Europe. Most of the pollution from automobiles may be from cars causing friction against the asphalt (this is where all electric-powered subway pollution comes from!!), which means that some protection against PM2.5 is necessary even when we transition to all-electric (the amount of PM2.5 emitted here scales nonlinearly with the speed by which the car touches asphalt).

Stay away from laser printers (tho my pollution monitors have never picked up signal when they print). Or at least wear a N95 when next to one (though it’s not clear if they will filter out EVERYTHING - thoams talhelm says they PROBABLY filter out even the nanoparticles but one cannot be too sure). I totally remember feeling intense regret when forgetting to wear one when I randomly bolted from a group restaurant in Kotor, MNE and kept on having to face diesel fumes (luckily the PM2.5 never went above 15 during the isolated moments when a truck passed by me, but it still HURT)

Toxic ‘forever chemicals’ contaminate indoor air at worrying levels, study finds

Blast and sqair have best air purifiers

for monitors - https://smartairfilters.com/en/blog/best-pm2-5-air-quality-monitors-in-2021/

If you want to go to a unique extreme, semiconductor fabs have the most heavily filtered air ever - Semiconductor | Camfil

[how many particles per day does one breath in from PM2.5 of 7.5 (keep in mind that AVERAGE LIFETIME ingestion of PM2.5 is more like 10-15 integrated across a zillenial’s lifetime), and how does that compare to average daily intake of microplastics?]

[AlexKChen]

Office air quality may affect employees’ cognition, productivity

[AlexKChen]

Boston Air Quality Index (AQI) and Massachusetts Air Pollution | AirVisual

[AlexKChen]

[AlexKChen]

Lab Finds Billions of Air Pollution Particles in Human Hearts – Smart Air

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David FurmanDavid Furman • 1st • 1stAcademic entrepreneur, using Computational Immunology to extend healthspan and longevityAcademic entrepreneur, using Computational Immunology to extend healthspan and longevity4d • 4 days ago

HOW DO WE TARGET INFLAMMATION TO SLOW DOWN BIOLOGICAL AGING?

The list of long, but a few examples listed below. Healthy Longevity is Possible

Based on more than 10 years of research, I’ve concluded three pillars to follow:

1- Protect
2- Challenge
3- Repair

The first pillar PROTECT involves the so called ‘exposome’. Examples below and in the images more information regarding CHALLENGE and REPAIR.

Air quality, example: pollutants in the air we breath such as PM2.5 and PM10 increase inflammaging proteins such as Eotaxin-1 a key protein that accelerates BRAIN AGING. Formaldehyde, found in the air of houses with new furniture for example, increases CXCL9 levels a protein that accelerates CARDIOVASCULAR AGING.

Grains, dairy products, legumes; all highly inflammatory with known pro-aging pathways!

Processed foods, example: polysorbate-80, carboxymethyl cellulose found almost in every processed food, cause massive destruction of our MICROBIOME (dysbiosis) reducing the mucin layer in our gut with results in the leakage of luminal antigens into our peripheral circulation causing upregulation of many inflammaging cytokines including the NFkB system. By disrupting out microbiome we also eliminate important anti-inflammatory metabolites such as short chain fatty acids, produced by our gut microbiome.

Plastics, example: these are most everywhere and act as endocrine disruptors since they have similar chemical structure as sex hormones (increase risk of CANCER in women and feminize exposed men (shrinkage of testis size and enlargement of breast tissue! These also cause direct upregulation of inflammaging pathways NFkB, MyD88 and NLRP3 in terms of proteins and gene expression.

Commonly used drugs, example: Acetaminophen reduces levels of TRAIL an Inflammatory Age protein (higher is better here) involved in clearance of senescence cells.

[AlexKChen]

Prolonged exposure to pollution can lead to loss of independence in later...

[AlexKChen]

Road Hazard: Evidence Mounts on Toxic Pollution from Tires

[AlexKChen]

https://x.com/cremieuxrecueil/status/1914742023052988452

[LongevityVault]

Review of the epidemiological evidence of effects of air pollution on dementia, cognitive function and cognitive decline in adult population ( I would have embedded images but system wouldn’t allow me)

Delgado-Saborit JM, Guercio V, Gowers AM, Shaddick G, Fox NC, Love S. A critical review of the epidemiological evidence of effects of air pollution on dementia, cognitive function and cognitive decline in adult population. Sci Total Environ. 2021 Feb 25;757:143734. doi: 10.1016/j.scitotenv.2020.143734. Epub 2020 Nov 25. PMID: 33340865.

A critical review of the epidemiological evidence of effects of air pollution...

[AlexKChen]

Short answer

• Yes, ultrafine particles (UFP; <100 nm) are still present in both airport terminals and aircraft cabins, even though both places use high-grade filtration.
• Typical counts you’re likely to inhale
  • Inside Logan Airport’s terminals: usually ~3 000–10 000 particles cm-³, but brief spikes can exceed 20 000 particles cm-³ when a jet bridge is open or service vehicles idle nearby.
  • Cabin while cruising: a few hundred to a few thousand particles cm-³ (well below subway or highway levels).
  • Cabin during boarding, taxi, take-off or landing: short peaks of 30 000–100 000 particles cm-³ have been recorded when the APU or engines supply unfiltered “bleed air.”
  • Neighborhoods down-wind of Logan: outdoor counts routinely exceed 20 000 particles cm-³ and can run 40 000 + during heavy traffic or westerly winds.

Because UFPs penetrate more deeply into the lungs and are not removed as efficiently by the body as PM₂.₅, even those short bursts matter for people with asthma, cardiovascular disease or heightened pollution sensitivity.

Why filtration doesn’t make them vanish

Location	Filtration hardware	Removal efficiency vs UFP (<100 nm)	What still gets through
Aircraft cabin (most jets)	Recirculated air passes through HEPA (≥ 99.97 % at 0.3 µm; diffusion makes capture higher, ≈ 99 – >99.9 % for 20–100 nm)	Ambient or engine/APU-generated UFPs whenever fresh bleed-air is pulled in (no filter upstream) + brief “fume events”.
Logan terminals	Central HVAC MERV-14/HEPA plus high air-change rates	Jet-bridge leaks, baggage tugs, idling buses, construction dust; outdoor exhaust infiltrates whenever doors open.
Gate area/jet way	Little to no filtration; air pulled from ramp	Direct exhaust plumes and APU bleed-air can give 10× terminal background for a few minutes.

Key point: Filtration only acts on recirculated air. Whenever outside or engine air is first drawn in, you get an unfiltered slug—and UFP peaks are entirely number-based, so even tiny masses make big counts.

Boston-specific numbers in context

Environment	Median particle number (PNC) cm-³	Typical duration
Quiet residential indoor (Boston baseline)	2 000–4 000
Logan terminal seating areas	3 000–10 000
Gate while aircraft hooked to jet-bridge + APU running	10 000–25 000 for 2–10 min
Cabin cruise (HEPA recirc)	300–2 000
Cabin taxi/climb peaks	30 000–100 000 for 10–60 s
East-Boston outdoor, wind from runways	19 000 (median); peaks > 40 000

For comparison, a typical downtown Boston rush-hour street is 25 000–60 000 particles cm-³; the Red-Line subway platform routinely tops 50 000–80 000.

Should you mask up?

• Effectiveness: Well-fitted respirators (N95, KF94, FFP2, or elastomeric) remove ≥ 95 % of 0.3 µm particles and even more below 100 nm because diffusion helps capture the smallest particles.
• When the payoff is largest:
  1. Boarding, taxi, take-off, landing (cabin peaks).
  2. Waiting at the gate or baggage claim—especially when you can smell jet exhaust.
  3. Curbside pickup zones (no filtration at all).
• Fit matters more than model. A loose surgical or cloth mask blocks only ~50 % of UFP; a tight N95 easily exceeds 95 – 98 %.
• If you’re pollution-sensitive (asthma, heart disease, migraine triggers, pregnancy): masking in the terminal and during the first/last 20 min of flight measurably cuts your peak dose.

Practical tips to lower exposure without going full haz-mat

Situation	Low-friction mitigation
Choosing flights	Pick Boeing 787 or A350 when possible—both use electric “bleed-less” packs, eliminating many APU/engine UFP bursts.
Seat selection	Forward cabin rows get fresh recirc fastest; aisle seats avoid direct window-drafts when bleed-air first enters.
Boarding	Be among the last to board and the first to deplane to shorten time in a powered-up but un-pressurised cabin.
In-terminal layovers	Sit away from gate doors, moving walkways and food fryers; look for glassed-off lounges or areas with portable HEPA units.
Tech	Personal PM sensors that measure particle number (e.g., Condensation Particle Counters) can confirm spikes; optical PM₂.₅ meters won’t see UFP.

Bottom line

Even with modern filtration, you’ll still get short, dense bursts of ultrafine particles in terminals and planes—especially at a busy coastal hub like Boston Logan. If you’re health-conscious (or just like stacking the odds), wearing a well-fitted N95 or KF94 in the airport and for the first/last 20 minutes of flight is one of the simplest, evidence-backed ways to drop your effective dose by an order of magnitude.

[AlexKChen]

Should you mask while you’re outside at the airport taxi / ride-share line?

If there’s anywhere on your trip that a respirator actually matters, it’s the curb.
Here’s why:

Micro-environment Typical filtration Dominant sources What the monitors show† Relative exposure rank*

Aircraft cabin (cruise) 100 % of recirc air passes through HEPA (≥99.97 % at 0.3 µm; even better for smaller UFP) Mostly human shedding; occasional “fume-event” spikes 1 – 10 × 10³ particles cm⁻³ LOW
Inside terminal/gate MERV-13 – HEPA HVAC; 6–12 air-changes h⁻¹ Diluted jet exhaust + foot-traffic dust I/O PM₂.₅ ratio ≈ 0.3 (Jakarta T3 study, I/O ≈ 0.33 – 0.54) LOW
Jet-bridge open or ramp break-room Same filters, but door open to ramp Jet/APU exhaust, belt-loaders, catering trucks 15 – 40 × 10³ particles cm⁻³ (Sea-Tac MOV-UP transects) MED
Curbside taxi / ride-app stand No filtration, buildings form a “street canyon” Hundreds of idling taxis, shuttles, buses + drifting jet plume 25 – 80 µg m⁻³ PM₂.₅ & 60 – 150 × 10³ particles cm⁻³ on busy days (Boston Logan & other curb monitors) HIGH
Freeway leaving airport Vehicle A/C cabin filter (often MERV 7-ish) Continuous diesel & gasoline traffic 50 – 120 × 10³ particles cm⁻³ HIGH

*Rank is for ultrafine-particle (UFP) number and traffic-related PM₂.₅ exposure, the two pollutants most strongly linked to cardiopulmonary risk near airports.

†The Logan-Airport study recorded particle-number concentrations (PNC) of 36 000 cm⁻³ at a curb-adjacent roof before COVID; values fell ~50 % when both flight and road traffic collapsed, confirming the curb is driven by ground vehicles + jets together .

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Why the curb is the “dirtiest minute” of your itinerary

1. No filtration barrier. Indoors and on planes you get HEPA-cleaned air; on the curb your lungs are the filter.

2. Engine operating mode is dirty. Taxis, shuttles, and diesel buses sit in high-idle waiting for riders, a regime that maximises particle number and NO₂.

3. Street-canyon effect. Over-hangs and multilevel roadways trap exhaust and slow vertical mixing.

4. Additive jet plume. When the wind lines up with the concourse, UFP from aircraft taxi/idle drifts straight through open doors and across pickup lanes.

5. You linger. Five-to-ten minutes standing still gives almost the same integrated dose as the entire flight in a filtered cabin.

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Practical tips

If you’re pollution-sensitive (asthma, CVD) For everyone

• Put the N95 / KF94 on before you exit baggage claim. Don’t wait until you smell diesel. • Walk a car-length upwind while you order the ride; even 10 m cuts particle number by ~40 %.
• Choose garage pickup if your airport offers it—ventilation is often better than the curb loop. • Keep the rideshare window closed the first few minutes; switch A/C to recirc (“MAX A/C”) until you’re off airport property.
• Skip the curb altogether: take an air-conditioned shuttle to the rental-car or rail station and call a ride there. • Electric-vehicle or hybrid taxis idle far cleaner—worth the extra minute to request if offered.

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Bottom line

Indoors and in the air, HEPA takes care of most ultrafines for you. At the curb nothing does—so that is the one slice of the journey where a good, tight-fitting respirator gives the biggest payoff.

[AlexKChen]

Access Sensor Technologies: Free Product Trial Request Form

[AlexKChen]

NONTHINKING MODEL:

That actually makes a lot of sense. Your Atmotube (depending on the model) is mainly tuned for VOCs, PM1/2.5/10, CO, ozone, and general AQI. A candle like the one in your photo often doesn’t spike those sensors very much, especially compared to cooking or incense. Here’s why:

Why Your Atmotube Shows Little Change

1. Clean-burning wax & wickLe Labo candles are soy-based with cotton wicks (no metal core), so they burn relatively cleanly. That means less soot and fewer VOCs compared to cheap paraffin candles.
2. Particle size mismatchThe ultrafine particles from candle flames are often <100 nm (nanoparticles), which are smaller than what most portable PM2.5 sensors detect well. Atmotube may under-report them because it relies on light scattering, which is less sensitive at that scale.
3. Dilution indoorsA single candle emits a steady but small stream. In a ventilated or even moderate-sized room, concentrations may never reach levels that trigger Atmotube’s alarms, especially compared to a gas stove or frying oil.
4. VOCs are mostly fragrance moleculesYour Atmotube can see total VOCs (TVOCs), but a lot of candle fragrance molecules don’t register strongly in its MOS sensor, especially at low ppb levels.

Candle vs. Other Sources (rough ballpark)

• One scented candle: ~500–1,000 µg/hr of particulates (mostly ultrafine, not PM2.5), ~10–50 µg/hr VOCs.
• Incense stick: 10–50× higher particulate and VOC emissions.
• Gas stove (10 min cooking): spikes NO₂ and PM2.5 far more than candles.
• Frying with oil: huge PM2.5 bursts, orders of magnitude higher than candles.

Bottom line

Your Atmotube not showing much means:

• The candle is relatively “clean.”
• The emissions are either too diluted or too small in size to register strongly.

So in terms of indoor air pollution, a candle like that is minor compared to cooking, smoking, or incense.

Do you want me to give you a quantitative comparison of emissions (like how many candles = one hour of gas cooking, or = one incense stick), so you can benchmark what “small” really means?

Short answer: they overlap a lot mechanistically (oxidative stress → inflammation → tissue injury), but they aren’t identical. On current evidence, ambient ultrafine particles (UFP; <100 nm) have the stronger, better-proven links to human disease, while nanoplastics look harmful in cells/animals and are now turning up in human tissues, but the epidemiology is newer. Whether one is “worse” depends on dose, chemistry, and route of exposure.

Where they’re similar

• ROS & mitochondrial stress → inflammation. Both UFP and nanoplastics raise reactive oxygen species, impair mitochondria, and induce inflammatory signaling that can progress to endothelial dysfunction and thrombosis.
• Barrier crossing & organ translocation. Nanoscale particles can cross biological barriers; UFPs can even reach the brain via the olfactory nerve, and nanoplastics can traverse the blood–brain barrier in models.
• Innate-immune activation. Particulates can trigger inflammasome pathways (e.g., NLRP3), though the strength of activation varies by particle type/surface.

Where they differ

• Chemistry & reactivity.
  • UFP from combustion carry metals and PAHs that catalyze redox cycling—often making them highly bioactive per unit mass. This likely underlies their consistent associations with cardiovascular events and mortality.
  • Nanoplastics are polymeric; the polymer itself is less redox-active, but additives, monomers, and surface oxidation can cause lysosomal damage and endocrine/interference effects; results vary widely with how “model” particles are made.
• Human evidence base.
  • UFP: Decades of mechanistic and population data link exposure to higher risks of heart disease, stroke, BP changes, autonomic imbalance, and systemic inflammation.
  • Nanoplastics: Rapidly emerging. A 2024 NEJM study found micro/nanoplastics in human carotid plaques, with a markedly higher risk of MI/stroke/death over ~34 months when plastics were present, but causality and exposure–response still need confirmation.
• Exposure context.
  • UFP spikes come from traffic, cooking, and candles—especially “stressed” burning—often invisible to mass-based consumer sensors. Small studies show candle/cooking UFP can provoke inflammatory biomarker changes in sensitive people.
  • Nanoplastics exposure is mainly ingestion/inhalation of fragmented plastics and fibers; internal doses and dominant routes are still being pinned down in humans.

Bottom line

• “Basically the same?” Mechanistically, yes (ROS → inflammation → tissue injury), but UFPs are typically more chemically reactive and are more clearly tied to human outcomes today.
• “Even worse?” In real-world air, UFPs often pose the more immediate risk (dose peaks, proven cardio-cerebrovascular links). Nanoplastics may add chronic, biochemical, and endocrine-disrupting risks, but the human causal picture is earlier and more heterogeneous.

Practical minimization (fast wins)

• Cut indoor combustion peaks (simmering, ventilation on high, lids; avoid long candle burns or burn by an open window).
• Use a good HEPA purifier near sources (diffusion makes HEPA surprisingly efficient for UFP despite the 0.3 µm spec) and activated carbon for VOCs; keep filters fresh. (General consensus from air-filtration standards; mechanism via Brownian diffusion.)
• Outdoors: time traffic-adjacent exercise for off-peak hours; prefer routes set back from major roads.

If you want, tell me your common sources (traffic, incense/candles, frying) and I’ll give you a targeted plan to knock down the biggest UFP spikes first.

[AlexKChen]

[AlexKChen]

You’re not wrong: living near big roads correlates with higher dementia risk. But “within 600 m” is a mushy generalization. The best data say the risk rises most sharply really close to the road and drops off fast with distance, and the Bay Area’s geography, winds, and diesel rules bend the curve a bit.

Here’s the clean version without the hand-waving:

• What the strongest studies show
  • A huge Ontario cohort (6.6M people) found higher dementia incidence for homes close to major roads, with the bump clearest within ~50–200 m and fading by ~300 m.
  • Meta-analyses since then generally link PM2.5, NO₂, and black carbon/soot to higher dementia risk (small per-unit increases, but consistent).
  • It’s not unanimous: a 2024 cohort tracking ultrafines/NO₂/BC found no dementia signal, so mixture, levels, and context matter. Translation: it’s not just “any freeway anywhere.”
• Why the Bay Area can look different from, say, Ohio
  • Diesel controls are aggressive. California’s diesel rules and truck retrofits slashed diesel PM statewide (targeting ~85% reduction vs 2000 levels). Heavy-duty trucks are a small slice of vehicles but still dominate NOx and diesel PM, so rules matter.
  • Coastal wind + marine layer = more dilution most days. The prevailing WNW sea-breeze and frequent mixing shear the plume and push it bayward. That tends to flatten the near-road PM2.5 bump compared with calmer inland metros. Not always, but often.
  • The nastiest diesel hotspots are across the estuary. Hyper-local mapping in Oakland shows big spikes in NO₂/BC/ultrafines near I-880/Port corridors and West Oakland streets. SoMa and the I-80/101 knot are bad for traffic, but the diesel signature is usually stronger on the Oakland side.
  • PM2.5 near roads is underwhelming; gases/soot/ultrafines aren’t. Across the U.S. near-road network, PM2.5 at curbside is often only ~0.1–2 µg/m³ above background (or even lower than urban background), while NO₂ shows steep dropoffs within 100–200 m. If you only watch PM2.5, you’ll miss most of the freeway signature.
• So does living near Bay Area freeways still matter for brain risk?
  • The weight of evidence says long-term exposure to traffic-related pollution contributes to dementia risk, especially via PM2.5/soot/NO₂. The absolute risk bump in SF can be smaller than in diesel-heavy, stagnant-air regions, but it’s not zero.
  • Also, noise is its own risk factor for cognitive decline and can co-travel with traffic. Some reviews find independent links between chronic noise and ADRD.
  • Wildfire and winter wood smoke dominate many Bay Area PM2.5 peaks, which muddy the “freeway vs dementia” picture unless you separate sources. Policy folks are already shifting thresholds because of that broader burden.
• Practical takeaways for the Bay
  • If you’re choosing housing near I-80/101, prioritize distance first 50–200 m, upwind orientation (west/northwest upwind sides are often cleaner), higher floors, and buildings with MERV-13/HEPA in bedrooms. This targets the pollutants most tied to dementia risk rather than just PM2.5 mass.
  • For daily exposure, route choices matter more than vibes: block-by-block maps show 5–8× differences at specific intersections. Favor interior streets and green buffers; dodge port-bound truck corridors.
  • Track NO₂/BC/ultrafines when you can; a clean PM2.5 read near a freeway isn’t a free pass.

Bottom line: the freeway–dementia link is real in the literature, but in the Bay it’s moderated by wind, strict diesel policy, and where exactly you stand relative to truck routes. Don’t panic-sell your lease; just avoid the first 100–200 meters, filter your bedroom air, and stop trusting PM2.5 alone to tell you the whole story.

[AlexKChen]

Tire and road wear particles account for approximately 28% of global microplastic contamination. Nespsustainable Every year 1.7 billion new tires are produced worldwide, and during use an average car tire loses about 1.5 kg in mass, forming millions of tire wear particles. Frontiers Per capita emissions range from 0.23 to 4.7 kg/year, with a global average of 0.81 kg/year PubMed Central — and this is a source that electrification does nothing to fix, since EVs are actually heavier and produce more tire wear.

And you’re right that the chemistry matters enormously. TWPs and crumb rubber consist mainly of synthetic styrene-butadiene rubber in a size range of 10 nm to several millimeters, and constitute their own class of microplastics, where both rubber particles and their leachates may induce toxic effects. Frontiers Simulation results indicated styrene-butadiene rubber had the most significant toxic effect on zebrafish among the tire rubber polymers tested. ScienceDirect

The key distinction you’re drawing: PE is relatively biologically inert. It’s bad because of particle effects (inflammation, physical disruption) and because it acts as a vector for adsorbed contaminants. But SBR is intrinsically toxic. Styrene is classified as a Group 2A probable human carcinogen by IARC. It’s a known neurotoxin, endocrine disruptor, and causes oxidative stress. So when tire wear particles shed styrene monomers and oligomers as they degrade, you’re getting continuous low-dose exposure to a carcinogen delivered via microparticle — which is arguably the worst possible delivery mechanism because the particles can cross biological barriers that dissolved styrene can’t.

And it gets worse. SBR tire particles don’t just leach styrene. They also carry:

• 6PPD-quinone (the tire antioxidant transformation product that’s been killing coho salmon in urban streams — incredibly potent, LC50 in the low µg/L range)
• PAHs (polycyclic aromatic hydrocarbons, many of which are carcinogenic)
• Benzothiazoles (used as vulcanization accelerators)
• Phthalate plasticizers
• Heavy metals (zinc especially, from zinc oxide used in vulcanization)

Elevated SBR to natural rubber ratios in fine PM10 particles compared to coarser fractions suggest that passenger car tires, which contain more SBR, contribute disproportionately to the smallest, most inhalable tire wear particles. PubMed So the most toxic rubber composition preferentially generates the most bioavailable particle sizes. That’s an ugly combination.

Non-exhaust emissions are comparable in toxicity to exhaust emissions and wood combustion, yet there’s been almost no regulatory attention — the EU’s Euro 7 regulation introduced worldwide non-exhaust emission limits for the first time only recently. PubMed Central

This is also why your “live player” framework is interesting here. The tire industry is massive, consolidated, and has strong incentives to keep the current SBR formulation. Natural rubber alternatives exist but have cost and supply chain constraints. Who’s actually pushing to reformulate? Where are the live players in this space? The regulatory landscape is almost nonexistent compared to how well-understood the hazard is.