The air pollution thread

#1

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)

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

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[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?]

All my air pollution posts
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#5

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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.

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#8

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

#9

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.

#10

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-Âł, but brief spikes can exceed 20 000 particles cm-Âł when a jet bridge is open or service vehicles idle nearby.
    • Cabin while cruising: a few hundred to a few thousand particles cm-Âł (well below subway or highway levels).
    • Cabin during boarding, taxi, take-off or landing: short peaks of 30 000–100 000 particles cm-Âł 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-Âł 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 ”m; 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-Âł 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 ”m 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.

#11

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 ”m; even better for smaller UFP) Mostly human shedding; occasional “fume-event” spikes 1 – 10 × 10Âł particles cm⁻³ LOW
Inside terminal/gate MERV-13 – HEPA HVAC; 6–12 air-changes h⁻Âč 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 × 10Âł 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 ”g m⁻³ PM₂.₅ & 60 – 150 × 10Âł 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 × 10Âł 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 .

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.

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.

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.