Oakwell
Pillar 06 · Environment

Air quality — the invisible input.

You take roughly 22,000 breaths a day, ~90% of them indoors. Indoor air is routinely 2–5× more polluted than outdoor air. Cleaning it up is one of the cheapest, most underrated health upgrades available.

Why indoor air matters

Long-term exposure to fine particulate matter (PM2.5) is linked to cardiovascular disease, stroke, lung cancer, asthma, and accelerated cognitive decline. Volatile organic compounds (VOCs) from new furniture, paint, cleaning products, and "fragrances" irritate airways and disrupt hormones. Combustion sources — gas stoves especially — release nitrogen dioxide that's been linked to childhood asthma.

~90%of time spent indoors by average adult
2–5×indoor pollution vs outdoor
PM2.5small enough to enter the bloodstream

The main offenders

  • PM2.5 — cooking (especially gas), candles, wildfire smoke, dust.
  • VOCs — paint, varnish, particleboard furniture, scented candles, plug-ins, cleaning sprays, dry-cleaned clothes.
  • NO₂ & CO — gas stoves, gas furnaces, attached garages.
  • Mold — bathrooms, basements, crawlspaces, anywhere with chronic moisture.
  • Radon — naturally occurring radioactive gas; the #2 cause of lung cancer in the US.
  • CO₂ — at high indoor levels (>1,000 ppm) it impairs cognition.

Measure it

You can't manage what you don't measure. Pick up:

  • A PM2.5/CO₂ monitor (Aranet4, Awair, IQAir AirVisual)
  • A radon test — short-term kits are ~$15; long-term digital monitors give a truer picture
  • A CO alarm on every level of the home (this is also a legal requirement in many places)

Filter it

True HEPA filters capture 99.97% of particles 0.3 microns and larger. Activated carbon handles VOCs and odors. The number that matters most is CADR (clean air delivery rate) relative to your room size — bigger room, bigger machine.

SizeWhat to buy
Small bedroomLevoit Core 300 / Coway AP-1512HH
Living room / open planCoway Airmega 400 / IQAir HealthPro
Whole houseUpgrade HVAC to MERV 13 filters
DIY / wildfireCorsi-Rosenthal box ($60 in parts, exceptional CADR)

Ventilate

  • Open windows daily when outdoor AQI is good — even 10 minutes helps.
  • Always run the range hood when cooking (vented outside, on high).
  • Run bathroom fans during and 20 minutes after every shower.
  • Consider an ERV/HRV if you're in a tight, modern home.

Reduce sources

  • Take shoes off at the door.
  • Choose low-VOC paint, finishes, and solid-wood (not particleboard) furniture when you can.
  • Stop burning candles and incense indoors — or limit to outdoors.
  • Use unscented or fragrance-free cleaning products.
  • If you cook on gas, prioritize the range hood, or plan to switch to induction at next replacement.

Mold & moisture

Keep indoor humidity 30–50%. Fix leaks immediately. If you smell mustiness or see staining, get it tested before it gets worse — moisture problems compound fast.

Recommended products

Monitor

Aranet4 Home

Battery CO₂ monitor; the number changes how you think about ventilation.

Filter

Coway Airmega series

Reliable HEPA + carbon, sane filter prices.

Radon

Airthings Wave Radon

Battery-powered, no subscription, app history.

DIY

Corsi-Rosenthal box

4 MERV-13 filters + a box fan = cheapest serious purifier you can build.

Quick-win checklist

  • Run a HEPA purifier in the bedroom 24/7.
  • Range hood on, every cook, every time.
  • Test for radon this season.
  • Open windows when outdoor AQI is good.
  • Take shoes off at the door.