PM2.5: the fine stuff
Particles smaller than 2.5 micrometers slip past your nose, lodge deep in the lungs, and cross into the bloodstream. They are the single most-studied air pollutant.
Articles tagged "Health"
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Ultrafine particles: what the sensor cannot see directly
Below 100 nanometers, particles get small enough to cross from lungs into bloodstream. The SEN66 sees PM₁ but stops there.
Wildfire smoke: what is in it, what to do
A complex aerosol dominated by PM₂.₅, with VOCs, NOx, and dozens of trace species. Indoors, the right response is to seal up and filter, not ventilate.
Mold: Terrestream is not a mold detector
Terrestream does not detect mold or count spores. It reports temperature, pressure, and relative humidity - conditions that are sometimes associated with mold. Mold can also grow in conditions and places the sensor never sees.
Dust mites: the bedroom ecosystem you cannot see
House dust mites need humidity to reproduce and warmth to thrive. The sensor reads both. Allergen is in the air whenever the bed gets disturbed.
Pet dander: what the PM₁₀ trace shows
Cat allergen is sticky and stays airborne for hours. Dog allergen settles faster. Both show up in PM₁₀ when pets move through a room.
Children: higher exposure, more vulnerable lungs
Kids breathe 50% more air per kg than adults, spend more time indoors, and have lungs that are still developing.
Asthma triggers: the indoor list
Asthma is the most common chronic disease in children. Most of its triggers are things the sensor sees.
Cardiovascular disease and PM₂.₅
PM₂.₅ kills more people through hearts than through lungs. The mechanism is systemic inflammation, oxidative stress, and direct arterial effects.
UV index: sunburn risk in a single number
The UV index condenses solar ultraviolet intensity into a 0–11+ scale. Above 6, take precautions. Above 8, every minute counts.
Pollen species: the six that matter most
Alder, birch, grass, mugwort, olive, ragweed. Open-Meteo reports each; the seasons are very different.
Vaping, smoking, and cannabis
Combustion and aerosolization indoors. Tobacco smoke, cannabis smoke, and vape aerosol all show on the sensor; the health profiles differ significantly.
Productivity and air quality
Decisions get worse, errors rise, and absences increase as air quality drops. The literature quantifies it; the dashboard surfaces it.
Sick building syndrome
A cluster of complaints, no single identifiable cause. The diagnosis has fallen out of fashion; the underlying problems haven't.
Classroom CO₂ and learning
Test scores correlate with ventilation rates. Attendance correlates with ventilation rates. The literature is unusually consistent.
Cumulative vs acute exposure
A bad afternoon and a bad decade are different problems. The literature is clear about which matters more for what.
Older adults and air quality
Cardiovascular sensitivity, frailty, medication interactions, and time-indoors all shift with age. The thresholds shift too.
Allergen sources, an overview
Mold, dust mites, pet dander, pollen, mold spores. Most household allergen exposure is one of these five. The dashboard groups them as a family.
COPD and air quality: tighter margins than asthma
Chronic obstructive pulmonary disease affects 16 million US adults. PM2.5 sensitivity is higher than asthma, exacerbations are more dangerous, and indoor recovery matters more.
Migraines and air quality: triggers the dashboard can show
VOC bursts, pressure drops, low CO₂-induced drowsiness preceding a migraine: the dashboard can document triggers a person knows but cannot prove.
Sleep apnea and air quality: humidity, mites, and overnight CO₂
OSA outcomes interact with bedroom-overnight conditions. The right humidity, low dust-mite allergen, and adequate ventilation can improve CPAP comfort and reduce AHI.
Mental health and air quality: an emerging literature
Recent research links chronic PM2.5, VOCs, and indoor CO₂ to depression, anxiety, and cognitive performance. The data is suggestive, not yet prescriptive.
Formaldehyde (HCHO): why Terrestream does not measure it
Formaldehyde (HCHO) is the most asked-about specific VOC. The Terrestream SEN66 does not measure, report, or detect it - do not use the device to check for formaldehyde. If you suspect it, get a dedicated test or professional advice.
Benzene: why Terrestream does not measure it
Benzene (C₆H₆) is IARC Group 1, present in vape aerosol, traffic, attached garages, and wildfire smoke. The Terrestream SEN66 does not measure, report, or detect it - do not use the device to check for benzene. Only speciated lab testing can identify it; if you suspect benzene, seek professional testing or advice.
Pets and air quality: birds, dogs, cats, and the rest
Pets share your indoor air. Birds are uniquely sensitive (the "canary in a coal mine" is literal); dogs and cats have their own profiles.
Ozone: an outdoor pollutant we read but cannot make
Ground-level ozone is the most consequential summertime air pollutant in much of North America. The sensor cannot detect it directly; the dashboard pulls it from Open-Meteo.
CO₂ as an airborne-pathogen proxy: what the ratio actually tells you
CO₂ does not measure pathogens. But CO₂ and exhaled pathogen droplets share a source (occupants) and a sink (ventilation), so the indoor-to-outdoor CO₂ ratio tracks the fraction of air in the room that other people have already breathed. This is why the Aranet model was widely adopted for ventilation monitoring during the pandemic.
SBS vs BRI vs MCS: three terms that are not interchangeable
"Sick building syndrome" gets used to mean three different things, and the difference matters because each leads to a different diagnostic path. Here is the disambiguation, with the room-by-room signatures the dashboard can and cannot help find.
Infants and indoor air quality
A newborn breathes faster, has smaller airways, and spends almost every hour of every day in the same indoor environment. The standard adult guidelines were not written with that physiology in mind.
Breathe Better. Live Smarter.
Turn air-quality knowledge into action.
One sensor. Twelve signals. Indoor readings connected to outdoor context and plain-English recommendations. Everything you just read can be measured live in your own home.
$249 USD one-time
Buy Terrestream Explore the sensor- No subscription required
- 30-day returns
- 1-year limited warranty
- Fast shipping via FedEx
Six sensors. Twelve signals.
Built on genuine Sensirion, Bosch, and Texas Instruments sensors.
- CO₂
- IAQ
- VOC
- NOₓ
- PM1
- PM2.5
- PM4
- PM10
- Temperature
- Humidity
- Pressure
- Light
Included
- In the box: the sensor, USB-C cable, power adapter, and printed field guide
- Dashboard and mobile app included
- Privacy-first air data
Works with
- Home Assistant
- MQTT
Home Assistant
MQTT