Real-Time Air Quality Index
Live AQI readings come from the WAQI network — the largest aggregator of air quality monitoring stations globally, covering 20,000+ stations. Your location is matched to the nearest station and updated in real time.
PM2.5
Fine particles ≤2.5µm — deepest lung penetration
PM10
Coarse particles ≤10µm — dust, pollen, mould
O₃
Ground-level ozone — sunlight + pollutants
NO₂
Nitrogen dioxide — traffic & combustion
SO₂
Sulphur dioxide — industry & power plants
CO
Carbon monoxide — incomplete combustion
AQI Scale (US EPA)
Weather Data
Weather is fetched from YR (met.no) — the Norwegian Meteorological Institute — the same primary source used in our iOS app. YR provides highly accurate temperature, humidity, wind, and condition data, especially for European locations.
UV index (cloud-adjusted) and visibility are supplemented from Open-Meteo, since YR's compact API doesn't include those fields. Both are fetched in parallel for every page load.
Indoor Air Quality Estimation
There are no widespread indoor monitoring networks — so Atmos estimates indoor air quality from first principles using a physics-based infiltration model and your questionnaire answers about your home.
PM2.5 & PM10
(outdoor × infiltration + sources) × purifierBuilding tightness, ventilation type, gas cooking, smoking, pets
O₃ (Ozone)
outdoor × 0.15Ozone reacts rapidly with indoor surfaces
NO₂
outdoor × 0.50 + gas stove sourceGas cooking is the dominant indoor NO₂ source
CO
outdoor × 0.80 + gas stove + smokingIncomplete combustion is the main indoor CO source
The final indoor AQI is the maximum EPA sub-index across all pollutants. A confidence score (0.50–0.85) reflects how much data your questionnaire provided.
Personal Exposure Tracking
Your daily exposure score is a time-weighted average of the air you actually breathe — not just what's outside your window.
Formula
score = (outdoor_AQI × outdoor_hours + indoor_AQI × indoor_hours) ÷ 24Log how many hours you spent outdoors each day. Atmos pairs that with your outdoor AQI and estimated indoor AQI to compute a single daily score. A 30-day history with weekly averages and trend arrows lets you track what's improving or worsening — useful for managing asthma, allergies, or any respiratory condition.