What's in the air

One entry for every number the app can show: what the number measures, what it does to breathing, the span it covers, and where it came from.

• Fine particles PM2.5 · µg/m³ · 24h average
• Ozone O₃ · µg/m³ · 8h average
• SO₂ SO₂ · µg/m³ · the hour
• Coarse particles PM10 − PM2.5 · µg/m³ · 24h average
• Smoke NOAA HMS · light, medium, heavy · the hour
• Mold spores/m³ · highest of the last 3 counts
• Dry-spore conditions weather proxy · 0–5 · each hour, in season
• Tree pollen Google pollen · 0–5 · the day
• Grass pollen Google pollen · 0–5 · highest of 3 days
• Weed pollen Google pollen · 0–5 · the day
• Dew point °F or °C · the hour
• Sick

The photographs come from Wikimedia Commons, public domain or CC BY / CC BY-SA. Each entry carries its own credit.

Breathing Index is a breathing lens on public air data — not medical advice. Trust your symptoms and your asthma action plan over anything on this screen.

Breathing Index is a free logbook for this. You rate your breathing from 1 to 4, it stores every one of these readings alongside the rating, and over time it marks which of them your own days say affect you. What this is · Open it