Live air quality
Hover or tap a city for live PM2.5, temperature and humidity.
How to read it
PM2.5 comes from Open-Meteo's air-quality API (CAMS model, hourly). The AQI shown is the US EPA category derived from that PM2.5 reading. Temperature and humidity come from Open-Meteo's forecast API. Both refresh every 30 minutes via a GitHub Actions cron that writes frontend/data/sea-live-air.json. Colour is by PM2.5 by default: green good, yellow moderate, orange unhealthy, red hazardous. Switch the colour mode in the top right to recolour by temperature or humidity.
Why PM2.5 specifically
PM2.5 is the fraction of airborne particulate matter small enough to slip past the nasal filter and lodge deep in the lungs and bloodstream. Of every air-quality metric collected by the major networks, it has the strongest link to chronic disease outcomes, so it is the headline number behind every AQI app. A peak haze-week reading of 200 µg/m³ (hazardous) in Chiang Mai or Hanoi is unpleasant. A multi-year average of 30 µg/m³ is what shapes your long-term health.
More detail per country
For a closer look at any specific country see Thailand, Vietnam, Indonesia, Philippines, Malaysia, Cambodia, Laos, Bali.