AirCheck
Track air quality (AQI) in real-time across major cities worldwide. Every breath. Everywhere.
250
Tracked now
500
Strongest (AQI)
Open-Meteo (CAMS)
Source
Right now
All observations →- 20Wellington — AQI 20Wellington, New Zealand · Good · 20 AQI
- 10Auckland — AQI 10Auckland, New Zealand · Good · 10 AQI
- 20Perth — AQI 20Perth, Australia · Good · 20 AQI
- 30Brisbane — AQI 30Brisbane, Australia · Good · 30 AQI
- 40Melbourne — AQI 40Melbourne, Australia · Good · 40 AQI
- 22Sydney — AQI 22Sydney, Australia · Good · 22 AQI
- 53Almaty — AQI 53Almaty, Kazakhstan · Moderate · 53 AQI
- 23Tashkent — AQI 23Tashkent, Uzbekistan · Good · 23 AQI
- 46Yangon — AQI 46Yangon, Myanmar · Good · 46 AQI
- 40Colombo — AQI 40Colombo, Sri Lanka · Good · 40 AQI
Scale (AQI)
GoodModerateUnhealthy (sensitive)UnhealthyVery UnhealthyHazardous
Learn the basics
Air quality describes how clean or polluted the air is, and what that means for your health. The single number you usually see is the Air Quality Index (AQI) — a 0–500 scale that converts the measured concentration of several pollutants into one easy-to-read value with a color, from green “Good” to maroon “Hazardous”.
AirCheck pulls live readings from thousands of ground sensor stations worldwide, normalizes each pollutant onto the AQI scale, and shows you the worst (highest) pollutant for every place — because on any given day a city’s air is only as healthy as its dominant pollutant.
How the Air Quality Index worksWhy one pollutant’s concentration becomes a 0–500 number, the six categories, and how the reported AQI is the worst pollutant, not an average.The pollutants that drive the indexPM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide — what each is, where it comes from, and why it matters.What polluted air does to the bodyShort- and long-term effects, and why children, older adults, pregnant people and those with heart or lung conditions are most at risk.Protecting yourself on bad-air daysPractical steps by AQI category — timing outdoor activity, filtering indoor air, masks that actually work, and when smoke changes the rules.Where the numbers come fromReference-grade monitors vs. low-cost sensors, why two nearby readings can differ, and how AirCheck normalizes them.