Air Quality Today
Live AQI readings for major world cities · Updated every 30 min · As of Tue, 17 Mar 2026 23:18:04 GMT
Live AQI — Major Cities
AQI Scale — What Does Today's Number Mean?
| AQI Range | Category | What It Means Today |
|---|---|---|
| 0–50 | Good | Air quality is satisfactory. No precautions needed. Fine for all outdoor activities. |
| 51–100 | Moderate | Acceptable. Unusually sensitive people may experience minor effects. Most can enjoy outdoor activities normally. |
| 101–150 | Unhealthy for Sensitive Groups | Sensitive groups (asthma, heart/lung disease, children, elderly) should reduce prolonged outdoor exertion. |
| 151–200 | Unhealthy | Everyone may begin to experience effects. Limit prolonged outdoor exertion; sensitive groups should avoid it. |
| 201–300 | Very Unhealthy | Health alert. Everyone should avoid prolonged outdoor exertion. Sensitive groups should stay indoors. |
| 301+ | Hazardous | Emergency conditions. Everyone should stay indoors, keep windows closed, use air purifiers if possible. |
Check Your City's Air Quality Today
Don't see your city above? Search any city worldwide for live AQI data.
Search Any City →Frequently Asked Questions
Is the air quality bad today?
Air quality varies by city and by the hour. Use the live AQI grid on this page or search your specific city for a real-time reading. If your city shows AQI above 100, consider reducing prolonged outdoor activity, especially strenuous exercise. AQI above 150 is Unhealthy for everyone.
What time of day is air quality usually worst?
Air quality is typically worst in the early morning (6–9 AM) during rush hour and again in the evening (5–8 PM). In many cities, a midday ozone peak occurs in summer from sunlight reacting with traffic emissions. The cleanest time is usually mid-morning or early afternoon on sunny days when mixing height is greatest.
How current is today's AQI data?
The readings on this page are sourced from the WAQI network and revalidated every 30 minutes. Most monitoring stations report every hour. If a station is offline, you may see the last available reading, which could be several hours old.
What does today's AQI mean for my health?
AQI 0–50 (Good) — air is clean, outdoor activity is fine for all. AQI 51–100 (Moderate) — acceptable for most, but unusually sensitive individuals may experience discomfort. AQI 101–150 — Unhealthy for Sensitive Groups; reduce prolonged outdoor exertion if you have asthma, heart disease, or lung conditions. AQI 151–200 — Unhealthy for everyone; limit outdoor exercise. AQI 200+ — Very Unhealthy or Hazardous; stay indoors.
Why does AQI differ between different apps?
Different apps may use different monitoring stations (different locations within a city), different averaging periods (1-hour vs 24-hour), or different AQI calculation standards (US EPA, European CAQI, Chinese AQI). This site uses the US EPA AQI standard and WAQI network data.