Air Quality Index Hub
Understanding air quality indices from around the world and what they mean for your health
What is the Air Quality Index?
The Air Quality Index (AQI) is a standardized indicator that tells you how clean or polluted your air is, and what associated health effects might be a concern.
Easy to Understand
Converts complex air quality data into simple numbers and colors
Health-Focused
Provides health advice based on current pollution levels
Real-Time Updates
Updated regularly to reflect current air quality conditions
US EPA AQI Levels
Understanding the six categories of air quality
Good
Air quality is satisfactory, and air pollution poses little or no risk.
💡 Enjoy outdoor activities!
Moderate
Air quality is acceptable. However, there may be a risk for some people.
💡 Sensitive individuals should consider limiting prolonged outdoor exertion.
Unhealthy for Sensitive Groups
Members of sensitive groups may experience health effects.
💡 Children, elderly, and people with respiratory conditions should limit outdoor activities.
Unhealthy
Some members of the general public may experience health effects.
💡 Everyone should limit prolonged outdoor exertion.
Very Unhealthy
Health alert: The risk of health effects is increased for everyone.
💡 Avoid outdoor activities. Keep windows closed.
Hazardous
Health warning of emergency conditions: everyone is more likely to be affected.
💡 Stay indoors and keep activity levels low. Wear a mask if you must go outside.
AQI Systems Around the World
Different countries use different methodologies to calculate and communicate air quality
UrbanReflex NGSI-LD
UrbanReflex AQI
Real-time air quality data from UrbanReflex NGSI-LD Context Broker with standardized measurements.
Vietnam
Vietnam AQI
Vietnam's national air quality standard based on major pollutants.
United States
US EPA AQI
The US Environmental Protection Agency AQI is a standardized indicator of air quality.
China
China AQI
Chinese Air Quality Index based on 6 major pollutants.
India
AQI (National Air Quality Index)
India's national AQI launched in 2014 for major cities.
European Union
CAQI (Common Air Quality Index)
European Air Quality Index used across EU member states.
Common Air Pollutants
Learn about the pollutants measured in air quality indices
PM2.5
Fine Particulate Matter
Particles smaller than 2.5 micrometers that can penetrate deep into lungs
Vehicle emissions, industrial processes, wildfires
Respiratory and cardiovascular problems
PM10
Coarse Particulate Matter
Particles smaller than 10 micrometers
Dust, pollen, mold, construction
Respiratory irritation, reduced lung function
O3
Ozone
Ground-level ozone formed by chemical reactions
Vehicle emissions + sunlight, industrial emissions
Breathing problems, asthma aggravation
NO2
Nitrogen Dioxide
Reddish-brown gas with pungent odor
Vehicle emissions, power plants
Respiratory inflammation, reduced immunity
SO2
Sulfur Dioxide
Colorless gas with sharp odor
Coal and oil combustion, metal smelting
Breathing difficulties, especially for asthmatics
CO
Carbon Monoxide
Colorless, odorless gas
Vehicle emissions, incomplete combustion
Reduces oxygen delivery to organs
Check Your Local Air Quality
Explore real-time air quality data from monitoring stations worldwide
Explore Air Quality Map