Index of air quality in the world's major cities: January 04

Daily air quality index of some of the world's major cities on January 04, using data from AirNow, CITEAIR, and the American Embassy in Beijing.


Average 03/01/2011 Average 04/01/2011

London (UK)

  Good                                                                   Good                                                        
Madrid (Spain) Moderate NA

Paris (France)

Good Good

Brussels (Belgium)  

Good Good

Berlin (Germany )

Good Good

Prague (Czech Republic)

Good Good

Zurich (Switzerland)

Good Good

Beijing (China)  


Beijing - US embassy stats

Very unhealthy Unhealthy for sensitive groups

Shanghai (China)  

NA Good

Hong Kong (China)

Moderate Good

Brunei (Brunei)

Good Good

New York (USA)  

Good Moderate

San Francisco (USA)

Moderate Moderate

Mexico City (Mexico )

Good Moderate

Montreal (Canada)

Good Good

Toronto (Canada)

Good Good

New Delhi (India)

Unhealthy Hazardous

Sydney (Australia)

Good NA

The Air Quality Index (AQI) or Air Pollution Index (API) measures the parts of pollutant in a specified volume of air. The lower the AQI the fewer particles of pollution are in the air. For a more detailed explanation see

All results are color-coded following the American AQI standard shown below. For all countries outside of Europe, the US and Canada, that region's definition of AQI terms has been accepted.


Air Quality






Unhealthy for sensitive groups




Very Unhealthy




Data: Data relating to Europe, the US and Canada is taken from CITEAIR - Common Information to European Air ( /; data concerning China is taken from both official Chinese government sources and the US Embassy's automated air index Twitter account. For all countries the data displayed falls within either that country's definition of the level of air quality or the international AQI index. Data for all European, US and Canadian cities refers to background, not roadside, levels of air quality.

All data was collected at 9:00am GMT on January 04.