The Dyson Global Connected Air Quality Data project analyses more than half a trillion data points to paint a picture of the air quality in real homes around the world, understand user behaviors and compare indoor and outdoor air quality. The indoor air quality studied is based on the location of Dyson purifiers in homes and as such is not nationally representative.

Indoor air quality data is taken from Dyson purifiers that are connected to the MyDyson app and in monitoring-only mode – that is, not actively purifying the space. Whilst this reduces the sample size for the calculation, Dyson data scientists can be confident that it is an accurate representation of air quality in real homes, without the impact of Dyson purifiers actively cleaning the air.

Outdoor air quality data is sourced primarily from OpenAQ, and from the World Air Quality Project in Shenzhen, Fukuoka, Osaka, Amsterdam and Taipei.

Countries studied (39): Australia, Austria, Belgium, Canada, China, Czechia, Denmark, Finland, France, Germany, Greece, Hungary, India, Indonesia, Ireland, Israel, Italy, Japan, Malaysia, Mexico, Netherlands, New Zealand, Norway, Philippines, Poland, Portugal, Romania, Saudi Arabia, Singapore, South Korea, Spain, Sweden, Switzerland, Thailand, Turkey, U.A.E., U.K., U.S.A., Vietnam

Cities studied (44): Amsterdam, Bangkok, Beijing, Berlin, Bristol, Brussels, Busan, Chicago, Cologne, Copenhagen, Delhi, Dubai, Dublin, Fukuoka, Hanoi, Hong Kong SAR, Istanbul, Jakarta, Kuala Lumpur, London, Los Angeles, Lyon, Madrid, Manchester, Manila, Marseille, Melbourne, Mexico City, Milan, Mumbai, Munich, New York, Osaka, Paris, Rome, Seoul, Shanghai, Shenzhen, Stockholm, Sydney, Taipei, Tokyo, Toronto, Vienna.