The Air Quality application shows the real-Time Air Quality Index (AQI) for more than 60 countries in the World (Mainland China, Hong Kong, Taiwan, Singapore, Vietnam, India, Malaysia, Thailand,South Korea and Japan....)The Air Quality data sources varies depending on the cities:- The US Embassy PM2.5 data is used for Shanghai, Beijing, Chengdu and Guangzhou. - The China Ministry Environment Pollution Departement PM10 data is used for all other cities in China. - For Hong Kong and Taiwan, the respective Environment agencies PM2.5 data is used. - For Singapore, the Singapore National Environment Agency PM2.5 data is used. - For the other countries, please refer to our website (aqicn.org)The overall AQI, PM2.5 and PM10 measurements are updated every hour.oOoIn order to install the widget, you need to insert it on the homescreen:- If you are using Android 4.0 (Ice Cream sandwich), select the "All Apps" icon (usually on the top-right corner), then the widget tab, and click on the "Air Quality" widget.- If you are using any other version below 4.0, you need to long-press in an empty area on the default home screen and select "Widgets", and then "Air Quality".oOoFor more information, you can consult the website aqicn.org.