Definition of Air pollution index

The Air Pollution Index (API) is a simple and generalized way to describe the air quality in Hong Kong and Malaysia. It is in the form of an integer within 0 and 500, which is calculated from several sets of air pollution data.

The Air Quality Index (AQI) is a standardized indicator of the air quality in a given location. It measures mainly ground-level ozone and particulates (except the pollen count), but may also include sulphur dioxide, and nitrogen dioxide. Various agencies around the world measure such indices, though definitions may change between places.