September 2nd 2016: Please note that the offical Air Quality Index (AQI) for Malaysia from DoE is only based on PM10, and not PM2.5 (read mode). The Air Quality Index is moreover reported as the average of the past 24 hours, and not of the previous hour (read mode).
This means that during the period of Haze, where the Air Quality Index can deteriorate significantly and fast, the published AQI value is most likely lower than the actual Air Quality (i.e. the air pollution is most likely higher than what is published). We are trying to engage the DoE to fix this issue and, to start with, provide API readings without 24 hours averaging, which will defintely help to better reflect the actual conditions in case of haze. Note that DoE is indeed providing readings for each hour, but each hourly value is the average of the past 24 values/hours, while no averaging should be used (data should be reported as it monitored, without averaging; this is common practice).
Air Quality Data provided by the Malaysian Department of the Environment (Jabatan Alam Sekitar).