[1] The Environmental Protection Department (EPD) was created in 1986 to co-ordinate and carry out pollution prevention and control activities.

Between 1986 and 31 March 2005 it functioned mainly as an executive department enforcing environmental laws and implementing environmental policies, the latter having been determined by the relevant policy bureau, most recently the then Environment, Transport and Works Bureau.

Subsequent to the re-organisation of government bureaux on 1 July 2007, a new Environment Bureau was formed to oversee the formulation and implementation of environmental policies.

On 8 March 2012, the department started reporting data on fine suspended particulates in the air on an hourly basis, that are a leading component of smog.

It began regular monitoring of PM2.5 levels, which measure 2.5 micrometres in diameter or less, at three stations since 2005, but the data were never publicised.