Singapore legislation
Regulation 3
of Transboundary Haze Pollution (Air Quality) Regulations 2014
Regulation 3
Air quality index
The 24‑hour Pollutant Standards Index (PSI) adopted by the Agency for the average level of particulate matter in an area’s outdoor air environment that is less than or equal to 2.5 micrometres in aerodynamic diameter (PM2.5), at any time obtained over a 24 hour period immediately preceding that time, is the area’s air quality index for the purposes of the Act.