The Air Pollution Index was replaced by the Air Quality Health Index on December 30, 2013. This page will not be updated until further notice.
Air Pollution Levels
The following shows the air pollution levels across Hong Kong, subdivided according to the types of pollutants and duration laid down here. Please click here for the calculations involved. Note that the values in the "index" column may not equal the true index shown in official pages due to rounding errors. Graphs for the concentrations of pollutants are shown on the right.
Data as of HKT
Sub indices
Index
Station
RSP (24-hr)
SO2 (24-hr)
SO2 (1-hr)
NO2 (24-hr)
NO2 (1-hr)
CO (8-hr)
CO (1-hr)
O3 (1-hr)
General Station
N/A
Central/Western
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Eastern
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Kwai Chung
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Kwun Tong
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Sha Tin
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Sham Shui Po
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tai Po
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tap Mun
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tsuen Wan
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tung Chung
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Yuen Long
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Roadside Station
N/A
Causeway Bay
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Central
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Mong Kok
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Pollutant concentration (microgram / cubic metre)
Station
RSP (24-hr)
SO2 (24-hr)
SO2 (1-hr)
NO2 (24-hr)
NO2 (1-hr)
CO (8-hr)
CO (1-hr)
O3 (1-hr)
General Station
Central/Western
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Eastern
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Kwai Chung
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Kwun Tong
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Sha Tin
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Sham Shui Po
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tai Po
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tap Mun
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tsuen Wan
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Tung Chung
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Yuen Long
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Roadside Station
Causeway Bay
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Central
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Mong Kok
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Notes:
Pollution levels are represented by the following colours:
Green : Low (Index between 0 and 25)
Blue : Medium (Index between 26 and 50)
Yellow : High (Index between 51 and 100)
Red : Very High (Index between 101 and 200)
Black : Severe (Index between 201 and 500)
The graphs on the right are shaded according to the colour scheme in (1) above, subject to the duration selected which is explained in (3) below.
The "Duration" option switches the time period depending on which the pollution levels for various pollutants are determined. According to this page, a number of pollutants have two sub-indices, and for the sub-index representing the shorter duration (e.g. the concentration in the past hour is "short", while the average concentration over 24 hours is "long") to achieve the same pollution level, a higher concentration is usually necessary. For pollutants that have only one classification according to duration, the charts generated are the same no matter which "Duration" option is chosen. The duration for each pollutant under each option is tabulated below:
The circle near the right hand side of each plot represents the average pollutant concentration over the "long" duration specified in the above table. As such, they will only be visible in the "long" duration plots.
Last Accessed: Sat Mar 22 2025 14:41:08 HKT
Last Modified: Mon Dec 30 2013
Air Pollution Levels