Welcome to Environmental Protection Department Air Quality Health Index Website


The Annual Air Quality Index (AAQI) is the ratio of the past 12-month rolling average concentration to the annual air quality guidelines (AQG) of the World Health Organization (WHO).

Air Pollutant Concentrations (μg/m3)
Period: January 2023 - December 2023

General Stations

StationNO2PM10PM2.5
Central/Western322214
Southern262512
Eastern322414
Kwun Tong412615
Sham Shui Po432413
Kwai Chung502516
Tsuen Wan402415
Tseung Kwan O222415
Yuen Long372616
Tuen Mun403419
Tung Chung262214
Tai Po272515
Sha Tin272213
North302715
Tap Mun82212
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay673923
Central632919
Mong Kok682918
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: January 2023 - December 2023

General Station

StationNO2PM10PM2.5
Central/Western0.801.101.40
Southern0.651.251.20
Eastern0.801.201.40
Kwun Tong1.031.301.50
Sham Shui Po1.081.201.30
Kwai Chung1.251.251.60
Tsuen Wan1.001.201.50
Tseung Kwan O0.551.201.50
Yuen Long0.931.301.60
Tuen Mun1.001.701.90
Tung Chung0.651.101.40
Tai Po0.681.251.50
Sha Tin0.681.101.30
North0.751.351.50
Tap Mun0.201.101.20
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.681.952.30
Central1.581.451.90
Mong Kok1.701.451.80
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Remarks:

(1) The AAQI is updated monthly. The AAQI is calculated based on validated monitoring data.

(2) An AAQI greater than one indicates that the health risk resulted from long-term exposure is higher than that of the WHO's annual AQG, whereas an index below one means a lower risk.

(3) WHO’s annual AQG (2006):


Annual WHO AQG
(μg/m3)
NO2 40
PM10 20
PM2.5 10

Reference: http://www.who.int/phe/health_topics/outdoorair/outdoorair_aqg/en/index.html

For further information about the annual AQI, please visit the FAQ.

(4) NO2 - nitrogen dioxide, PM10 - respirable suspended particulates, PM2.5 - fine suspended particulates

Last revision date: 00:07 27-04-2024