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: October 2020 - September 2021

General Stations

StationNO2PM10PM2.5
Central/Western332716
Southern302713
Eastern353116
Kwun Tong473518
Sham Shui Po473014
Kwai Chung522616
Tsuen Wan432617
Tseung Kwan O252513
Yuen Long373217
Tuen Mun443820
Tung Chung262716
Tai Po322817
Sha Tin312714
North352616
Tap Mun102615
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay724124
Central693219
Mong Kok703119
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: October 2020 - September 2021

General Station

StationNO2PM10PM2.5
Central/Western0.831.351.60
Southern0.751.351.30
Eastern0.881.551.60
Kwun Tong1.181.751.80
Sham Shui Po1.181.501.40
Kwai Chung1.301.301.60
Tsuen Wan1.081.301.70
Tseung Kwan O0.631.251.30
Yuen Long0.931.601.70
Tuen Mun1.101.902.00
Tung Chung0.651.351.60
Tai Po0.801.401.70
Sha Tin0.781.351.40
North0.881.301.60
Tap Mun0.251.301.50
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.802.052.40
Central1.731.601.90
Mong Kok1.751.551.90
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

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Last revision date: 09:07 19-01-2022