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Latest Annual AQI

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: December 2019 - November 2020

General Stations

StationNO2PM10PM2.5
Central/Western322516
SouthernNANANA
Eastern342714
Kwun Tong433216
Sham Shui Po462814
Kwai Chung482314
Tsuen Wan372415
Tseung Kwan O232412
Yuen Long333116
Tuen Mun413320
Tung Chung282414
Tai Po302415
Sha Tin282415
NorthNANANA
Tap Mun92513
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay693622
Central692917
Mong Kok752918
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: December 2019 - November 2020

General Station

StationNO2PM10PM2.5
Central/Western0.801.251.60
SouthernNANANA
Eastern0.851.351.40
Kwun Tong1.081.601.60
Sham Shui Po1.151.401.40
Kwai Chung1.201.151.40
Tsuen Wan0.931.201.50
Tseung Kwan O0.581.201.20
Yuen Long0.831.551.60
Tuen Mun1.031.652.00
Tung Chung0.701.201.40
Tai Po0.751.201.50
Sha Tin0.701.201.50
NorthNANANA
Tap Mun0.231.251.30
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.731.802.20
Central1.731.451.70
Mong Kok1.881.451.80
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