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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: May 2019 - April 2020

General Stations

StationNO2PM10PM2.5
Central/Western352919
Eastern363117
Kwun Tong433719
Sham Shui Po473217
Kwai Chung512717
Tsuen Wan422818
Tseung Kwan O272916
Yuen Long413619
Tuen Mun463923
Tung Chung312717
Tai Po342919
Sha Tin312716
Tap Mun93117
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay784126
Central783522
Mong Kok803422
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: May 2019 - April 2020

General Station

StationNO2PM10PM2.5
Central/Western0.881.451.90
Eastern0.901.551.70
Kwun Tong1.081.851.90
Sham Shui Po1.181.601.70
Kwai Chung1.281.351.70
Tsuen Wan1.051.401.80
Tseung Kwan O0.681.451.60
Yuen Long1.031.801.90
Tuen Mun1.151.952.30
Tung Chung0.781.351.70
Tai Po0.851.451.90
Sha Tin0.781.351.60
Tap Mun0.231.551.70
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.952.052.60
Central1.951.752.20
Mong Kok2.001.702.20
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