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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: February 2020 - January 2021

General Stations

StationNO2PM10PM2.5
Central/Western332616
SouthernNANANA
Eastern342815
Kwun Tong453316
Sham Shui Po462914
Kwai Chung492414
Tsuen Wan372516
Tseung Kwan O242413
Yuen Long333216
Tuen Mun423621
Tung Chung292715
Tai Po322616
Sha Tin292615
NorthNANANA
Tap Mun92614
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay693823
Central693018
Mong Kok753019
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: February 2020 - January 2021

General Station

StationNO2PM10PM2.5
Central/Western0.831.301.60
SouthernNANANA
Eastern0.851.401.50
Kwun Tong1.131.651.60
Sham Shui Po1.151.451.40
Kwai Chung1.231.201.40
Tsuen Wan0.931.251.60
Tseung Kwan O0.601.201.30
Yuen Long0.831.601.60
Tuen Mun1.051.802.10
Tung Chung0.731.351.50
Tai Po0.801.301.60
Sha Tin0.731.301.50
NorthNANANA
Tap Mun0.231.301.40
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.731.902.30
Central1.731.501.80
Mong Kok1.881.501.90
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