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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: April 2018 - March 2019

General Stations

StationNO2PM10PM2.5
Central/Western393220
Eastern383118
Kwun Tong433621
Sham Shui Po483220
Kwai Chung543119
Tsuen Wan452919
Tseung Kwan O282815
Yuen Long443519
Tuen Mun464024
Tung Chung343118
Tai Po353019
Sha Tin333118
Tap Mun113017
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay824428
Central783421
Mong Kok773423
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: April 2018 - March 2019

General Station

StationNO2PM10PM2.5
Central/Western0.981.602.00
Eastern0.951.551.80
Kwun Tong1.081.802.10
Sham Shui Po1.201.602.00
Kwai Chung1.351.551.90
Tsuen Wan1.131.451.90
Tseung Kwan O0.701.401.50
Yuen Long1.101.751.90
Tuen Mun1.152.002.40
Tung Chung0.851.551.80
Tai Po0.881.501.90
Sha Tin0.831.551.80
Tap Mun0.281.501.70
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay2.052.202.80
Central1.951.702.10
Mong Kok1.931.702.30
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Remarks:

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

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

(3) 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.

(4) 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.