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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: September 2018 - August 2019

General Stations

StationNO2PM10PM2.5
Central/Western393020
Eastern383017
Kwun Tong443520
Sham Shui Po473019
Kwai Chung532818
Tsuen Wan452819
Tseung Kwan O282715
Yuen Long433419
Tuen Mun463924
Tung Chung333119
Tai Po352919
Sha Tin322917
Tap Mun112916
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay794227
Central783522
Mong Kok783323
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: September 2018 - August 2019

General Station

StationNO2PM10PM2.5
Central/Western0.981.502.00
Eastern0.951.501.70
Kwun Tong1.101.752.00
Sham Shui Po1.181.501.90
Kwai Chung1.331.401.80
Tsuen Wan1.131.401.90
Tseung Kwan O0.701.351.50
Yuen Long1.081.701.90
Tuen Mun1.151.952.40
Tung Chung0.831.551.90
Tai Po0.881.451.90
Sha Tin0.801.451.70
Tap Mun0.281.451.60
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.982.102.70
Central1.951.752.20
Mong Kok1.951.652.30
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.