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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 2022 - January 2023

General Stations

StationNO2PM10PM2.5
Central/Western292214
Southern252512
Eastern322313
Kwun Tong442414
Sham Shui Po422412
Kwai Chung432315
Tsuen Wan392314
Tseung Kwan O212314
Yuen Long362516
Tuen Mun383218
Tung Chung242213
Tai Po272114
Sha Tin262113
North302314
Tap Mun72012
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Roadside Stations

StationNO2 PM10PM2.5
Causeway Bay653420
Central622617
Mong Kok632616
Pollutant concentrations in micrograms per cubic metre (μg/m3)

Annual AQI Values
Period: February 2022 - January 2023

General Station

StationNO2PM10PM2.5
Central/Western0.731.101.40
Southern0.631.251.20
Eastern0.801.151.30
Kwun Tong1.101.201.40
Sham Shui Po1.051.201.20
Kwai Chung1.081.151.50
Tsuen Wan0.981.151.40
Tseung Kwan O0.531.151.40
Yuen Long0.901.251.60
Tuen Mun0.951.601.80
Tung Chung0.601.101.30
Tai Po0.681.051.40
Sha Tin0.651.051.30
North0.751.151.40
Tap Mun0.181.001.20
AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

StationNO2PM10PM2.5
Causeway Bay1.631.702.00
Central1.551.301.70
Mong Kok1.581.301.60
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