EPD - 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).

Annual AQI Values

Air Pollutant Concentrations

Air Pollutant Concentrations (μg/m³)
Period: April 2021 - March 2022

General stations

Central/Western	Southern	Eastern	Kwun Tong
Sham Shui Po	Kwai Chung	Tsuen Wan	Tseung Kwan O
Yuen Long	Tuen Mun	Tung Chung	Tai Po
Sha Tin	North	Tap Mun

Roadside stations

Causeway Bay

Central

Mong Kok

Air Pollutant Concentrations (μg/m³)
Period: April 2021 - March 2022

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	32	23	15
Southern	29	24	12
Eastern	34	26	14
Kwun Tong	47	27	16
Sham Shui Po	45	25	13
Kwai Chung	48	24	16
Tsuen Wan	42	23	15
Tseung Kwan O	24	22	13
Yuen Long	39	27	17
Tuen Mun	41	32	18
Tung Chung	26	24	16
Tai Po	29	23	14
Sha Tin	29	22	13
North	34	23	14
Tap Mun	9	21	12

Pollutant concentrations in micrograms per cubic metre (μg/m³)

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	68	36	22
Central	65	27	17
Mong Kok	66	27	17

Pollutant concentrations in micrograms per cubic metre (μg/m³)

Annual AQI Values
Period: April 2021 - March 2022

General stations

Central/Western	Southern	Eastern	Kwun Tong
Sham Shui Po	Kwai Chung	Tsuen Wan	Tseung Kwan O
Yuen Long	Tuen Mun	Tung Chung	Tai Po
Sha Tin	North	Tap Mun

Roadside stations

Causeway Bay

Central

Mong Kok

Annual AQI Values
Period: April 2021 - March 2022

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.80	1.15	1.50
Southern	0.73	1.20	1.20
Eastern	0.85	1.30	1.40
Kwun Tong	1.18	1.35	1.60
Sham Shui Po	1.13	1.25	1.30
Kwai Chung	1.20	1.20	1.60
Tsuen Wan	1.05	1.15	1.50
Tseung Kwan O	0.60	1.10	1.30
Yuen Long	0.98	1.35	1.70
Tuen Mun	1.03	1.60	1.80
Tung Chung	0.65	1.20	1.60
Tai Po	0.73	1.15	1.40
Sha Tin	0.73	1.10	1.30
North	0.85	1.15	1.40
Tap Mun	0.23	1.05	1.20

AAQI = 12-month rolling concentrations/Annual WHO AQG concentration

Roadside

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	1.70	1.80	2.20
Central	1.63	1.35	1.70
Mong Kok	1.65	1.35	1.70

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):