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: September 2021 - August 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: September 2021 - August 2022

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	31	22	14
Southern	26	23	12
Eastern	33	25	13
Kwun Tong	47	26	15
Sham Shui Po	44	24	13
Kwai Chung	46	23	15
Tsuen Wan	41	22	14
Tseung Kwan O	22	22	12
Yuen Long	39	26	17
Tuen Mun	41	32	18
Tung Chung	26	23	16
Tai Po	28	21	14
Sha Tin	28	21	13
North	33	23	13
Tap Mun	8	20	12

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

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	64	34	21
Central	62	27	17
Mong Kok	63	26	16

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

Annual AQI Values
Period: September 2021 - August 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: September 2021 - August 2022

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.78	1.10	1.40
Southern	0.65	1.15	1.20
Eastern	0.83	1.25	1.30
Kwun Tong	1.18	1.30	1.50
Sham Shui Po	1.10	1.20	1.30
Kwai Chung	1.15	1.15	1.50
Tsuen Wan	1.03	1.10	1.40
Tseung Kwan O	0.55	1.10	1.20
Yuen Long	0.98	1.30	1.70
Tuen Mun	1.03	1.60	1.80
Tung Chung	0.65	1.15	1.60
Tai Po	0.70	1.05	1.40
Sha Tin	0.70	1.05	1.30
North	0.83	1.15	1.30
Tap Mun	0.20	1.00	1.20

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

Roadside

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	1.60	1.70	2.10
Central	1.55	1.35	1.70
Mong Kok	1.58	1.30	1.60

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):