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: August 2022 - July 2023

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: August 2022 - July 2023

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	31	23	15
Southern	25	27	13
Eastern	32	25	15
Kwun Tong	43	26	15
Sham Shui Po	44	24	12
Kwai Chung	46	26	16
Tsuen Wan	39	24	16
Tseung Kwan O	22	25	16
Yuen Long	37	26	17
Tuen Mun	38	35	18
Tung Chung	25	24	15
Tai Po	27	25	16
Sha Tin	27	23	13
North	31	26	16
Tap Mun	8	23	13

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

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	69	38	23
Central	66	28	19
Mong Kok	70	29	18

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

Annual AQI Values
Period: August 2022 - July 2023

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: August 2022 - July 2023

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.78	1.15	1.50
Southern	0.63	1.35	1.30
Eastern	0.80	1.25	1.50
Kwun Tong	1.08	1.30	1.50
Sham Shui Po	1.10	1.20	1.20
Kwai Chung	1.15	1.30	1.60
Tsuen Wan	0.98	1.20	1.60
Tseung Kwan O	0.55	1.25	1.60
Yuen Long	0.93	1.30	1.70
Tuen Mun	0.95	1.75	1.80
Tung Chung	0.63	1.20	1.50
Tai Po	0.68	1.25	1.60
Sha Tin	0.68	1.15	1.30
North	0.78	1.30	1.60
Tap Mun	0.20	1.15	1.30

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

Roadside

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	1.73	1.90	2.30
Central	1.65	1.40	1.90
Mong Kok	1.75	1.45	1.80

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):