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: October 2019 - September 2020

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: October 2019 - September 2020

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	33	26	17
Southern	NA	NA	NA
Eastern	34	27	15
Kwun Tong	43	33	17
Sham Shui Po	47	28	15
Kwai Chung	50	25	15
Tsuen Wan	39	25	16
Tseung Kwan O	25	25	14
Yuen Long	36	33	17
Tuen Mun	42	35	21
Tung Chung	29	24	15
Tai Po	32	25	16
Sha Tin	29	25	15
North	NA	NA	NA
Tap Mun	9	26	14

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

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	71	37	23
Central	71	30	18
Mong Kok	76	30	19

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

Annual AQI Values
Period: October 2019 - September 2020

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: October 2019 - September 2020

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.83	1.30	1.70
Southern	NA	NA	NA
Eastern	0.85	1.35	1.50
Kwun Tong	1.08	1.65	1.70
Sham Shui Po	1.18	1.40	1.50
Kwai Chung	1.25	1.25	1.50
Tsuen Wan	0.98	1.25	1.60
Tseung Kwan O	0.63	1.25	1.40
Yuen Long	0.90	1.65	1.70
Tuen Mun	1.05	1.75	2.10
Tung Chung	0.73	1.20	1.50
Tai Po	0.80	1.25	1.60
Sha Tin	0.73	1.25	1.50
North	NA	NA	NA
Tap Mun	0.23	1.30	1.40

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

Roadside

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	1.78	1.85	2.30
Central	1.78	1.50	1.80
Mong Kok	1.90	1.50	1.90

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):