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 2020 - March 2021

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 2020 - March 2021

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	34	26	16
Southern	NA	NA	NA
Eastern	34	29	15
Kwun Tong	48	34	17
Sham Shui Po	47	29	14
Kwai Chung	51	25	15
Tsuen Wan	38	25	16
Tseung Kwan O	25	24	13
Yuen Long	34	32	16
Tuen Mun	43	37	21
Tung Chung	28	27	15
Tai Po	32	26	16
Sha Tin	31	27	15
North	NA	NA	NA
Tap Mun	10	26	14

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

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	71	39	23
Central	69	30	18
Mong Kok	73	30	19

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

Annual AQI Values
Period: April 2020 - March 2021

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 2020 - March 2021

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.85	1.30	1.60
Southern	NA	NA	NA
Eastern	0.85	1.45	1.50
Kwun Tong	1.20	1.70	1.70
Sham Shui Po	1.18	1.45	1.40
Kwai Chung	1.28	1.25	1.50
Tsuen Wan	0.95	1.25	1.60
Tseung Kwan O	0.63	1.20	1.30
Yuen Long	0.85	1.60	1.60
Tuen Mun	1.08	1.85	2.10
Tung Chung	0.70	1.35	1.50
Tai Po	0.80	1.30	1.60
Sha Tin	0.78	1.35	1.50
North	NA	NA	NA
Tap Mun	0.25	1.30	1.40

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

Roadside

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	1.78	1.95	2.30
Central	1.73	1.50	1.80
Mong Kok	1.83	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):