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: November 2020 - October 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: November 2020 - October 2021

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	33	26	16
Southern	30	26	13
Eastern	35	30	15
Kwun Tong	47	33	17
Sham Shui Po	47	29	14
Kwai Chung	51	26	16
Tsuen Wan	43	25	16
Tseung Kwan O	25	24	13
Yuen Long	37	31	16
Tuen Mun	43	37	20
Tung Chung	26	26	16
Tai Po	32	27	16
Sha Tin	30	26	14
North	35	26	15
Tap Mun	10	25	14

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

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	71	40	24
Central	68	31	19
Mong Kok	69	31	19

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

Annual AQI Values
Period: November 2020 - October 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: November 2020 - October 2021

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.83	1.30	1.60
Southern	0.75	1.30	1.30
Eastern	0.88	1.50	1.50
Kwun Tong	1.18	1.65	1.70
Sham Shui Po	1.18	1.45	1.40
Kwai Chung	1.28	1.30	1.60
Tsuen Wan	1.08	1.25	1.60
Tseung Kwan O	0.63	1.20	1.30
Yuen Long	0.93	1.55	1.60
Tuen Mun	1.08	1.85	2.00
Tung Chung	0.65	1.30	1.60
Tai Po	0.80	1.35	1.60
Sha Tin	0.75	1.30	1.40
North	0.88	1.30	1.50
Tap Mun	0.25	1.25	1.40

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

Roadside

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	1.78	2.00	2.40
Central	1.70	1.55	1.90
Mong Kok	1.73	1.55	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):