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: July 2020 - June 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: July 2020 - June 2021

General Stations

Station	NO₂	PM₁₀	PM_2.5
Central/Western	33	27	16
Southern	29	27	14
Eastern	35	30	15
Kwun Tong	46	35	17
Sham Shui Po	46	30	14
Kwai Chung	51	26	15
Tsuen Wan	40	26	16
Tseung Kwan O	24	24	13
Yuen Long	34	32	16
Tuen Mun	42	38	20
Tung Chung	26	27	16
Tai Po	32	27	16
Sha Tin	30	27	15
North	34	26	15
Tap Mun	9	26	15

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

Roadside Stations

Station	NO₂	PM₁₀	PM_2.5
Causeway Bay	71	40	24
Central	69	31	18
Mong Kok	70	31	19

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

Annual AQI Values
Period: July 2020 - June 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: July 2020 - June 2021

General Station

Station	NO₂	PM₁₀	PM_2.5
Central/Western	0.83	1.35	1.60
Southern	0.73	1.35	1.40
Eastern	0.88	1.50	1.50
Kwun Tong	1.15	1.75	1.70
Sham Shui Po	1.15	1.50	1.40
Kwai Chung	1.28	1.30	1.50
Tsuen Wan	1.00	1.30	1.60
Tseung Kwan O	0.60	1.20	1.30
Yuen Long	0.85	1.60	1.60
Tuen Mun	1.05	1.90	2.00
Tung Chung	0.65	1.35	1.60
Tai Po	0.80	1.35	1.60
Sha Tin	0.75	1.35	1.50
North	0.85	1.30	1.50
Tap Mun	0.23	1.30	1.50

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	1.73	1.55	1.80
Mong Kok	1.75	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):