IQAir Staff Writers

Is the air quality good in Hong Kong?

On October 27, 2025, at 2:20 AM PT, Hong Kong is experiencing poor air quality. The AQI is 106 and falls in the “unhealthy for sensitive groups” range, with PM2.5 concentrations dominating.

Air quality is dynamic and, like the weather, can change frequently. Hong Kong ranks as the 10th most polluted major city in the world on Monday morning.

Click here for a real-time air quality map of Hong Kong.

While the air quality conditions today are unusually poor, it is important to keep in mind that the average PM2.5 concentration in 2024 for Hong Kong was 16.4 µg/m³, corresponding to an AQI of 59 (“moderate”) and was 3 times the WHO annual guideline of 5 µg/m³.


Hong Kong ranked as the 10th most polluted major city on Oct 27, 2025. Source: IQAir.

When will air quality improve in Hong Kong?

Improvements depend primarily on changes in wind direction and ventilation.

Forecasts indicate that the hazy episode will ease once the northerly, dust carrying air stream weakens and meteorological conditions become more ventilated (1).

Short term outlooks are highly weather dependent so expect fluctuations through the day.


Hourly air quality forecast for Hong Kong on Oct 27, 2025. Source: IQAir.

What is causing poor air quality in Hong Kong?

Multiple factors contribute to the current poor air quality. Key causes include:

Local road traffic emissions which increase roadside NOx and particulate exposure especially during business hours (2).
Regional transport of pollution and dust including northerly airstreams that carry desert sand and pollutants from mainland sources (3).
Particle composition that increases toxicity such as trace metals and insoluble elemental carbon which elevate acute reactive oxygen species and chronic risk.
Combined urban background and episodic meteorology that reduces dispersion and concentrates pollutants at ground level (4).


Air quality map of Hong Kong on Oct 27, 2025. Source: IQAir.

How can I protect myself from poor air quality?