Is the air quality good in Hong Kong?
As of April 18, 2026, at 7 PM (local time GMT+8), Hong Kong is experiencing poor air quality. The AQI is 126, placing it 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 ranked as the 10th most polluted major city in the world on Saturday 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 2025 for Hong Kong was 15.7 µg/m³, corresponding to an AQI of 58 (“moderate”) and was 3.1 times the WHO annual guideline of 5 µg/m³.
Hong Kong ranked as the 10th most polluted major city on April 18, 2026. Source: IQAir.
When will air quality improve in Hong Kong?
Air quality in Hong Kong is expected to improve by tomorrow, transitioning into a moderate range.
Hourly air quality forecast for Hong Kong on April 18, 2026. Source: IQAir.
This suggests a reduction in pollutant concentrations, likely due to improving in meteorological conditions such as improved dispersion or shifts in wind patterns.
Air quality map of Hong Kong on April 18, 2026. Source: IQAir.
What is causing poor air quality in Hong Kong?
Poor air quality in Hong Kong is primarily driven by a combination of regional pollutant transport and local emissions. Elevated PM2.5 levels are associated with both primary emissions and secondary formation processes (1).
Key contributing factors include:
- Industrial emissions and coal combustion from regional sources transported by air masses
- Traffic-related pollution, including elemental carbon and trace metals with high toxicity (2)
- Atmospheric conditions such as stagnant air or subsidence that limit pollutant dispersion
- Seasonal and meteorological influences, including wind patterns and tropical cyclone positioning (3)
These factors lead to the accumulation of fine particulate matter across the city, resulting in widespread haze and degraded air quality.
How can I protect myself from poor air quality?
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Contribute to your community’s outdoor air quality data.
- Stay indoors when air quality is poor; if you do need to go outdoors, wear a KN95/FFP2 mask.
- Run a high-performance air purifier to filter particles, gases, and other pollutants.
