As social and economic activity resumed in full in 2023, emissions of air pollutants in Hong Kong returned to normal levels, while ambient air pollutants increased slightly compared to 2022. 

The Environmental Protection Department unveiled these findings today as it gave an overview of Hong Kong's air quality in 2023.

The department noted that notwithstanding a hike of 1 to 2μg per cubic metre in levels of respirable suspended particulates, fine suspended particulates, nitrogen dioxide and sulphur dioxide, air quality last year was the second best since Hong Kong’s return to the motherland.

Except for fine suspended particulates, which remained at a similar level, the ambient levels of the other air pollutants improved by between 7 and 20% compared to 2021 levels, indicating an overall improvement trend.

Since 2011, annual average concentrations of the four abovementioned components in the ambient air have fallen by between 40 and 69%, while annual average roadside pollutant concentrations have decreased by between 46 and 58%.

The annual average concentration of ozone has also gradually steadied in the past few years, with the number of hours of reduced visibility falling 81% from a peak in 2004.

On regional collaboration, the department said a three-year study titled “Characterization of photochemical ozone formation, regional and super-regional transportation in the Greater Bay Area” has been completed, and will improve understanding of the causes of ozone formation within the region.

The governments of Guangdong, Hong Kong and Macau will also work together in four directions to further improve air quality in the Pearl River Delta Region. These are reducing nitrogen oxides and volatile organic compound emissions, controlling ozone and fine suspended particulates, controlling air pollutants and greenhouse gases, and managing overall regional air quality.