Hong Kong's air quality has continued to improve over the past 20 years, resulting in over a 50 percent reduction in long-term health risks, thanks to the efforts of the special administrative region government, the Environmental Protection Department said on Friday.

Announcing an overview of the city’s air quality in 2024, the EPD said the city’s air remained good overall and was broadly in compliance with the government’s air quality objectives.

From 2004 to 2024, the annual average concentrations of respirable suspended particulates, fine suspended particulates, nitrogen dioxide and sulphur dioxide in the ambient air have fallen by 45 percent to 88 percent. The annual average concentrations of these pollutants at the roadside have fallen by 36 percent to 88 percent, it said in a statement.

The annual average concentration of ozone has also steadied over the past few years. The number of hours of reduced visibility has declined by 82 percent since 2004.

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In recent years, the SAR government promoted electric vehicles, green transport and net-zero electricity generation in an effort to improve air quality in Hong Kong.

The department said that in 2024 the percentages of hourly Air Quality Health Index (AQHI) readings recorded by general and roadside monitoring stations that fell within “low” or “moderate” health risk parameters were 98.7 percent and 98.9 percent respectively. The comparable figures for 2014, the year the index launched, were 96.1 percent and 92.1 percent.

The department said it will update the risk factors assigned to air pollutants with reference to data derived from hospital admissions associated with air pollutants over the past decade.

It will also update its AQHI compilation methods with reference to the latest guideline levels for air pollutants published by the World Health Organization.

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“With the government's continued promotion and implementation of the comprehensive air quality improvement measures put forth in the Hong Kong Roadmap on Popularisation of Electric Vehicles, the Clean Air Plan for Hong Kong 2035 and Hong Kong's Climate Action Plan 2050 announced in 2021, and the Green Transformation Roadmap of Public Buses and Taxis announced in 2024, including the promotion of electric vehicles, green transport and net-zero electricity generation, the overall air quality in Hong Kong will improve continuously,” said an EPD spokesman.