New Air Quality Objectives Come into Effect–what are they and why are they important?

The amendments to the Air Pollution Control Ordinance, Cap. 311 come into effect today. Five of the statutory air quality objectives (‘AQOs’) have been tightened and three new objectives have been introduced referencing the Air Quality Guidelines (‘AQGs’) of the World Health Organization (‘WHO’). Please see the graphics below for details.

These AQOs are a set of standards for the concentration levels of seven major air pollutants and the number of exceedances permitted per year. The AQOs are formulated by the Environment and Ecology Bureau, subject to negative vetting by the Legislative Council, and are benchmarked against the WHO AQGs. The Air Pollution Control Ordinance requires the Administration to seek to achieve the AQOs as soon as is reasonably practicable. (Note 1)

CAN has been promoting improvement in air quality in Hong Kong so that the most stringent standards of the WHO AQGs will be attained since our establishment in 2009. We are pleased to see the Government’s pledge to achieve this in the long run at the launch of the Clean Air Plan 2035 in 2021 (note 2). We ask that the Government put forward the relevant timetable and roadmap as soon as possible, and in particular propose more stringent statutory AQOs.

The public consultation on the next review of Hong Kong’s AQOs is expected to take place in 2028. By then, the Government will have assessed the levels of major pollutants in Hong Kong in 2035 and whether we will meet the objective of ‘leading Hong Kong to become a more liveable city with air quality on par with major international cities by 2035’ in the Clean Air Plan 2035. We ask that the Government elaborate which major international cities they are studying for comparison and the air pollutant levels in these cities at present and expected in 2035, so the public will understand the relative situation in Hong Kong.

Lastly, there are no statutory objectives for indoor air in Hong Kong. We call for the introduction of such objectives with regular reviews, like those for ambient air, in our legislation.

Read our full statement on the amendments to the ordinance here.

Notes

[1] The WHO AQGs set out four interim targets and an ultimate objective for each pollutant, with interim target 1 being the loosest standard. According to the Hong Kong Government’s air quality assessment, in 2030, for these three of the seven major air pollutants, Hong Kong will meet the WHO ultimate objective: sulphur dioxide, carbon monoxide and lead. The remaining four are respirable suspended particulates (PM10) (meeting interim target 3), fine suspended particulates (PM2.5) (meeting interim target 3), nitrogen dioxide (meeting interim target 1) and ozone (meeting interim target 1).

[2] Then Secretary for the Environment, Wong Kam-sing, said at the launch of the Clean Air Plan 2035, ‘The Clean Air Plan for Hong Kong 2035 we are releasing today will carry on the past successes to the future, leading Hong Kong to be a more liveable city with air quality on par with major international cities by 2035, and advancing towards the target of meeting in full the ultimate standards of the World Health Organization Air Quality Guidelines in the long run.’

11 April 2025