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Hong Kong air pollution

New air quality goals expected to bring in HK$33 billion in economic benefits for Hong Kong but green groups say objectives are too conservative

  • Proposed daily levels for key pollutants tightened, but number of times limits can be breached yearly rises drastically
  • Standards, once approved, will come into effect in 2020 for five years even though WHO guidelines slated to be revised soon
PUBLISHED : Tuesday, 18 December, 2018, 9:30am
UPDATED : Tuesday, 18 December, 2018, 11:37pm

More than two dozen short-term measures have been proposed to improve Hong Kong’s air as part of a new set of “air quality objectives”.

The health impact from the 27 measures are expected to bring in the city HK$33 billion in economic benefits, mostly from reduced hospital admissions and 1,850 premature deaths averted, according to the government’s proposed air quality objectives for 2025.

But proposals to tighten maximum levels of two key pollutants – fine suspended particulates and sulphur dioxide (SO2) – have been criticised as being “overly conservative”.

The objectives, which also include concentration limits for five other pollutants and the number of times levels can be exceeded, are benchmarked against World Health Organisation guidelines.

A compilation of results of a two-year review of the current air quality objectives were presented to a working group on Tuesday, but a coalition of 16 environmental groups, lawmakers, medical organisations, including the Doctors Union and the Thoracic Society, staged a protest – some in gas masks – outside government offices before the meeting.

The objectives were expected to come into effect around 2020 for five years although the WHO is slated to revise its own guidelines soon.

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Targets for fine suspended particulates (PM2.5) are proposed to be tightened from the current annual average of 35 micrograms per cubic metre of air, to 25mcg. The 24-hour average is to be tightened from 75mcg to 50mcg.

But the number of times those 24-hour average targets could be breached in a year was also raised drastically, from nine to 35.

Objectives for SO2 emissions were tightened from 125mcg over a 24-hour average to 50mcg. All figures comply with a second set of three interim WHO targets.

Of the 70 recommendations floated during the review, 27 were considered by sub-working groups to be feasible and could produce results by 2025 or earlier, such as reviewing tunnel toll policies, promoting more “pedestrian-friendly” environments and replacing more coal-fired power plants.

The estimated HK$33 billion in economic benefits is based on a “business as usual” scenario up to 2025 and does not take into account the tightening of targets.

No tweaks will be made to other pollutants such as ozone and respirable suspended particulates (PM10), as tightening them further would be unrealistic.

“The 2025 air quality assessment results show that the concentrations of PM10 and ozone in 2025 will not be able to meet the AQOs, if they are to be tightened to the next level,” the department’s paper said.

Ozone limits, at an average of 160mcg over an hour and higher than the WHO’s recommended 100, will also stay the same. Ozone levels hit a two-decade high this year and are widely seen as the most pressing air quality problem for the region.

“We believe the recommendations violate the review principle of ‘public health first’ and the Environmental Protection Department aimed to merely meet targets when making the recommendations,” according to the AQO Review Coalition.

Low awareness of bad air health risks in Hong Kong, green group says

“The [objectives] continue to significantly fall short of the safety standards established by the WHO. In other words, even if the city’s future air quality complies with the department’s recommended AQO, [Hongkongers’] health will continuously be affected by air pollution.”

Typically produced in the burning of fuel, PM2.5 are microscopic airborne particles small enough to lodge deep in the lungs and cause damage. Ships and power plants are the biggest sources of SO2.

“They already know that once they implement all the short-term policy measures, the second interim target [for PM2.5] will be met easily,” said Loong Tsz-wai of the Clean Air Network, who sits on one of the review groups.

“At certain times, PM2.5 is already hovering at around 24mcg so I think this target is more than conservative. They are playing a numbers game.”

He also questioned why the SO2 targets were so unambitious given that levels had already been declining significantly since legislation came into effect in 2015 requiring ships to switch to cleaner fuel at berth.

Between 1997 and 2016, SO2 emissions dropped by 78 per cent, thanks to stricter emissions standards for power plants.

No tweaks will be made to other pesky pollutants such as ozone and respirable suspended particulates (PM10), as tightening them further would be unrealistic, according to sources.

Ozone limits, at an average of 160mcg over an hour and higher than the WHO’s recommended 100mcg, will also stay the same. Ozone levels hit a two-decade high this year and are widely seen as the most pressing air quality problem for the region.

Hong Kong ‘needs to rethink’ how it approaches clean air issue

The last time Hong Kong’s air quality objectives were updated was in 2014, mandating for the first time a periodic review every five years. Before that, the objectives had not been adjusted since coming into effect in 1987.

The WHO guidelines, established in 2005, are seen worldwide as the appropriate targets for safe air, but it also publishes a three-tier scale of interim targets that governments can strive to climb progressively, according to “local circumstances”.

The international agency started the work on preparing an update of the guidelines in 2016.