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  • Dec 21, 2014
  • Updated: 10:32am
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Hong Kong's new air quality health index shows changes at four out of nine monitoring stations

But more moderate gradings of pollutants does not mean new system is less stringent

PUBLISHED : Tuesday, 24 December, 2013, 5:15am
UPDATED : Friday, 27 December, 2013, 9:28am

Air quality recordings released yesterday after a trial run of the government's new index at its nine monitoring stations showed that three "highs" under the old system had become "moderate" under the new one.

One recording turned from "high" to "very high". Recordings at the other five stations were "very high" or "high" under both indices. But environmentalists said this did not mean that the new index, the air quality health index (AQHI), was less stringent than the old one - the air pollution index (API).

"In fact, it reflects the health risk the pollution brings to the public more accurately," said Melonie Chau Yuet-cheung, senior environmental affairs officer with Friends of the Earth.

Introduced in 1995, the API converts air pollution data into a value ranging from 0 to 500, putting it under five bands from "low" to "severe".

Experts say the AQHI, which will be officially launched on Monday, will offer the public better, clearer and more timely advice on health risks than the present system.

It calculates the hospital admission risks brought about by air pollutants. There are 10 bands under this new index. They consist of five categories from "low" to "serious".

The old index reflects the intensity of air pollution, which means the recordings refer to the "air pollution level". However, the new index indicates the health risk arising from pollution, and the recordings therefore reflect the "health risk level".

Results from the trial run showed that the 5pm readings for Eastern district, Kwun Tong and Tai Po were "high" under the API, suggesting that there was no need for the public to take immediate action. The readings for the three became "moderate" under the AQHI, again meaning that no immediate action was needed.

Meanwhile, the reading for Yuen Long turned from "high" to "very high" under the AQHI. In this case the new index advises the public to reduce outdoor activities, while the old one does not.

Chau welcomed the new index as it can better reflect the health risk of air pollution.

"API calculates the intensity of five air pollutants. It means that if only one of the five pollutants is exceptionally high, the reading will come out high," Chau said. "But the thing is, in order for the pollution to be harmful to your health, we need to consider the combination of the five pollutants. The new index was structured in a way to achieve this."

But Chau said one problem with the new index was that it still did not stipulate that government departments must take certain measures such as banning cars from the streets when pollution was severe.

This was a measure that Beijing had already taken and Hong Kong should consider, she added.

Roy Tam Hoi-pong, chairman of Green Sense, also welcomed the new index as it measures PM2.5 - tiny particles that are particularly hazardous to health - which were not calculated under the old API.

After the public had taken some time to get used to the new index, he said, the government should consider making it mandatory to suspend school classes if pollution hits the worst level.

Watch: How to deal with Hong Kong's smog


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This article is now closed to comments

'But Chau said one problem with the new index was that it still did not stipulate that government departments must take certain measures such as banning cars from the streets when pollution was severe'
Our major polluter is ocean going vessels burning bunker sludge with 2.75 - 4% sulphur content & the wind direction
We have no shipping emissions control area as a legacy of Edward Yau + Bowtie whereas USA/Canada have a 200 nautical mile ECA in which OGVs must switch to low sulphur fuel
The Baltic + North sea also have ECAs. HKG port handled 23 million TEUs last year, Shenzhen port at Deep Bay 24 million TEUs & Yantian port in Mirs Bay over 10m TEUs
Yesterday the winds over Deep Bay were shown on HKO as SSW & surprise, Yuen Long had a dangerous AQHI of 8 on the new scale with all the pollutant shxt from Deep Bay blown straight at YL.
Easterly winds over Mirs bay with ships enroute Yantian port explain why Tap Mun is always shrouded in NOx/ SOx & particulates
New AQH index
Hong Kong Air Pollution: Real-time PM2.5 Air Quality Index
This is just a taste of what will happen if Legco lets the blinkered Govt build a toxic incinerator spewing dioxin/furans + cadmium RSPs all over the city
The index is meaningless and a distraction without it being tied to real action against the sources of air pollution. Despite its claimed determination to tackle the filth in the air, we can all see the government is doing little that has a tangible impact. Clearly the polluters are to be allowed to continue unhindered. As a side issue, and in a master stroke, CY has silenced an eloquent critic by having Christine LOH appointed to a government position. Anyway, Hong Kong is doomed to go the way of all the cities on the mainland, because profit comes before peoples health.
Dai Muff
What I want is to see the API given out alongside the weather and on the Observatory website as many other countries do. Not hidden away somewhere else so it takes extra steps to find it.
it is at least a step forward that the current Govt recognises the impact of pollution on health unlike the past Yau moron who did SFA during his tenure except taking 60 overseas jollies during 60 months in the overpaid job
Lot of reporting (which is hard to find) as Stagger Lee says. But, sadly, overall there is a lot of talk and little accountable action. Lot of pollution from ships - who is looking into that? Perhaps the power structure of HK eliminates any chances of effective action. Give us reasons to have hope - please....
Moderate is better than high, but low would be better than moderate! And why are several districts not even being monitored using the new index? Waiting for conversion or out of plan?
What’s the point of recalibrating the air quality index just so that it reports a more favorable figure? Doesn’t that just defeat the purpose of having air quality monitors?
The best our govt can do to address any of the problems we face is to "monitor the situation closely" and this new format fits the bill nicely.
Read 'n learn
'16 super-ships can emit as much sulfur as the world's fleet of cars’
‘For decades, the IMO has rebuffed calls to clean up ship pollution. As a result, while it has long since been illegal to belch black, sulfur-laden smoke from power-station chimneys or lorry exhausts, shipping has kept its licence to pollute. For 31 years, the IMO has operated a policy agreed by the 169 governments that make up the organisation which allows most ships to burn bunker fuel. Christian Moller, boss of the DK shipping company in Rotterdam, recently described this as ‘just waste oil, basically what is left over after all the cleaner fuels have been extracted from crude oil. It’s tar, the same as asphalt. It’s the cheapest & dirtiest fuel in the world’. Bunker fuel is also thick with sulfur. IMO rules allow ships to burn fuel containing up to 4.5 per cent sulfur. That is 4,500 times more than is allowed in car fuel in the EU. The sulfur comes out of ship funnels as tiny particles,& it is these that get deep into lungs. Thanks to the IMO’s rules, the largest ships can each emit as much as 5,000 tons of sulphur in a year – the same as 50million typical cars, each emitting an average of 100 grams of sulphur a year. With an estimated 800million cars driving around the planet, that means 16 super-ships can emit as much sulfur as the world fleet of cars’
Sad, but true. There is no consideration for ship pollution. Clearly the container ports are considered a sacred cow -- xx yrs of life expectancy is such a long term thing that its easy to sacrifice. But hey we project the interests of business.



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