Smog

We have had a number of hazy and high-pollution days recently, and accordingly a lot of comment in the local papers (e.g. SCMP here, here and here).

I found some research from HK university confirming the common impression that many pollutants are worse in winter (Nov-Feb) because the prevailing wind is blowing from the north and the factories of the Pearl River Delta   "NO2, RSP, CO and SO2 - higher (Hong Kong mostly in downwind position of pollution sources of mainland)"  (hku thesis).

Tues 27-Jan 3pm  IFC and Hong Kong Island 

This paper says the pollution is a serious health risk:   "Hedley et al. (2006) suggested that 1.13% increase in all natural causes of death is resulted from each 6.5 km reduction in visibility, where the loss in visibility reflects the degradation in our air quality.   The study also suggested 36,000 to 64,000 hospital bed-days admissions can be avoided annually by improving our air quality from annual average level. In terms of costs, $1 billion to $1.5 billion of health care costs, $0.3 to 0.5 billion of productivity loss and $19 billion of intangible costs can be avoided".

Tues 27-Jan 3pm Stonecutters Island

So we regularly check the air quality using the AQICN website, (which also covers China, Japan and Europe).  The index for Hong Kong is often at unhelthy levels, and usually much higher than say, Tokyo or London.

For example, at the time I took the photos above, this site rated the air quality in Hong Kong as 'unhealthy', mainly due to RSPs  respirable suspended particle  measured by PM 2.5 (fine particles diameter of 2.5 micrometres or less) and PM10 (particles with diameter of 10 micrometres or less).

AQICN Tues 27-Jan 3pm

The index for Shatin, the closest monitoring station to our apartment and Hannah's school, was actually worse than central Hong Kong!   Which is consistent with the current pollution being from factories in the mainland rather than domestic sources in Hong Kong.   For most of rest of the year pollution in Shatin is lower than in Hong Kong or Kowloon because it is isolated from the main urban center.

AQICN Tues 27-Jan 3pm

At the same time, the Hong Kong government official air quality health indicator (AQHI) presented a more positive picture, as it almost always does.  The health risk in most areas was rated as 'moderate' - 4 or 5 on a scale of 1-11.    Nevertheless even by its lower standards the AQHI data indicates a health problem:   "the number of days deemed dangerous to health using Hong Kong's AQHI stands at about 30 per cent. (Hong Kong's ambient air guidelines are less stringent than those of the WHO.)"  (source : scmp)

AQHI  Tues 27-Jan 3pm

The AQHI measure has was introduced in 2014 along with new Air Quality Objectives.   For example, the objectives set a limits for PM 10 and PM 2.5 over a 24 hour period at 100μg/m3 and 75μg/m3 respectively, and an annual average at 50 μg/m3 and 35 μg/m3.  (AQO link).

This doesn't seem very ambitious:  the annual PM2.5 target is same as for mainland China (35 μg/m3) and much higher than other rich countries' such as EU (25), Japan (15), US (12), and Australia (8).   I believe the WHO limit is 10.   The alignment with China suggests that the Hong Kong health department did not enjoy a 'high degree of autonomy' in setting the target!

Also the target is not much better with the current air quality!  The latest Air Quality Report (2013) reports average PM10 / PM2.5 of about 55/35 respectively for Central and 45/30 for Shatin (AQ Report link) vs the target of 50/35.

Fri 30-Jan 5pm IFC and Central from ICC

Furthermore, meeting the current Air Quality Objectives would not deliver 'safe' air.    "The IARC and WHO designate airborne particulates a Group 1 carcinogen. Particulates are the deadliest form of air pollution due to their ability to penetrate deep into the lungs and blood streams unfiltered, causing permanent DNA mutations, heart attacks, and premature death.  In 2013, a study involving 312,944 people in nine European countries revealed that there was no safe level of particulates and that for every increase of 10 μg/m3 in PM10, the lung cancer rate rose 22%. The smaller PM2.5 were particularly deadly, with a 36% increase in lung cancer per 10 μg/m3 as it can penetrate deeper into the lungs." (wiki link)

Fri 30-Jan 5pm  East Hong Kong Island and Sunset

Of course regardless of the targets, what really matters is progress in reducing actual pollution.   The main sources of pollution are both regional and local:  factories and power plants of the Pearl River Delta, shipping, and domestic vehicles and power plants.

Fri 30-Jan 5pm Sunset over Hong Kong Harbour andLantau

In all these areas action to control pollution lags far behind the US and Europe - standards for vehicle pollution and shipping pollution are much laxer, and Hong Kong still relies on coal for much of its electricity etc. etc.  Some critics argue that this is due to powerful interests in various sectors whose profits benefit from lax controls.   

AQICN Fri 30-Jan 5pm

It is sometimes argued that Hong Kong can't be too unhealthy because HK residents have enjoyed one of the highest life expectancies in the world.  But I wonder if the full effects of the increased pollution have yet to show up in the life expectancy data.  I was interested to read a report in todays SCMP  that lung cancer is the most common cause of cancer deaths in Hong Kong and has increased 30% in the past 10 years.  Although the official commentary from the Department of Health blamed lifestyle factors, and did not mention pollution at all.  

On the positive side the government has done a great job of expanding public transport, has improved pollution monitoring, and from 2014 has a Clean Air Plan (link) with firm actions to reducing the main sources of pollution, albeit on a rather unhurried time-table.   E.g. subsidizing the phasing-out of the dirtiest diesel vehicles.   So we can hope that the air will become somewhat better over the next 5 years.

Wed 11-Feb 5pm  IFC from ICC

Postscript:  11-Feb.   Very bad air today with a lot of haze.  My eyes became itchy when I walked outside.  Both the AQICN and the official AQHI measures rate the air as very unhealthy this evening.

Hong Kong AQICN Wed 11-Feb 9pm

The Hong Kong AQICN is 211, which is as high as Ive seen it.   Whats it like in other cities right now?  Shenzhen 200, Guangzhou (Canton) 227  and Shanghai 173, although Beijing is enjoying clear air tonight at 38.   London (Trafalgar Square) and Tokyo  (Shibuya) are both relatively high by their standards at 113 and 117 respectively.

Shatin AQICN 11-Feb 9pm

I was interested to see that this week's edition of the Economist has not one but three  articles on air pollution!  They quote a study which estimated that particulates pollution has cut life expectancy in northern China by about 5.5 years.   And in the SCMP a Greenpeace was study was reported (link) to estimates that pollution in 31 Chinese cities now kills more people than smoking!

Official AQHI 11-Feb 9pm

What can we do, personally?   Well at home we are running HEPA air purifiers at home (Alen Paralda).   Outdoors wearing face-masks outside is apparently not much use.  Masks are somewhat effective against PM10 but only as much as breathing through your nose.   Most masks are ineffective for the more dangerous PM2.5,  and the masks that are effective are difficult to breath through, putting strain on your heart etc.     I've been a habitual mouth-breather due to childhood asthma, so Im trying to change my habit to nose-breathing.   And Im writing a letter to my MP!