Airborne particulates in Hong Kong – health risks

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    Airborne particulates have been in the news in Hong Kong again, as the air is so thick with them that even clear skies are whitish rather than blue (hah! – so much for the government's Action Blue Sky Campaign – launched w fanfare; seems to have vanished amidst the smog); and HK Chief Executive Donald Tsang expressed the view that while they do impact visibility, the particulates may not affect human health!

    [June 2012 update: Donald Tsang about to leave office, in shameful manner given his propensity for expensive overseas trips and utter lack of empathy for most Hong Kong people; failed to make good on his promise to introduce new AIr Quality Objectives before leaving office. I'll put more info on air pollution and health in other threads, including Dirty Air is Dangerous Air.]

    This was a curious opinion on Donald's part, since the EPD notes – in report on HK air quality during 2005:

    RSP [Respirable Suspended Particulates] at high levels may cause chronic and acute effects on human health, particularly the pulmonary function, as they can penetrate deep into the lungs and cause respiratory problems. These effects are enhanced if high RSP levels are associated with higher levels of other pollutants, such as SO2. The smaller particulates in RSP have a major impact on visibility.

    Well, Mr Tsang, even though you perhaps don't read your own government's reports, I hope you'll have time to review this thread, maybe contribute a post or two, for I'll try n find some info on airborne particulates and associated health risks.

    First: there are various sources of these particulates, but main concerns are with particulates from vehicle exhausts, power stations (and factories). Larger particulates tend to be filtered by our noses; but smaller ones – below 10 microns (10 micrometres) – can pass on through respiratory tracks, even penetrating deep into our lungs (and lung tissues). These Respirable Suspended Particulates (RSP) are classified by World Health Organisation into two types: PM10, for particles 2.5-10 microns; and PM2.5, for those smaller than 2.5 microns. In Hong Kong, seems Environmental Protection Department only considers all RSPs, below 10 microns. WHO notes that studies have been consistent in showing RSPs have health impacts, primarily on respiratory and cardiovascular systems. And, impacts found at levels even close to "background" levels (ie without exhaust fumes etc) – so there isn't really a fully safe lower limit for RSPs. –

    This info from 2006 air quality guidelines (pdf) file, available from WHO site at: Air quality guidelines

    Through assessing several studies, the WHO has suggested the following Air Quality Guideline for Respirable Suspended Particles (PM10) – 20 microgrammes per cubic metre WHO guidelines note:

    These are the lowest levels at which total, cardiopulmanary and lung cancer mortality have been shown to increase with more than 95% confidence in response to long-term exposure to PM2.5.

    So, how does Hong Kong fare? Not well at all. Our Air Qualilty Objective is 55 μg/m 3 – almost three times the new WHO guideline. In 2005, even this modest objective was exceeded at six general and three roadside stations; and all stations – including Tap Mun, well outside the city, at mouth of Tolo Channel, recorded RSP at levels more than double those of the new WHO guideline. The worst monitoring station for RSP during 2005 was in Causway Bay, with a whopping annual average of 84 μg/m 3. [2005 report info, was available from Air Quality Reports[/url] ] That's well above the 70 μg/m 3 of the WHO's Interim target-1 for RSP reduction: at around this level, according to the WHO: These levels are associated with about a 15% higher long-term mortality risk relative to the AQG level. The worst one-day average for RSP in 2005 was recorded in Tung Chung, with 217 μg/m 3.


    It appears that particulates from vehicles may be among causes of ischemic heart diseases (in which heart tissue may receive too little blood).
    Can We Identify Sources of Fine Particles Responsible for Exercise-Induced Ischemia on Days with Elevated Air Pollution? The ULTRA Study


    From US Environmental Protection Agency site:

    Batteries of scientific studies have linked particulate matter, especially fine particles (alone or in combination with other air pollutants), with a series of significant health problems, including: Premature death; Respiratory related hospital admissions and emergency room visits; Aggravated asthma; Acute respiratory symptoms, including aggravated coughing and difficult or painful breathing; Chronic bronchitis; Decreased lung function that can be experienced as shortness of breath; and Work and school absences.


    Wisconsin Dept of Natural Resources notes:

    Some of the smallest particles, called respirable particulates, lodge in the lung capillaries and alveoli, causing the following effects: Slowing down the exchange of oxygen and carbon dioxide in the blood, causing shortness of breath. Straining the heart, because it must work harder to compensate for oxygen loss. The people most sensitive to these conditions include those with heart problems, or respiratory diseases like emphysema, bronchitis and asthma. The elderly and children are also very sensitive. The adverse health effects from particulate matter exposure are often not immediately noticed. Particulates can accumulate in the lungs after repeated, long-term exposure causing respiratory distress and other health problems.

    Particle Pollution: Total Suspended Particulates

    from Ontario Ministry of the Environment:

    The greatest effect on health is from particles 2.5 microns or less in diameter. Exposure to fine particulate matter has been associated with hospital admissions and several serious health effects, including premature death. People with asthma, cardiovascular or lung disease, as well as children and elderly people, are considered to be the most sensitive to the effects of fine particulate matter. Adverse health effects have been associated with exposure to PM2.5 over both short periods (such as a day) and longer periods (a year or more). Fine particulate matter is also responsible for environmental effects such as corrosion, soiling, damage to vegetation and reduced visibility.

    Fine Particulate Matter

    Post edited by: Martin, at: 2006/10/31 17:43


    A briefing prepared for the World Bank notes:

    The PM damage to lung defenses manifests itself in the form of health effects such as acute respiratory infection (both upper and lower respiratory tract infections), chronic obstructive lung disease (especially bronchitis), asthma attacks, cardiovascular disease, and lung cancer. Further, recent research has increasingly shown that particles can also affect other parts of the body, including the nervous system, by physically moving out of the airways and into the blood stream [4]. Thus particle deposition in airways can set off a chain of events, potentially affecting parts of the body other than just the respiratory tract.

    As can be expected, the changes in the body are likely to be more severe in cases where the body’s defenses are already weak or previously damaged. Hence, certain population subgroups, such as the elderly, children, and individuals with existing respiratory or cardiovascular diseases, are at increased risk from exposure to PM.

    pdf file: The Science of Health Impacts of Particulate Matter [which was] available from South Asia Urban Air Quality Management – Improving health for all urban populations, begins:

    South Asian cities record some of the highest levels of outdoor particulate pollution worldwide. Scientific research over the last two decades has demonstrated that particulate matter is the major pollutant of concern from the health perspective. Current research is focusing on questions relating to particulate matter characteristics such as size, number, and composition, and the mechanisms by which it causes health impacts. This briefing note presents the current understanding of the answers to those questions.

    Post edited by: Martin, at: 2006/10/31 21:10


    I’ve done an article on the site, On smoggy days, can we clean the air indoors? – seems that using air purifier with a HEPA (high efficiency particulate air) filter could be worthwhile.


    So what brands in Hong Kong are available to the public… does Fortress have a good selection? Otherwise I shall pop into my local electrical convenience store in Sai Kung and see what’s on offer.


    Only Sharp – three models – and one by Whirlpool, in the Fortress store I tried (Central). Got a Sharp FU-P60S – after first having a look in the store, then heading home and doing a bit of reading around on Internet. Reviews for this and/or related models looked good, with a few people reporting decreases in allergies etc (in US; maybe from some household stuff like dust mites?).

    Info on Sharp site: FU-P60S – says it’s 99.97% efficient vs particles of 0.3 microns, which may mean fair numbers of even tinier particles get through. Cost HK$2500, using HSBC card (bit of discount): so I hope it works! (Does tend to have orange lamp – for dirty air – on as start operating; but goes to green, for clean, after a few minutes.) Heard of a purifier costing HK$9600 (ouch!) in Bumps to Babes, down from over HK$12,000. For dough like that, gotta hope it also does the vacuuming and ironing…


    From the Independent:

    Researchers have found that young people growing up in homes within 500 metres of a major road suffer significant damage to their lungs from exhaust fumes.

    The study, conducted at the University of Southern California, is the latest to show that air pollution increases the risk of respiratory disease. But few studies have examined its effect on lung growth in children.

    The authors say carbon, nitrogen dioxide and ultrafine particulates – tiny particles that can penetrate deep into the lungs – are all increased near roads and could account for the damage. Diesel exhaust has been shown to be particularly damaging.

    Stephen Holgate, professor of immunopharmacology at the University of Southampton, said the study added to evidence that exhaust fumes damaged lung development in children "probably in the first five to eight years of life".

    He said: "Reduced lung function in childhood is a known risk factor for the development and worsening of asthma in children and the development of chronic obstructive pulmonary disease later in life." He added: "The study adds to the conclusions made in a World Health Organisation report on the health effects of pollution in children, published in 2006, and emphasises the importance of continuing strategies to reduce pollutant hot spots as well as reducing overall air pollutant exposure."

    Children growing up near roads suffer serious damage to lungs


    From WebMD Medical News:

    Air pollution is a much bigger factor in death from heart disease or stroke than has previously been recognized, according to findings from one of the largest studies ever to examine the issue.

    Researchers followed close to 66,000 women — aged 50-79 — living in 36 cities. All the women were enrolled in the ongoing health study, the Women’s Health Initiative.

    After adjusting for other risk factors for heart disease and stroke, they found that air quality was a strong predictor of heart disease and stroke risks — and an even stronger predictor of death from heart disease or stroke.

    Fine particulate air pollution — caused primarily by vehicle exhausts, coal-fired power plants, and other industrial sources — was the sole type of air pollution associated with increased risk.

    Fine particulate air pollution is measured in micrograms per cubic meter. According to the EPA, fine particles of 2.5 micrometers or smaller are in smoke and haze. They can occur because of gases from industrial plants and cars.

    The 36 cities represented in the study had average levels of this type of pollution ranging from 3.4 micrograms per cubic meter (in Honolulu) to 28.3 (in Riverside, Calif.), write the researchers.

    According to the EPA, in 2005, Los Angeles, Birmingham, Detroit, and Pittsburgh were among the cities with the most fine particulate air pollution, with pollution levels ranging from 18 to 21 micrograms per cubic meter.

    Tucson, Ariz.; Miami; and Reno, Nev., were among the cities with the cleanest air, with levels below 10.

    After adjusting for other heart disease and stroke risk factors, Kaufman and colleagues concluded that each 10-unit increase in air levels of fine particulate matter was associated with a 76% increase in the risk of death from cardiovascular disease.

    Higher long-term exposure to air pollution was also linked to an increased risk for developing cardiovascular disease.

    Environmental epidemiologist Douglas Dockery, ScD, of the Harvard School of Public Health, tells WebMD that it is now clear that fine particle air pollutants poses a unique risk to health, but the reason for this is not so clear.

    "It may be their chemical composition, their size, or their ability to transport other pollutants deep into the lungs," he says. "There is a lot of research going on right now attempting to figure this out."

    Dockery says the scientific evidence supporting tighter restrictions on fine particle pollution levels is now overwhelming.

    Air Pollution Linked to Heart Deaths
    Risk May Be Higher Than Previous Studies Suggest

    Via googling, I find that a recent study over 4-month period showed Hong Kong and Guangdong exceeded highest levels of fine particulates for places in the US study: Guangdong had sites way exceeding it. (Must be many more heart attacks and strokes in dirtiest Guangdong places than should be the case: but what can people do about this, esp when so much money being made?)

    The 4-month average fine particulate matter concentration ranged from 37 to 71 ug/m3 in Guangdong province and from 29 to 34 ug/m3 in Hong Kong. Main constituents of fine particulate mass were organic compounds (24-35% by mass) and sulfate (21-32%).

    Source areas and chemical composition of fine particulate matter in the Pearl River Delta Region of China


    Just heard on radio news of results of Hong Kong study showing that numbers of hospital admissions – especially for chronic conditions – rise with amounts of air pollutants.
    Ozone having the most impact.

    Hopefully, will find more info on this shortly, and amend this post.


    Hardly seems surprising really, though best to get forensic evidence I guess. It seems that this year’s Marathon runners again suffered directly and quite clearly as a result of airborne pollutants – runners in the later events suffering most as the pollutants count rises as the day progresses.


    Well, Donald Tsang may still like to figure that air pollution is mainly about whether we have nice views, but evidence mounts re dangers.
    Inc in new report from Europe:

    The latest in a series of assessments of the pan-European environment published by the EEA over the past 15 years, the report assesses environmental progress in 53 countries

    Despite some success with air pollution, current levels — mainly nitrogen oxide, fine particles and ground-level ozone — are estimated to shorten average life expectancy in Western and Central European countries by almost a year and to threaten the healthy development of children.

    Pollution Cuts Life Expectancy, Threatens Child Development In Europe


    Hi Donald – you are reading this right? You are interested in learning of airborne particulates actually threaten health, rather than being mainly a problem with making views less pretty, as you’ve claimed?
    Well, read on – here, from article by Science Daily.

    A new academic study led by UCLA researchers has revealed that the smallest particles from vehicle emissions may be the most damaging components of air pollution in triggering plaque buildup in the arteries, which can lead to heart attack and stroke.

    The scientists identified a way in which pollutant particles may promote hardening of the arteries ¡X by inactivating the protective qualities of high density lipoprotein (HDL) cholesterol, known as "good" cholesterol.
    A multicampus team from UCLA, the University of Southern California, the University of California, Irvine, and Michigan State University contributed to the research, which was led by Dr. Andre Nel, UCLA’s chief of nanomedicine. The study was primarily funded by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency (EPA).

    "It appears that the smallest air pollutant particles, which are the most abundant in an urban environment, are the most toxic," said first author Dr. Jesus Araujo, assistant professor of medicine and director of environmental cardiology at the David Geffen School of Medicine at UCLA. "This is the first study that demonstrates the ability of nano-sized air pollutants to promote atherosclerosis in an animal model."
    Nanoparticles are the size of a virus or molecule ¡X less than 0.18 micrometers, or about one-thousandth the size of a human hair. The EPA currently regulates fine particles, which are the next size up, at 2.5 micrometers, but doesn’t monitor particles in the nano or ultrafine range. These particles are too small to capture in a filter, so new technology must be developed to track their contribution to adverse health effects.
    "We hope our findings offer insight into the impact of nano-sized air pollutant particles and help explore ways for stricter air quality regulatory guidelines," said Nel, principal investigator and a researcher at UCLA’s California NanoSystems Institute.

    Nel added that the consequences of air pollution on cardiovascular health may be similar to the hazards of secondhand smoke.

    Pollutant particles are coated in chemicals sensitive to free radicals, which cause the cell and tissue damage known as oxidation. Oxidation leads to the inflammation that causes clogged arteries. Samples from polluted air revealed that ultrafine particles have a larger concentration of these chemicals and a larger surface area where these chemicals thrive, compared with larger particles, Sioutas noted.

    How Ultrafine Particles In Air Pollution May Cause Heart Disease


    eRecent email from Civic Exchang

    Civic Exchange’s Latest Publication


     A Price Too High:

    Health Impacts of Air Pollution in Southern China

    10,000 deaths a year in southern China: can the region’s inhabitants afford to wait?

    New data on health costs for Hong Kong, Macao and the Pearl River Delta


    Hong Kong-based think tank Civic Exchange released a groundbreaking study today entitled A Price Too High – Health Impacts of Air Pollution in southern China. The study – conducted by leading health, science and public policy experts – reveals new regional data on the health costs of poor air quality. Annual deaths attributable to air pollution – based on 2006 data – are estimated at 10,000 in Hong Kong, Macau and the Pearl River Delta, with over 90% occurring in the Pearl River Delta. Air pollution is also responsible for 440,000 annual hospital bed-days and 11 million annual outpatient visits throughout the region.


    In money terms, the hospital bed-days, lost productivity and doctor visits associated with this health impact cost RMB 1.8 billion a year in the PRD, HK$ 1.1 billion in Hong Kong, and HK$ 18 million in Macao. Adjusted for differences in gross domestic product across the region, the health-related monetary costs of air pollution in the PRD amount to RMB 6.7 billion.


    In spite of the enormous health costs of deteriorating air quality, there is surprisingly little research in the region into the links between air pollution and poor health. According to the study, in the past 25 years only 147 such reports have been conducted for all of mainland China, with only 37 of those concerned with Southern China. The current air pollution indexes used in Hong Kong and the PRD are not merely insufficient but misleading, as they are not directly linked with health protection.



    Full report and presentation are available on Civic Exchange website:

    Full Report:
















    Civic Exchange is a non-profit public policy think tank based in Hong Kong that helps to improve policy and decision-making through research and analysis. For more information about Civic Exchange, please visit  


    From a Columbia University press release:

    Closing coal-fired power plants can have a direct, positive impact on children’s cognitive development and health according to a study released by the Columbia Center for Children’s Environmental Health (CCCEH) at Columbia University’s Mailman School of Public Health. The study allowed researchers to track and compare the development of two groups of children born in Tongliang, a city in China’s Chongqing Municipality – one in utero while a coal-fired power plant was operating in the city and one in utero after the Chinese government had closed the plant. Among the first group of children, prenatal exposure to coal-burning emissions was associated with significantly lower average developmental scores and reduced motor development at age two. In the second unexposed group, these adverse effects were no longer observed; and the frequency of delayed motor developmental was significantly reduced. The study findings are published in the July 14th Environmental Health Perspectives.

    “This study provides direct evidence that governmental action to eliminate polluting coal-burning sources benefits children’s neurodevelopment,” said Frederica Perera, DrPH, professor of Environmental Health Sciences at the Mailman School of Public Health, director of the Columbia Center for Children’s Environmental Health, and lead author of the study. “These findings have major implications for environmental health and energy policy as they demonstrate that reduction in dependence on coal for energy can have a measurable positive impact on children’s development and health – in China and elsewhere.”

    Closure of Coal-Burning Power Plant in China Directly Linked to Improved Cognitive Development in Children

    for more on study in Tongliang, in Scientific American, see: Is China’s Pollution Poisoning Its Children?

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