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Indoor Air

Exposure to pollution in Hong Kong is worst in the home, study reveals

It’s not just on the city’s streets where we are at risk from dangerous PM2.5 particulates – three-quarters of daily personal exposure is indoors

Your home may be your refuge in Hong Kong, but not from air pollution. It’s probably worse.

Exposure to PM2.5 particulates small enough to lodge deep in the lungs and most harmful to human health have been found to be just as high – or higher – inside people’s homes as they are outdoors or during the commute to work on an average weekday.

A two-year study by think tank Civic Exchange and City University, funded by investment bank Morgan Stanley, found that most urban dwellers are exposed to concentrations of PM2.5 during their daily commute that are almost always above average limits set by the World Health Organisation, and generally above readings at the nearest air quality monitoring station.

Breathe easier, Hong Kong is on course to hit global air pollution target

While the Environmental Protection Department’s 16 stations can monitor and assess ambient and roadside air quality across districts, the study fills a relatively wide gap in statistics on individual-level exposure to pollution in different “micro-environments”.

Co-author Dr Zhi Ning reported finding that people were exposed to air pollution risks not just outdoors but also indoors at home or the office.

“Your 24 hours are spent in different environments,” the City University air pollution expert said. “You may think that even if its very polluted outside, you are more safe inside. But it really depends on what that indoor environment is like.”

The researchers employed 73 volunteers who carried lunchbox-sized “personal exposure kits” fitted with sensors and GPS, 24 hours a day for a year around the city.

They found that most spent more than 85 per cent of each weekday indoors, which broke down to 42 per cent of the day at home, 34 per cent in the office, 4 per cent commuting and 11 per cent outdoors or in other indoor areas.

Homes were found to contribute 52 per cent of an individual’s personal exposure to PM2.5 compared with 13 per cent for offices, 4 per cent while commuting, 18 per cent outdoors and 14 per cent in other indoor areas.

The average PM2.5 concentration measured in homes – 42.5 micrograms per cubic metre – was three to four times lower than outdoors but slightly higher than while commuting and three times higher than in the office.

Factors for the PM2.5 build up in homes, Ning surmised, could range from cooking and the type of gas used to proximity to a construction site or smoking tobacco. And this was exacerbated by poor ventilation and dirty air filters. Offices tended to have better ventilation systems. Flats on lower floors were also exposed to more pollution.

But Ning found little correlation between personal exposure and district pollution. A person who spent more time in better ventilated indoor areas in heavily polluted Sham Shui Po, for example, could have a lower exposure to PM2.5 than the station reading and vice versa.

“Right now we only rely on [the department’s] data but they only provide a general, ballpark figure,” Civic Exchange research fellow and co-author Simon Ng Ka-wing said.

“It is important to know how much air pollution we are exposed to on a personal level. This would allow us to make better decisions as to when to go or not to go somewhere.”

The study recommended the government do more to promote better indoor air quality in homes and implement a comprehensive management programme.

A government spokesman said: “The EPD has been conducting promotional and educational activities, including exhibitions and seminars, to promote practices to achieve good indoor air quality.”

Additional reporting by Brian Wong

300 million children breathe heavily toxic air: UNICEF

Some 300 million children live with outdoor air so polluted it can cause serious physical damage, including harming their developing brains, the United Nations said in a study released Monday.

Nearly one child in seven around the globe breathes outdoor air that is at least six times dirtier than international guidelines, according to the study by the UN Children’s Fund, which called air pollution a leading factor in child mortality.

UNICEF published the study, “Clear the Air for Children,” a week before the annual UN climate-change talks, with the upcoming round to be hosted by Morocco on November 7-18.

The agency, which promotes the rights and well-being of children, is pushing for world leaders to take urgent action to reduce air pollution in their countries.

“Air pollution is a major contributing factor in the deaths of around 600,000 children under five every year, and it threatens the lives and futures of millions more every day,” said Anthony Lake, executive director of UNICEF.

“Pollutants don’t only harm children’s developing lungs. They can actually cross the blood-brain barrier and permanently damage their developing brains and, thus, their futures. No society can afford to ignore air pollution,” Lake said.

Toxic air is a drag on economies and societies, and already costs as much as 0.3 percent of global gross domestic product, the broad measure of economic activity, UNICEF said.

Those costs are expected to increase to about one percent of GDP by 2060, it said, as air pollution in many parts of the world worsens.

UNICEF points to satellite imagery which it says confirms that about two billion children live in areas where outdoor air pollution exceeds minimum air-quality guidelines set by the World Health Organization.

The air is poisoned by vehicle emissions, fossil fuels, dust, burning waste and other airborne pollutants, it said.

South Asia has the largest number of children living in such areas at about 620 million, followed by Africa with 520 million and the East Asia and Pacific region with 450 million.

The study also looked at indoor air pollution, typically caused by burning coal and wood for cooking and heating.

Together, outdoor and indoor air pollution are directly linked to pneumonia and other respiratory diseases that account for almost one death in 10 in children under the age of five, or nearly 600,000 children, making air pollution a leading danger to children’s health, UNICEF said.

The agency noted that children are more susceptible than adults to indoor and outdoor air pollution because their lungs, brains and immune systems are still developing and their respiratory tracts are more permeable.

Children breathe twice as quickly as adults and take in more air relative to their body weight.

The most vulnerable to illnesses caused by air pollution are children living in poverty, who tend to have poorer health and little access to health services.

– Better protect children –

To combat these noxious effects, UNICEF will call on the world’s leaders at the UN’s 22nd meeting on climate change in Marrakesh, known as COP22, to take urgent action to better protect children.

“Reducing air pollution is one of the most important things we can do for children,” UNICEF said in its report.

At the government level, UNICEF said steps should be taken to reduce fossil-fuel emissions and increase investments in sustainable energy and low-carbon development.

The agency, noting that air quality can fluctuate rapidly, also called for better monitoring of air pollution to help people minimize their exposure.

Children’s access to good-quality healthcare needs to be improved and breastfeeding in the child’s first six months should be encouraged to help prevent pneumonia.

Policymakers should “develop and build consensus on children’s environmental health indicators,” the report urged.


Hidden danger: keeping your house clean can harm your kids’ health, Hong Kong study finds

Researchers suggest limiting frequent exposure to chemicals to avoid rhinitis

Blocked noses, headaches, sneezing and other allergic symptoms among children in Hong Kong could be caused by household cleaning products, an alarming news study
has found.

Research by Chinese University of Hong Kong – the first to examine such products’ health effects on children in Asia – found that frequent use of the chemicals at home could increase the risk of children having rhinitis, or inflammation of the lining of the nose, by between 29 and 97 per cent.

The condition affecting up to 50 per cent of local primary school students could impair their quality of life as well as their scholastic performance, the researchers warned.

How living near a landfill can be harmful to health, especially for children ( Dr Xiangqian Lao, an assistant professor at Chinese University’s school of public health and primary care, said the findings suggested it was “necessary to develop healthier cleaning products”.

“Parents are also recommended to prevent triggering rhinitis in children by reducing their exposure to chemical cleaning products at home,” he said.

The three-year study surveyed over 2,299 students from 21 local primary schools on the use of 14 cleaning products at home.

It found the youngsters were most often exposed to kitchencleaning products, followed by floor-cleaning and bathroomcleaning products.

Children with the highest level of exposure to cleaning products – tallying more than 3.2 hours per week – had a 29 per cent higher risk of experiencing occasional rhinitis, a 97 per cent higher risk of frequent rhinitis, and a 67 per cent higher risk of persistent rhinitis.

Every additional hour of exposure was associated with a 2.1 per cent higher risk of occasional rhinitis, a 3.6 per cent higher risk of frequent rhinitis, and a 1.2 per cent higher risk of persistent rhinitis.

The results suggested the ensuing health effect could be due to one’s total exposure to an array of cleaning products rather than to just a single type of product.

But no such associations were observed regarding the use of clean water for daily household cleaning.

Hong Kong children wait more than a year for mental health treatment as list increases to 27,000 (The researchers suggested that common household cleaning products contained harmful chemicals, including propylene glycol, ethylenediaminetetraacetic acid or EDTA, and volatile organic compounds.

They said their study was in line with others noting the adverse effect of cleaning products, especially relating to various respiratory health outcomes like infections and

The study was published this month in The Journal of Allergy and Clinical Immunology.

According to the World Health Organisation, allergies affect up to 40 per cent of the world’s population, and the rate is rising, with allergic rhinitis being the most common.

Hong Kong indoor air pollution so bad it could be making you chronically ill, tests show

Pollutant levels up to 1,250 per cent higher indoors than outdoors, and PM2.5 fine-particle pollution worse than beside some of the city’s busiest roads, shock research by Baptist University finds

The air pollution inside some Hong Kong homes is worse than beside some of the city’s busiest roads, tests show. And it could be making the homes’ occupants chronically ill, worried scientists say.

Levels of small-particle pollution, known as PM2.5, that can lodge deep in people’s lungs were on average nearly 10 per cent higher indoors than the highest level found outdoors.

Levels of volatile organic compounds (VOCs) – carbon-based chemicals that easily evaporate at room temperature – were, on average, over 1,250 per cent higher in kitchens than outdoors. And the median level of VOCs in 27 of 32 homes tested exceeded the recommended maximum level for Hong Kong offices.

One of the researchers said indoor air pollution – from perfumes, cleaning products and cooking fumes – turned the average Hong Kong home into a “mini chemical warehouse”.

Studies in other countries have also found indoor air pollution is higher than that outdoors. The situation in Hong Kong could be aggravated by factors such as high-rise living, subdivided flats, a lack of windows and ventilation in some rooms, and restaurants occupying ground-floor premises in residential buildings, one of the researchers said.

The research was conducted by Baptist University’s biology department and household appliances manufacturer Dyson. Air quality was tested in 32 homes, with samples taken in their living rooms and kitchens, and directly outside these rooms.

The tests showed the median level of indoor VOCs in most of the homes tested was 345 parts per billion (ppb) compared with 95.5ppb outside the flats. Hong Kong’s Environmental Protection Department says VOCs should not exceed 200ppb in offices. Kitchen VOC levels were far higher.

“VOCs are consistently higher indoors than outdoors. Even so, the research found that the kitchen VOCs are on average 1,258 per cent higher than outdoors,” said Baptist University’s Dr Lai Ka-man, who led the research in March.

The researchers’ report, citing the US US Environmental Protection Agency, says: “Toxic fumes released from cleaning solvents, deodorants and scented candles are some of the most common indoor air pollutants. Other major indoor air pollutants include gases from cooking, mould, pet hair, pollen and allergens.”

The scientists tested for two classes of particulate matter (PM), fine particles resulting from combustion such as that by vehicle engines and power stations. In the home, particulate matter can be produced by cooking and by smoking tobacco. Exposure to excessive levels can lead to allergic reactions of the lower respiratory tract, such as asthma, and to strokes and heart attacks, according to health professionals.

Readings were also taken at seven outdoor locations around the city.

The tests found micro-particle pollution, or PM0.1, was on average 68.5 per cent higher inside homes than outside. (PM0.1 is one-thousandth the diameter of a human hair, and can penetrate the lungs and enter the bloodstream.)

“The highest outdoor PM0.1 was 94 million particles per litre (ppl), recorded at the junction near the Sogo department store in Causeway Bay. The highest indoor sample was a worrying 46.8 per cent higher, at 138 million ppl [recorded in a Tai Wo flat in the New Territories]”, Lai said.

Hong Kong has no guidelines on recommended levels of indoor particulate matter, but it is indicative that outdoor readings in busy roadside areas often reach dangerous levels on the air pollution index – levels that, ironically, trigger warnings to residents with respiratory problems to stay in their homes.

Surprisingly, Lai said, indoor levels of PM2.5 were higher than outdoors. Indoor readings were on average 9 per cent higher than the highest reading recorded outdoors, of 369 ppl, outside Sogo in Causeway Bay; the PM2.5 reading in Nathan Road, Mong Kok, one of the city’s busiest urban roads, was 363ppl.

Science Daily: Air Pollution Puts the Health of School Children at Risk

from Science Daily:

A recently completed study by The Hong Kong Polytechnic University (PolyU) on 310 children in 12 schools across the territory found the air pollution level along the traveling routes from home to schools and particulate levels outside school both at a very high level, and most of the school children have lung function weaker than the predicted levels.

The study was done by Dr Hung Wing-tat, Professor Frank Lee Shun-cheng and Ms Lee Sin-hang of the University’s Department of Civil and Environmental Engineering. They found that children in only two out of twelve surveyed schools have lung function better than predicted levels, whilst children in the remaining ten schools have lung function weaker than the predicted levels.

The study also found that carbon dioxide levels inside five of the twelve school classrooms are found to be higher than the stipulated good class level of HK Indoor Air Quality (HKIAQ), probably due to the presence of full class of students within the monitoring period.

PolyU researchers also collected information about the traveling patterns of these 310 school children and then monitored the air pollution level along the traveling routes of the subjects. About 48% of school children go to school on foot, the second most popular choice is the school bus (24%). They found that both PM10 and PM2.5 levels in various transportation modes are high.

It is worth noting that PM2.5 levels far exceed the stipulated health levels of WHO safety level of 75 µg/m3 (24 hours average) and the situation in school buses is worst. The total volatile organic compound (TVOC) levels in all transportation modes far exceed the good class level of HKIAQ and the situation in school buses is worst.

The study also found that allergic rhinitis is very common among local school children (ranging from 13% to 59.3% in schools). Allergic rhinitis is found to be related to tobacco smoking household, incense burning at home and molds at home. However, molds and mildews are common (25.9% to 62.5%) in household because of the humid weather.

Children in tobacco smoking households also have significantly poorer lung function. The study found high percentages of smokers in the households, ranging from 25.0% to 69.6%. One of the key findings is that Lung function of school children, FVC and FEV1 are found to be negatively co-related with PM10 levels in classrooms at 0.05 significant levels. It is critical to suppress the level of PM10 in classroom to protect the health of school children.

Pulmonary function tests were conducted on surveyed school pupils to assess their lung function, which was measured by a spirometer in this study.

The above story is based on materials provided by The Hong Kong Polytechnic University.

19 Nov 2013

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Bad atmosphere

bad-airLast updated: March 16, 2010

Source: South China Morning Post

Life has not been the same since my meeting on Friday with indoor air consultant George Woo. I had always thought of air pollution in terms of grey skies, cross-harbour visibility and diesel fumes. The roadside readings are bad today, so I must stay off the streets as much as possible, my subconscious would tell me. Horror of horrors: I just learned that sitting at an office desk – what most of us do for our working day – can be as bad, perhaps worse, for our health.

Woo has been campaigning for five years to get people to think about pollution in this way. I phoned him after a friend, just diagnosed with allergic bronchitis, wondered whether his cough and itchy eyes could have something to do with the quality of air in his office on Hong Kong Island. The irritations seemed to be worse at peak traffic times. Then my friend smuggled the specialist, his assistant and two pieces of hand-held equipment into the building at 6.30pm for an hour of tests.

Bus Air Con Unhealthy, Say Greens

Joyce Ng – Updated on Mar 09, 2009 – SCMP

A green group has called for the return of buses without air conditioning to improve ventilation after finding the air inside some air-conditioned buses had carbon dioxide concentrations four to eight times higher than that in average outdoor air.

The higher concentrations inside buses could encourage the spread of illnesses such as influenza among passengers, Green Sense president Roy Tam Hoi-pong said.

His group in December conducted half-hour measurements on eight KMB buses and one New World First bus, which were all air-conditioned. The tests found carbon dioxide concentrations ranging from 824 to 3,144 parts per million (ppm), the average being 1,643ppm. The highest was recorded on a KMB route 15 bus running from Lam Tin to Hung Hom.

None of the readings exceeded the Environmental Protection Department’s air quality guideline for air-conditioned buses, which regards an hourly average below 2,500ppm to be good and anything below 3,500ppm not harmful to health.

However, Mr Tam and Medical Association vice-president Alvin Chan Yee-shing said the guideline was too loose. Outdoor air normally had a concentration of 400ppm to 500ppm, Mr Tam said. “The higher the concentration, the poorer the ventilation inside the bus. It makes passengers feel tired and dizzy.”

Air-conditioned buses also wasted 5 to 10 per cent of their fuel driving the air-conditioning system, he said.

Dr Chan said the result was “alarming”, especially in the flu season; viruses would linger in stagnant air and spread among passengers.

A survey of 517 passengers by the group found 65 per cent supported use of non-air-con buses in winter.

KMB principal engineer Kane Shum Suet-hung said more than half the company’s fleet had electronic air cleaners to filter out contaminants. He said the opening and closing of doors brought in, on average, 8,000 cubic metres of fresh air per hour.

A Fresh Start

Updated on Mar 05, 2009 – SCMP

Some things will need to change as Hong Kong people demand a more healthy living environment. The sooner our government and politicians respond to this, the sooner their popularity will rise. Even during tough economic times, people still want to protect their health. Inaction on this issue cannot be excused simply because “it costs more”.

A headline in the Sunday Morning Post sounded a warning: “Parents question decision to build MTR air vent next to school”. Parents of students attending Bonham Road Government Primary School are fighting the railway operator’s plan to site a ventilation shaft next to the school. The company and government say the shaft acts like a window to improve air exchange and will not spew out pollution.

What is interesting is the concern of parents. A few years ago, such a protest would probably not have happened. Today, people are far more concerned about public health. They are asking questions and demanding answers.

Parents should focus on how far away schools are from major roads; vehicle emissions are a health hazard for everyone, but especially children.

In the US, a school sited within 400 metres of a highway is considered within an air-pollution danger zone. If we were to apply this standard to Hong Kong, many of our schools situated right by busy roads with very high daytime pollution levels would not pass muster. Equally threatening to health is the undesirable “street canyon effect” that traps pollution between tall buildings.

Planners and officials might protest that it is impossible to ensure schools in Hong Kong are sited further away from busy roads because of the high urban density, but this assumption should not be taken at face value. We should at least ask how, in a city like ours, we can protect public health, especially of youngsters whose physical development can be impaired by pollution.

Children are not just miniature adults: they eat, drink and breathe at much higher rates; their growing bodies more readily absorb contaminants; and their developing immune systems make them more prone to diseases and disorders caused by exposure to toxins. Polluting emissions near schools, where children spend many hours a day, pose a huge threat to students’ health. Although the science is clear, we have not yet taken public health into account when planning our city.

Turning on air filter systems indoors will help, to a point. But, if the overall air quality is poor, all of us suffer.

In such a dense and built-up city, shouldn’t the attitude be “we need to work harder to minimise health risks” rather than “we can’t do much about it”? The political will of our leaders is paramount. Very little will change from a “business-as-usual” approach. Much more can be done if they adopt the Hong Kong “can-do” attitude our officials so loudly crow about when it comes to business matters.

For Hong Kong to have a chance to be a healthier city, the Development Bureau (which is in charge of urban planning), the Transport and Housing Bureau and the Environment Bureau first need to work together, rather than stay in their own bunkers. The heads of these policy bodies need to know, through legislation, what Hong Kong’s priorities are.

Laws such as the Air Pollution Control Ordinance need to be overhauled so that public health becomes the clear driver for planning and emissions control. Air quality standards must also be drastically tightened to make them at least consistent with modern health standards in science.

The government will argue that it is “reviewing the standards” but, if the whole of the government is not given a unifying vision and mission to make health a top priority through strong policy and laws, it won’t be enough.

Parents arise! We owe nothing less to our children.

Christine Loh Kung-wai is chief executive of the think-tank Civic Exchange.