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Indoor Air

Guangzhou: Toxins Levels In 70% Apartments Excessive

China Daily – Oct. 8

BEIJING — Researchers have discovered about 70 percent of apartments in Guangdong’s provincial capital contained formaldehyde levels exceeding national standards, the Guangzhou Daily reported. On average, levels were 64.3 percent higher than the standard, it said.

Experts have urged local residents to avoid undertaking extensive home improvements, the newspaper reported. They also urged home-buyers to wait until their new residences pass environmental inspections before moving in. If toxicity levels exceed the standard, remedial measures should be undertaken before owners take up residence in the homes. In addition to installing ventilators and air filters, residents can grow Spider Plants, aloes and kumquats, which absorb toxins in the air. Researchers made the remarks in Guangzhou during the 4th Seminar of Sustainable Development of Guangdong Province, Hong Kong and Macao Special Administrative Regions on Monday.

Guangzhou municipal environmental monitoring center official Li Yingwen said most dwellings with indoor air pollution were constructed with substandard artificial panels and fiber boards, and poisonous paints. Some leather furniture also emitted formaldehyde.

The chemical can irritate the eyes and lungs, and even trigger asthma attacks. Long-term exposure has also been linked to leukemia. “The more luxurious the apartments are, the more likely they are to be seriously contaminated,” Li said.

The formaldehyde levels in some recently completed luxury apartments are as high as 0.6 mg per sq m – 5 times the national standard. Li urged local residents to use high-quality materials for home improvements.

In addition to formaldehyde, researchers found levels of many other toxins in Guangzhou apartments often exceeded national standards.

Local white-collar worker Liang Xiangqiong said she waited for months to move in after her apartment was completed last year to allow the airborne toxins to disperse. “But I have no idea what else to do, because it is hard to find quality interior decorating materials,” she said.

Awareness Needed Of Incense Health Risks

Updated on Aug 27, 2008 – SCMP

Burning incense at home is a traditional way for many Chinese around the world to present offerings to the gods and show devotion to them. But a new medical study has shown that worshippers may be sacrificing far more than they realise – their health. The research, published in the medical journal Cancer, finds that people who are regularly exposed to indoor incense smoke have a greater chance of developing upper respiratory tract cancer. It is the most authoritive study to date, having tracked, for up to 12 years, more than 61,000 Singaporean Chinese who are engaged in the religious practice.

Common sense ought to indicate as much, given what we know about the health risks posed by second-hand cigarette smoke and air pollution. Nevertheless, the danger has not been widely exposed. The findings need to be publicised, especially in parts of the world where the burning rituals are common in many people’s homes. Two issues are involved: product safety and lack of awareness.

Homes in Hong Kong are on average smaller than those in Singapore, so a higher level of accumulated cancer-causing substances may be trapped indoors. It is not uncommon here for families with three generations to live in the same flat, so children are especially vulnerable. There was a time when many households had small shrines set up outside the door with incense offerings. But, in recent years, tougher fire safety regulations and better estate management have forced people to put the shrines inside their homes. It would be impractical to ask people to stop an age-old tradition, but health authorities should consider introducing advertisements or public announcements to warn people of the danger and educate them on the need for proper ventilation.

Meanwhile, manufacturers should be made to produce safer incense products. Past research has shown many types of incense give off benzene and polyaromatic hydrocarbons, which can cause cancer. It ought to be possible to make safer incense that minimises or even eliminates these substances when burning. The religious practice, after all, seeks blessings from the gods for health and safety. It would be a shame to achieve the opposite.

Schools’ Air Quality To Be Checked

Will Clem – Updated on Apr 02, 2008 – SCMP

A green group has launched a campaign to monitor the air quality in schools across the city.

Clear the Air Hong Kong, an environmental pressure group, is offering schools a free assessment of pollution levels in classrooms and expert advice on how to minimise the impact on health.

The project, which the group hopes will gain the support of all primary and secondary schools, will be unveiled today but is expected to take several months to complete.

“The first phase will run until the end of June and then we plan to start up again in September,” chairman Christian Masset said. We want to include as many schools as possible.”

Mr Masset said people tended to underestimate the effect indoor air quality had on health. “We seldom think about pollution indoors,” he said. “But it has been proven that it can be responsible for various kinds of problems. Young people are most likely to be affected.”

Mr Masset said there were steps schools could take to reduce the amount of pollution getting into the classroom and this had been shown to improve students’ health.

“Educators notice that students demonstrate better performance in class and they are sick less often,” he said.

An investigation by the Sunday Morning Post last October found pollution levels were almost as high indoors as they were outdoors at three out of the four schools tested.

Indoor levels of respirable suspended particulates ranged between 76 per cent and 98 per cent of the levels in the playground at the three worst-affected schools.

Children’s Health ‘At Risk’ From Poor Indoor Air

2008-04-02 HKT 14:00 – RTHK

A green group, Clear The Air, is warning that poor indoor air quality is putting the health of Hong Kong children at risk. A spokesman for the group, George Woo, said people spend 90 percent of their time indoors, where studies had shown pollutant levels could be up to five times higher than outside. Mr Woo said that local schools lacked the knowledge to improve indoor air quality.

George Woo

Smart Air Conditioning Sensors Make KMB Buses Go Green

Scarlett Chiang
Updated on Mar 24, 2008 – SCMP

Kowloon Motor Bus is determined to keep its cool when it comes to the environment.
All of its 3,600 air-conditioned buses now have sensors that fine-tune the inside temperature in response to the atmosphere outside.

The sensors save fuel as air conditioning is used only when it is needed.

Principal engineer Shum Yuet-hung said the cabin temperature was affected by the number of passengers, the air flow at bus stops and the temperature difference between inside and outside.

“The ambient sensor fine-tunes the temperature in the bus automatically to suit different cooling requirements based on the temperature difference,” he said. “It enables the air-conditioning system to adjust its cooling according to actual needs and this helps save energy.”

Mr Shum said fuel consumption increased 1 per cent when the outside temperature increased by one degree Celsius.

“If the air conditioning is set at a certain degree and does not change, energy will be wasted in cool weather.”

KMB sets its air conditioning at 23 degrees and the humidity level at 40 per cent to 70 per cent.

The bus company said the device came into its own in spring, autumn and on rainy days, when there were big temperature differences between day and night.

The sensor aims to keep the temperature inside the bus at between 22.5 degrees and 25.5 degrees, depending on the temperature outside.

KMB introduced an enhanced air-conditioning system in 2005, which includes the ambient sensors.

The system’s “intelligent” temperature control makes adjustments every four seconds.

Why is Indoor Air Quality so Important for Schools?

George Woo RHP CIEC – Principal Consultant, Green Building & IAQ

MOST people know that when the skyline looks hazy with smog and the Hong Kong Air Pollution Index is over 100, breathing the air can be harmful. But did you know the air inside your home, office or school can make you sick?

In fact, the Environmental Protection Department in all major counties have already rated indoor air pollution among the top environmental health risks because we spend 90 percent of our time indoors. Really? Yes, just add up the time you spend at home, at work or school, on public or private transportations, meals and other entertainment. Over the past 40 years, exposure to indoor air pollutants has proven to cause major impacts in our health. Carcinogenic chemical emitted from building material, microbial cross infections such as influenza, Norovirus, SARS, Avian Flu, and other respiratory diseases such as asthma and bronchitis are affecting our family’s health daily. To make matters worse, those who are most susceptible to indoor air pollution are children, pregnant women, the elderly, and those with chronic illnesses. Children breathe in 50 percent more air per pound of body weight than adults do. US Environmental Agency (EPA) studies have found that pollutant levels indoor can be two to five times higher than outdoors. After some activities, indoor air pollution levels can be 100 times higher than outdoors.

There is good news and bad news about indoor air: the bad news is that indoor air often contains higher concentrations of hazardous pollutants than outdoor air; however, the good news is that everyone can reduce indoor air pollution.

Often, it is difficult to determine which pollutant or pollutants are the sources of a person’s ill health, or even if indoor air pollution is the problem. Many indoor air pollutants cannot be detected by our senses (e.g., smell) and the symptoms they produce can be vague and sometimes similar, making it hard to attribute them to a specific cause. Some symptoms may not show up until years later, making it even harder to discover the cause. Common symptoms of exposure to indoor air pollutants include: headaches, tiredness, dizziness, nausea, itchy nose, and scratchy throat. More serious effects are asthma and other breathing disorders and cancer.

Children and elderly may be more vulnerable to environmental exposures than adults. According to Health Canada, an estimated of 8% of adults and 12% of children are asthmatic. Most of the asthma cases among elementary school-age children could be prevented by controlling exposure to indoor allergens: biological (mould, house dust mite, etc.) and chemical (formaldehyde, nitrogen dioxide, ozone, etc.) Another major concern is influenza which can easily be cross transferred inside a school or other indoor areas.

Our children spent most of their time in school and the lack of knowledge in Indoor Air Quality (IAQ) and Indoor Environment (IE) is a critical concern. Being one of the major voluntary bodies in Hong Kong devoted in air quality, Clear the Air is launching an IAQ for Schools Program in Hong Kong from April 2008. This program includes assessment, education and planning for schools to effectively improve their indoor air quality and most important, maintain it at an acceptable level.

All schools are welcome to participate in this program. Please contact George Woo at as well as his mobile : 9802 9478 if you require more information.

Buying an Air Purifier

Published in the SCMP:

Everything you need to know about buying an air purifier
Peta Tomlinson

THERE’S NOTHING LIKE a bout of Sars to get us thinking about the air we breathe. According to the Environmental Protection Department (EPD), indoor air pollution can be responsible for irritations of the eyes, nose and throat, headaches, dizziness and fatigue, as well as asthma and lung disorders.

Sars was the trigger that sent hundreds of consumers rushing to buy air cleaners earlier this year, and two of Japan’s major manufacturers, Matsushita and Sharp, had to increase production to cope with demand. So, what do they actually do? And how do they differ from an ordinary air-conditioner?

While some air-conditioners have air-purification mechanisms – certain models by Sharp, Whirlpool and Brandt, for example – air cleaners or purifiers have additional filter functions.

Generally, air cleaners use four types of air filters: general filters, capable of removing bigger particles or dust in the air; HEPA (high-efficiency particle air) filters, effective in removing 99 per cent of dirty air particles down to 0.9-1 microns; carbon filters, containing active carbon which combats unpleasant odours; and iconic filters, which produce negative ions causing pollutants to magnetically draw together and settle on the floor or other surfaces for easier cleaning.

Units with HEPA filters also capture bacteria and are generally regarded as being best for those with nasal allergies or sensitivity to flowers, and are often the top choice for homes with young children. Beware of terms such as ‘HEPA-type’ or ‘HEPA efficiency’: this may not mean the unit has a HEPA filter.

Always ask about noise levels. Because HEPA filters work only when air is drawn through them, this can necessitate a large motor to power the filtering process. Most machines will require regular changing of filters, so be aware of maintenance costs.

Japanese brand Sharp ( and Israeli brand Amcor ( make the biggest-selling air cleaners at Fortress stores (tel: 2555 5788; Sharp’s Plasmacluster model FU-888SV, which covers 31 square metres and retails at $2,680; and Amcor’s AP 2000, which covers 29 square metres and is priced at $1,180.

Sharp has donated 26 Plasmacluster units to the Hong Kong Adventist Hospital, which have been installed in the surgical and urgent-care wards, maternity, paediatric unit and playroom, and the out-patient’s clinic. ‘Before we accepted the gift, we asked our clinical staff to look through the scientific papers and reports from a number of sources to check whether the claims made by Sharp were true,’ says director of business development Jeremy Low. ”Our clinical staff said the machines did help in cleaning up the various agents, viruses and most bacteria in the areas these machines were located.’

An on-site assessment of your home or office is available from independent air-quality testers such as Desmond D.B. Chan of Acoustics and Air Testing Laboratory (2/F, 190 Prince Edward Road West, Kowloon, tel: 2668 3423; The firm conducts a 12-point test following guidelines proposed by the EPD, which costs $6,500 for eight hours of continuous testing, or $3,500 for surrogate testing (in which four areas are tested for a half-hour period). Although the firm, being independent, does not make recommendations, householders can check results against the guidelines on the EPD website (

For more details on how to improve your indoor air quality, visit the government’s Indoor Air Quality Information Centre in Kowloon Tong (78 Tat Chee Avenue, tel: 2788 6177;

Air cleaners should be used in conjunction with effective source control and adequate ventilation.