SCMP Friday, March 9, 2001
Something in the air
Sick building syndrome. It's an evocative term, conjuring images of some decrepit edifice, coughing up dust, soot and microbes from the greasy depths of ancient, groaning lungs. And then, through the chainsmoker-black alveoli of its air-conditioning ducts, showering inhabitants with its expectorations.
But appearances can be deceiving. Even the glossiest, glassiest new towers may be guilty of circulating the sort of potent chemical and bacterial soup that sends workers home wheezing. And experts estimate Hong Kong companies are losing hundreds of millions of dollars a year as a result of productivity lost through illness caused by poor indoor air quality.
Your office might seem like a hermetically sealed sanctuary from the steamy smog outside. It's not. Most air-cooling systems simply suck air in from the street through less-than-effective filters, cool it down and pump it round and round (sometimes through grimy, rat and cockroach-infested ducts). Factor in the volatile solvents and formaldehydes used in furniture and carpets, dangerous compounds given off by new computers, mould, mildew and the pheremonal fug from humans and you get a cocktail often far more dangerous than anything you could breathe outside.
What if the answer was as simple as plugging in a couple of cabinets about the size of your average dehumidifier? A Hong Kong company has patented what it claims is a revolutionary "molecular sieve" that removes or greatly reduces many harmful indoor pollutants and could literally prove a breath of fresh air for the SAR's office-dwellers.
Oxyvital, best known for its yuppie and tai-tai-filled "oxygen bar" in Central where customers can spend 20 minutes imbibing near-pure oxygen, is the company behind an unassuming-looking box named the P15000 and its smaller cousin, the P6000. Founder and managing director, Ilsa Massenbauer-Strafe, says a battery of tests both by her company and by independent scientists, have shown use of the device leads to a dramatic drop in airborne pollutants including carbon dioxide, carbon monoxide, nitrogen dioxide, formaldehyde and the lung-clogging little nasties known as respirable suspended particulates.
Massenbauer-Strafe says the molecular sieve concept, which breaks compounds back into their constituent elements through a process of absorption and catalysation, was developed by scientists from the company's German partner, Medicap.
"Actually, we weren't thinking specifically about indoor air quality at that point," she says. "The technology was developed as an alternative to oxygen tanks, which can be dangerous because they're highly flammable, to use in the oxygen bars." She says what happened next was, like many scientific breakthroughs, pure serendipity. "I noticed that after the machines had been running in the bar, the general air quality in our offices seemed better. After years of coughing and sneezing, I wasn't getting sick anymore."
Tests were commissioned and Massenbauer-Strafe says she was stunned by the results. All the "bad stuff", as she puts it, had dropped to much lower, and in some cases almost undetectable, levels. More comprehensive tests were then arranged, at offices in Tsim Sha Tsui and Mongkok. These tests were conducted by Oxyvital scientists and also by the independent contractors Lam Geotechnics.
The Mongkok tests were carried out on the 3,500 sq ft third floor of a government building, where the P15000 was set up next to the air-conditioner's intake unit. The ventilation system drew in air from the street, with no recirculation or forced exhaust. Between 11 and 15 people worked in the office, the exact location of which Oxyvital and the government department involved asked be kept confidential.
On January 11 last year, the machine was switched on. After three days of continuous operation, the level of carbon dioxide had dropped from about 950 ppm (parts per million), which is more than the World Health Organisation (WHO) recommended limit of 800 ppm, to about 650 ppm. When the unit was turned off on February 3 the level rose to more than 1,000 ppm within days. When it was turned on again, it fell to just more than 400 ppm by early March. The study notes that the falls in C02 were recorded "despite the total air movement of the [P15000] generator [representing] only a small fraction" of the 80 cubic metres sucked in every minute from the street.
Deadly carbon monoxide dropped from 5 ppm (5,700 micrograms/cubic metre, about half the maximum WHO recommended level) to an almost undetectable level by February 28. When the machine was turned off, the level rose back to 6 ppm after two weeks.
The Tsim Sha Tsui tests were carried out in a 200 sq ft conference room on the 21st floor of a well-known office tower. "We had a lot of people crammed into the room and they were smoking, there were cigarettes burning in ashtrays, to get all the [dangerous gas] levels up pretty high," says an Oxyvital spokesman. "Then we took everyone out, turned on the P6000 and shut the door."
In the first 24 hours, carbon dioxide dropped from 1,750 ppm to 1,550 ppm. After two weeks it was down below 700 ppm. Carbon monoxide levels after 24 hours had fallen from 5 ppm to undetectable levels. Respirable suspended particulates went from 4,200 micrograms/cubic metre (more than 20 times the WHO recommended maximum of 180) to 100 micrograms/cubic metre. Formaldehyde dipped from 200 micrograms/cubic metre (double the WHO suggested limit) to 30 micrograms/cubic metre, while nitrogen dioxide dropped from 12 ppb (parts per billion), already about half the WHO maximum, to 6 ppb.
"The tests confirmed that the unit gets rid of suspended particulates, carbon monoxide, nitrogen dioxide and formaldehydes pretty fast," the spokesman says. "Carbon dioxide takes longer to come down because it's a double-bonded molecule and harder to break up. Plus it's continually being replenished by people."
The Government has declined to comment on the tests, with an Environmental Protection Department spokesman saying: "It's a commercial venture, so it's not appropriate for us to say anything."
The EPD has pinned its hopes for better indoor air on a voluntary scheme, planned to start later this year, where participating companies would be given an indoor air rating after being tested.
Hong Kong Productivity Council environmental consultant Raymond Fong is also non-committal about the Oxyvital machine. "We don't have any plans to test it ourselves," he says.
There is likely to be plenty of interest in the private sector, however. According to Fong, hundreds of SAR companies have asked the council to test their indoor air in the past year or two. "Most of the tests show room for improvement," he says.
"I suppose they want to find out now, so they can make improvements when the rating scheme comes in."
The academic world has also pricked up its ears. Dr Ming Ho, curriculum programme manager of the Polytechnic University's Building Services Department, says he's keen to find out more about the P15000. "We'd certainly be happy to help the company if it wants to do wider testing - on a confidential basis of course," he says. "Sick building syndrome is, according to our research, a common problem in Hong Kong and any effective new technology is to be welcomed."
Two weeks ago, Oxyvital flew in German sick building guru Dr Richard Straube to help talk up its product. The gruff, moustachioed Straube, chief resident of the Nephrology Department at Luedenscheid District Hospital and now a consultant to Oxyvital, says he's been interested in the effects of indoor air pollution on humans since 1983.
"This molecular sieve concept has enormous potential," he says. "One gram of this material has an internal surface area of about eight billion square metres. And there is about five kilograms of it in each machine."
The company is not keen to publicise the actual material used in the sieve, but the South China Morning Post understands it is based on a naturally occuring, powdery substance called alumo-silicate.
Straube has strong opinions on sick buildings. He says human by-products can be just as disturbing to workers as pollution sucked in from outside. "I call it office smog," he says. "Often when you get to the office there's a particular mood and you can't explain why. It may be a good mood or a bad mood.
"There is a fog of about 2,000 chemical substances that each human being gives off. Do you know . . ." he pauses for effect, "every person sheds 1.5 litres of dust every day from their skin?
"When an office is crowded or poorly ventilated, we see what we call 'mobbing' behaviour start to take over. This is when these substances act on the limbic system of our brain, which controls our moods, our emotions. You get high concentrations of pheromones, cortisols, testosterone, oestrogen in the air and you have a sensory structure in your nose which can detect them. It can make people aggressive, irritable or territorial."
Straube says he plans to publish in a series of articles in British medical journal The Lancet later this year on "mobbing" and the P15000's efficacy in ridding the air of these compounds.
"We are finishing the research now," he says.
Clean, fresh air constitutes 78 per cent nitrogen, 21 per cent oxygen and one per cent other gases. "In an unhealthy indoor environment this delicate balance is disturbed by airborne pollutants leading to sometimes dangerously low concentrations of oxygen," Straube says. "Many air-conditioning systems also enhance bacterial agents. It all combines to mean illness and immune system breakdown."
In the US, the Environmental Protection Agency estimates US$1.6 billion (HK$12.5 billion) is lost through sick-building-related illnesses. No official Hong Kong figures are available, but Straube believes, based on extrapolation, that HK$460 million is a conservative figure.
He says carbon monoxide intoxication is a particular risk in Hong Kong, with so many buildings drawing air from the narrow canyons between high-rise clusters. Prolonged exposure can lead to cardiovascular problems and lung cancer.
Massenbauer-Strafe says she has conducted dozens of indoor air tests in Hong Kong offices and seen results from dozens more. She is yet to see a single office which meets all of the WHO's indoor air quality guidelines. "Our machine represents good value for money," she says. "The P15000 can cover about 3,000 sq ft and costs $55,000. The P6000 is $28,000 and covers about 700 sq ft, so it is suitable for most Hong Kong flats. It's like a dehumidifier. You just plug it in and turn it on. We also have a bigger unit for large commercial premises." The machines are also equipped with dust and bacterial filters, which catch bigger particles before they reach the molecular sieve. Oxyvital will provide the annual service the machines require.
Massenbauer-Strafe also claims the machines can help cut energy bills. "Now, you have to suck in air that's 30 degrees Celsius and cool it down to 20. The dirty air is blown into offices and recirculated two or three times per hour. We have found that because the air is much cleaner, you don't have to make it so cold. Even if you only cool it down to 24 degrees, people feel better because their bodies are telling them they can breathe more easily.
"I believe these machines can pay for themselves very quickly. Indoor air pollution affects everybody. It's not just workers. The boss of Hutchison Whampoa, the boss of Sun Hung Kai - they are breathing the same air too."