Ventilation system contamination may cause sick building syndrome
Sick building syndrome may be successfully treated by installing ultraviolet lights in ventilation systems, researchers have said.
Sick building syndrome is a term used to describe a range of symptoms suffered by office workers, such as headaches, fatigue, difficulties in concentrating and respiratory problems.
It has been estimated that these symptoms occur in 20% to 30% of office workers.
Some researchers believe that high levels of bacteria and fungi in ventilation systems could be to blame.
These micro-organisms have been detected in high concentrations on cooling coils, filters, drip pans, humidification systems and in the ductwork of the supply air.
A report in the journal Occupational Environmental Medicine says that the health of office workers improved after high intensity ultraviolet lights were installed in the ventilation systems serving three floors of an office building in Montreal, Canada.
In total, 113 management employees worked on these floors, of which over 80% were non-smokers.
Switched on and off
The lights were switched on and off for a total of four alternating blocks of three weeks each.
The levels of airborne bacterial and fungal organisms remained the same throughout the study, but were virtually eliminated from the surfaces of the ventilation system within three weeks.
The employees reported fewer symptoms when the ultraviolet lights were operating and took less sick leave. They were aware that the lights had been installed, but could not tell when they had been switched on or off.
Employees are not directly exposed to the UV rays, so the system is safe, and is relatively cheap, say the authors.
They suggest these lights could be installed in the air conditioning, ventilation, and central heating systems of most existing modern office buildings and high rise towers, and would kill a wide range of microbes.
This might alleviate symptoms often referred to as sick building syndrome, they conclude.
The ability of ultraviolet lighting systems to kill microbes has been known for many decades. It is used in hospitals, food processing plants and pharmaceutical manufacturring.
Until now it has not been used in ventilation systems because of technical limitations.
However, newly developed high intensity lamps have overcome these limitations.
ITGS – Areas of Impact
Home and Leisure
Homes and Home Networks: lighting
Lighting the key to energy saving
A global switch to efficient lighting systems would trim the world's electricity bill by nearly one-tenth.
That is the conclusion of a study from the International Energy Agency (IEA), which it says is the first global survey of lighting uses and costs.
The carbon dioxide emissions saved by such a switch would, it concludes, dwarf cuts so far achieved by adopting wind and solar power.
Better building regulations would boost uptake of efficient lighting, it says.
"Lighting is a major source of electricity consumption," said Paul Waide, a senior policy analyst with the IEA and one of the report's authors.
"Nineteen percent of global electricity generation is taken for lighting - that's more than is produced by hydro or nuclear stations, and about the same that's produced from natural gas," he told the BBC News website.
The carbon dioxide produced by generating all of this electricity amounts to 70% of global emissions from passenger vehicles, and is three times more than emissions from aviation, the IEA says.
Not many inventions last for more than 100 years without major modifications.
The incandescent light bulb, developed a century and a quarter ago by luminaries including Sir Joseph Swan and Thomas Edison, is one, and still produces almost half of the light used in homes around the world.
But incandescent bulbs are very inefficient, converting only about 5% of the energy they receive into light.
The biggest consumer is the fluorescent tube. Commercial and public sector buildings account for 43% of the electricity used for lighting; and here, fluorescents dominate.
The report notes that the efficiency of tubes can vary widely, between about 15% and 60%.
Regulations on their use vary widely, too. Health and safety concerns dictate what light levels should be achieved in various buildings, but the IEA found the levels prescribed by regulatory authorities vary by a factor of 20 from one country to another.
EIGHT FOR THE SCRAPHEAP
Low-efficiency fluorescent tubes
High-loss "ballasts" for fluorescent tubes
High-loss halogen transformers
Mercury discharge lamps (often used in street lighting)
Low-efficiency vehicle lighting
Fuel-based lighting in developing countries
The IEA reserves particular ire for that favourite of the western middle-class lounge, the halogen uplighter.
"This... is the least efficient of all commonly used electric lighting systems," it says. "They add a large amount of heat into the living space as a by-product... this heat might require additional air-conditioning energy for its removal."
It is concerned too that a significant proportion of the world's population has no access to electric lighting at all. Instead, they rely on burning fuel, which is expensive, inefficient, produces poor light quality and contributes to respiratory disease.
Energy-efficient lighting can seem such an obviously good idea that it is hard to comprehend why it is not used everywhere.
"There is no single panacea," said Dr Waide. "What we suggest is setting up a comprehensive set of policies.
"There is a strong case for introducing lighting measures into building codes. Currently codes have a lot of energy measures in them, but with few exceptions there aren't specific provisions for lighting."
Such codes could, for example, mandate the use of highly efficient fluorescent tubes and ballasts, the devices which regulate input voltages for the lamps; at worst these can consume 40% of the energy going into the system.
China, the IEA reports, has recently developed such codes. If they are implemented in all new build, this would "...offset the need for a new Three Gorges Dam project every eight years".
For the individual, the most obvious switch to make is from incandescent bulbs to compact fluorescent systems (CFLs), marketed in many countries as "energy-saving bulbs".
The IEA calculated the total costs to the consumer associated with buying and then using the two types, and found a significant difference.
"The overall cost of 10,000 hours of light provision from incandescents is 85 euros," said Paul Waide, "but for CFLs it's 25 euros, because they use so much less energy, and because you might have to buy only one CFL for every 10 incandescents."
He acknowledged there were concerns about the quality of light coming from some CFLs, and that some consumers reported lower lifetimes than manufacturers claimed; the key here, he said, was better regulation of the product sector by governments.
"There is also a lot that governments could do to reduce the price differential between CFLs and incandescents; it's extremely efficient from a societal perspective."
The future may see even more efficient systems. LEDs hold out the most promise; currently four times as efficient as incandescents, manufacturers are aiming for 80% efficiency by the end of the decade, which would represent a 16-fold improvement on the traditional bulb.
But, the IEA concludes, there is no need to wait for LEDs. Policy measures and individual action to bring the switch would slash 38% from the global electricity bill for lighting by 2030.
Electric light is one of the greatest advances of the modern world, but, with the rise of light pollution, it has proved to be something of a mixed blessing.
The twinkles of the stars are fewer these days - drowned in the glare of Earthly light sources. Light pollution has become a problem, and not just for astronomers - although they are among the most frustrated with it.
"I think it's terribly important to see the stars," space expert Heather Couper told BBC World Service's One Planet programme.
"You get the impression that what light pollution is doing is knocking out the landscape of what's above us.
"Imagine if you lived on Venus, which is continually veiled with clouds - you'd never see the stars, and you'd be 'landlocked'; you could only look at your own landscape."
Because LEDs are so small, we're able to put them into very efficient optical systems - waste light is significantly reduced
Mike Simpson, Philips Lighting
Much of the light generated on Earth is wasted, spilling out into space.
Incandescent lightbulbs, the type which have a filament inside, account for around half of the lightbulbs in homes around the world. But only about 5% of the energy they use is actually turned into light. The other 95% is wasted.
Paul Wade of the International Energy Agency (IEA) says that this is a dismal state of affairs.
"We estimate that around 19% of all electricity is being used for lighting in one form or another," he said.
"To put that in context, that's equivalent to using all the power produced by nuclear or hydro power, plus another 15% on top of that, just for lighting applications."
The IEA projects that the energy need for lighting will grow by around 80% between now and 2030 unless efficiency efforts are made.
However, Mr Wade added that the "good news" is that there are enormous inefficiencies in normal lighting practices, "which means an awful lot more can be done to get the same service for much less energy".
Indeed, it is believed that a major advance in light technology is not far away. The latest advances have been light-emitting diodes - LEDs - and are developing at a very fast rate.
Because the individual LEDs are so small, they can be put into efficient optical systems, directing the light.
"With the conventional lighting equipment, a lot of the light that you want to go onto a building actually shoots past it and goes off into the night sky," said Mike Simpson, the technical and design director of the lighting division of electronics giant Philips.
"Because the LEDs are so small, we're able to put them into very efficient optical systems - which means that the waste light that we have doesn't completely disappear, but is significantly reduced."
Mr Simpson said that in total, at least 50% of the light that is currently wasted can be captured.
Over the past five years, Philips has invested around 400m euros in "green light technology".
It now estimates that replacing all the standard lightbulbs in Europe with new energy-efficient ones could cut carbon emissions by 28million tonnes a year - the equivalent of 50million barrels of oil.
LEDs are becoming ever more commonplace
But even bigger savings could also be made by using light in a more selective and controlled way.
According to Paul Wade, that includes learning to make better use of daylight, and learning when to switch the light off.
"There are many options to use daylight more efficiently - including technologies which would automatically dim artificial lighting systems in response to rising daylight levels," he said.
"There are also occupancy sensors, which can tell when people have left the space and turn off the light."
Meanwhile, Philips is promoting an automated lighting control system, which is on when people are present but turns itself off when they leave.
"We estimate that by using very basic lighting controls for an office environment, you could probably save 50% of the energy," said Mr Simpson.
"We've all been past large office blocks in the city and seen the lights burning all through the night. It's completely unnecessary."
ITGS – Areas of Impact
Home and Leisure
Homes and Home Networks: Security
Bus CCTV could predict assaults
CCTV security systems could soon spot an assault on a bus before it happens, according to a major research project.
The system, part of which has already been tested in laboratory conditions, looks for suspicious behaviour associated with crime.
It would be able to send live CCTV pictures to operation rooms, from where controllers would be able to intervene.
The Queens University Belfast team say the software could make a significant impact on crime on transport.
Although much of the work is currently at the theoretical stage, the team from the university's newly-founded Centre for Secure Information Technologies predict that within five years their software will be able to profile people as they board a bus.
If a security analyst can directly communicate with the assailant, to tell them they are being watched, it will have a marked effect on the offender
The system would then compare who it thinks these people are, and what they are doing, with more general data on the bus's location, time of day and historic crime rates.
Once it has sifted this data, it could be able to conclude whether someone is about to commit an assault and send live pictures to controllers.
Dr Paul Miller, head of the research project, said there were millions of CCTV cameras in the UK doing very little to fight crime.
POSSIBLE SIGNS OF CRIME DETECTABLE BY SMART CCTV
Closing in on a passenger
Groups of young men
Shouting at a driver
People loitering on stairwells
"Their impact on anti-social behaviour and criminal behaviour is negligible - assaults on buses are a major problem and very little CCTV material is analysed in real-time," he said.
Dr Miller said the 15-strong team were still developing initial databases to identify an individual's gender and body shape.
However, the team say the system goes further by then looking for recognised signs of an imminent criminal offence.
These signs include someone moving seats shortly before an assault, groups closing in on a passenger sitting alone and people loitering on a double-decker's stairwell, or close to the driver's cab.
The system would only alert a controller if the sum of all of these "atomic events" added up to the profile of a possible crime.
"The system won't be able to say, 'this is an incident' - but it will be able to push that video stream to the top of the queue for security analysts [in a control room] to make a decision," said Dr Miller.
"Ultimately, most of the events will be benign, with nothing going on. That's why you still need the human element."
Dr Miller said that laboratory tests on gender recognition, based on a database of 4,000 faces, had proved successful and the project would move into testing systems on buses over the next year.
He conceded that buses were a "pretty challenging environment" for the software - but the benefits could be enormous.
"Research shows crimes happen when there is an opportunity and no chance of payback," he said.
"If a security analyst can directly communicate with the assailant, to tell them they are being watched, it will have a marked effect on the offender. Just one example of this actually happening can have a deterrent effect on the crime rate in an area."
The CCTV project is among research being conducted at the Centre for Secure Information Technology, which has launched this week. CSIT says it aims to be a "leading edge" centre in taking theoretical university work on combating cyber crime and improving security and turning it into practical tools to help police and other security services.
ITGS – Areas of Impact
Home and Leisure
Homes and Home Networks: Security
How to outwit a burglar
New research suggests that alarms and home security systems don't deter burglars, so what does?
Britons spent an astonishing £522m last year on measures to protect themselves against burglars, according to the Institute for Public Policy Research.
But new research suggests it is a waste of money as burglars are not deterred by alarms, home security systems or dogs. They simply choose homes that offer easy access and escape routes and appear "profitable'' targets.
So if the latest high-tech security systems won't stop a burglar, what will? It is a question that more and more people are asking. The most recent British Crime Survey, released in February, showed the burglaries in England and Wales fell by 7% last year but still topped 75,000.
Almost half of 50 persistent burglars interviewed for the study by researchers from Portsmouth University believed home security had improved over the past 10 years, but all of them felt security features were "rarely enough to deter them''.
Burglars have a mental map when they do a job, which comes automatically. What they rely on is the fact that most householders leave valuables in predictable places, meaning most homes can be searched in exactly the same way.
Their search pattern usually involves heading for the main bedroom, as the most likely location for hidden valuables, then moving to other bedrooms and living rooms.
WHO, WHAT, WHY?
A regular feature in the BBC News Magazine - aiming to answer some of the questions behind the headlines
This is also true of people who have been broken into, which is why multiple victimisation is such a big problem when it comes to break-ins. One in four burglary victims have had their homes targeted again, according to Victim Support.
People often replace items and put them in exactly the same place, so burglars not only know where to look but are also familiar with the layout of the property.
Researchers say changing the usual lay out of a house is one of the best ways to put off a burglar.
"You need to throw them off the scent and keep them guessing," says Dr Claire Nee, director of the International Centre for Research in Forensic Psychology at Portsmouth University, who carried out the research.
"They have a mental map which comes automatically to them and they rarely deviate from this unless they think there will be a big payoff. Changing the layout of a house to something a bit more unusual - like some people have the lounge upstairs these days - will deter them."
Another tip is to leave valuables in a child's bedroom. The study found the bedrooms of young children are rarely searched as burglars don't expect to find anything of value in them.
"I have been researching burglary since the late 1980s and the decision making process thieves use has not changed," says Dr Nee.
"How they carry out a burglary remains the same because homeowners keep making the same mistakes. It's gob smacking."