Staff sickness could decline thanks to new gadget


08 April 2010

Sick Building Syndrome (SBS) could finally be eradicated from offices after scientists developed a device that converts pollutants into safer substances. 

The breakthrough should reduce the number of sick days taken by employees. Some 24.6 million working days are lost annually from people in the UK taking time off because of illness.

SBS can be caused by inadequate ventilation or volatile organic compounds (VOCs), such as formaldehyde, that are emitted by chemical contaminants from carpeting, upholstery, manufactured wood products, or photocopying machines and cleaning agents. Researchers designed a photochemical device that, for the first time, works all day and night. As light is shone on the device, the energy is stored then used to oxidise pollutants, especially formaldehyde, at any time therefore improving indoor air quality.

Their work is published today (Thursday 8 April) in the Royal Society of Chemistry journal Physical Chemistry Chemical Physics.

Titanium dioxide (TiO2) photocatalysts have in the past been applied to environmental remediation and self-cleaning coatings. However, they only work under UV light, which means they stop working at night. Tetsu Tatsuma and colleagues at Tokyo University overcame this problem with their photocatalyst design having the ability to store photochemical energy.

Tatsuma's photocatalyst has two layers: a titanium dioxide underlayer and a nickel hydroxide Ni(OH)2 overlayer. As the light is shone onto the device, its energy can be captured by the underlayer and stored in the overlayer. Harmful VOCs will be trapped on the film during the night. In the morning light, the stored energy is used to oxidise the VOCs into less harmful compounds such as carbon dioxide and water.

Tatsuma said: "We hope to apply it to private houses and offices and factories as coatings, for instance, in curtains, window blinds and ceilings." Indoor air quality will be improved and the risk of SBS reduced by removing formaldehyde from the work environment.

Mark Clayton, a Public Health Service Officer from the US EPA Indoor Environments Division, said: "This system could represent a significant advance in potentially reducing airborne concentrations of chemical compounds commonly found in an environment where most people spend 90 percent of their time. Employment of such a photocatalyst may have the potential to make a substantial contribution to ongoing efforts to improve air cleaning devices."

The NHS website calls SBS a "poorly understood phenomenon" where workers in particular office environments complain that they are experiencing a range of symptoms such as headaches, fatigue, skin rash and itchy skin among others. The symptoms usually resolve once the affected person has left the building.

Women are more likely than men to be affected by SBS. Anyone working in a large open plan office with automated heating, ventilation and air-conditioned systems are prone to SBS. Researchers have been trying to identify a definitive cause of SBS since the 1970s but have as yet been unable to do so. One theory is that SBS is, at least in part, due to changes in building and ventilation design triggered by the energy crisis in the 1970s.

A 1984 World Health Organisation report on SBS suggested up to 30 per cent of new and remodelled buildings worldwide may be linked to symptoms of SBS.

References

Oxidation of methanol and formaldehyde to CO2 by a photocatalyst with an energy storage ability
Fei Yang, Yukina Takahashi, Nobuyuki Sakai and Tetsu Tatsuma, Phys. Chem. Chem. Phys., 2010
DOI: 10.1039/b925146d

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