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Workers in certified green buildings perform 26 per cent better on cognitive function tests than workers in non-certified ones, new medical research from the US has found.

The Buildingomics study examined cognitive function in 109 office workers across 10 high-performing buildings in Washington, Boston, Los Angeles, Denver and San Jose.

All of the buildings exceed the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standard for ventilation, indoor air quality and low volatile organic compound concentrations, however only six of the 10 had formal LEED certification.

The workers were tested for a week, performing two sets of cognitive function tests. In addition their sleep quality was tracked, and they completed surveys about their health in relation to 19 established sick building syndrome symptoms. The participants were also surveyed about their satisfaction with their office environment, including noise levels, lighting and thermal comfort.

Researchers identified a number of contributing factors leading to higher cognitive performance for workers in certified spaces. They include lower levels of humidity, putting more people within the thermal comfort zone as defined by ASHRAE, and better sleep due to the better lighting in the LEED certified buildings.

Participants also reported 30 per cent less “sick building symptoms” in the certified buildings.

The study, carried out by researchers from the Harvard TH Chan School of Public Health’s Centre for Health and the Global Environment and the SUNY Upstate Medical University, is the second part of larger research project, the Impact of Green Buildings on Cognitive Function Studies, known as the COGfx studies.

The first study, carried out in conjunction with the Syracuse University Center of Excellence’s Total Indoor Environmental Quality Laboratory, compared the cognitive performance of workers in simulated green building environments with those in conventional buildings. It found participants performed twice as well on cognitive function tests in the simulated green office.

The team is now working to further refine the findings on what the key influences are on the productivity and health of workers, with the aim of providing information that can be used by building practitioners to improve the performance of buildings.

The researchers have said they proposed the term “buildingomics” to “capture the complexity of the research of health in buildings”.

“Buildingomics is the totality of factors in the building-related environment that influence human health, wellbeing and productivity of people who work in those buildings.”