Photo: Mikal Schlosser

Human impact on indoor climate is being mapped

Monday 20 May 19


Gabriel Bekö
Associate Professor
DTU Sustain
+45 45 25 40 18


Pawel Wargocki
Associate Professor
DTU Sustain
+45 45 25 40 11

Indoor climate

We spend about 90 per cent of our time indoors, and indoor climate is therefore of great importance to our health and well-being.

The indoor environment constitutes an important source of chemical pollutants to which the residents are exposed. Humans are one of many sources of indoor pollution. In recent decades, the construction industry has had much focus on using low-polluting materials. However—with increasingly airtight buildings—substances emitted by humans are becoming a dominant primary indoor pollutant.

Emissions from human respiration and skin—and their chemical transformations—have not been mapped, and the importance of these processes is thus not known. Today, carbon dioxide (CO2) is used as a marker for biowaste substances from humans which is used to control room ventilation. But there are also many other human pollutants that affect the indoor climate and that can form part of other chemical compounds.
Advanced climate chamber measurements provide new knowledge about human emissions and impact on indoor climate in buildings.

Human impact on the indoor climate is being mapped for the first time in a large-scale test at DTU.

Over five weeks, researchers will examine human impact on the indoor climate by measuring the substances and chemical emissions that humans emit. The test will be performed with advanced instruments that have previously been used for measurements of the atmospheric climate and registration of climate change.

“We’ve not previously been able to measure with such great precision the chemical processes that occur in the indoor climate. But new advanced equipment and new analysis methods enable us to map how emissions from humans affect the indoor climate. This is knowledge which is becoming increasingly important because we spend 90 per cent of our time in buildings, and because our dwellings are today so well insulated and airtight,” says Gabriel Bekö, Associate Professor at DTU Civil Engineering.

The project ‘Indoor chemical human emissions and reactivity’ (ICHEAR) will be carried out in climate chambers at DTU Civil Engineering. The project is a unique collaboration between chemists and civil engineers, and involves sophisticated analytical systems from the German Max Planck Institute for Chemistry—MPI-C—and the Swedish Environmental Research Institute, IVL.

Associate Professor Pawel Wargocki at DTU Civil Engineering—who is one of the four primary researchers behind the test—points out that there will always be human emissions in the indoor climate even though pollution from other sources is removed.

“In recent years, there’s been focus on how sources such as building materials and furniture affect the indoor climate. This test goes back to the starting point and looks at people as one of the fundamental sources of pollution affecting the indoor climate,” says Pawel Wargocki.

Every morning, four persons will arrive at DTU and spend their day working in the climate chamber. Before the participants show up, they have been given dietary instructions and been informed that they are only allowed to take a bath between 9 p.m. and midnight, and that they must use a specially selected soap and shampoo. In addition, the participants will be issued with identical clothes—either T-shirt and shorts or long shirt and trousers.

In the test, the researchers will continuously measure a number of organic and non-organic substances and particles down to one nanometre size. Samples will be taken from the test subjects’ skin, on surfaces in the climate chamber and on the clothes that the test subjects are wearing. Using a reactor developed at the Max Planck Institute for Chemistry, the researchers will also look for other pollutions which cannot be picked up with conventional chemical analyses.

The measurements will be done under conditions with low or high temperature, respectively, changes in air humidity, with and without the presence of the gas ozone. The researchers will separate pollutions emitted either by human skin or exhalation air and examine differences in emissions from children, young persons, and adults.

Gabriel Bekö and Pawel Wargocki expect that the test results may—among other things—contribute to a new understanding of the importance of ventilation and to the development of new ventilation control sensors. They will also contribute to an understanding of fundamental chemical and atmospheric indoor climate transformations.

The ICHEAR project has been funded by a grant of USD 410,000 from the American Alfred P. Sloan Foundation, and the test results are expected to be published at the end of 2019.

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