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Photo: Sofia Stridsman
Luleå University of Technology professors Mikael Sjödahl and Staffan Lundström. Photo: Sofia Stridsman View original picture , opens in new tab/window

How effective are face masks?

Published: 7 April 2020

How do particles spread when a person coughs with or without a face mask? A group of researchers, including from Luleå University of Technology, wants to increase knowledge about this.

The coronavirus outbreak has raised the question of how well face masks prevents the spread of disease. In some countries, people have to cover their faces before going to grocery stores and pharmacies, while in other countries it is mainly healthcare workers that use face masks.

By compiling what is known from previous studies and doing new data calculations and simulations, a network of researchers from Luleå University of Technology, Chalmers, KTH, Lund Faculty of Engineering and Aalto University in Finland wants to improve knowledge about the effectiveness of face masks.
– We can do advanced experiments thanks to the equipment we already have here at Luleå University of Technology. We can measure flow fields in volumes and see how particles are dispersed if someone coughs with a face mask and without a face mask, explains Staffan Lundström, professor in fluid mechanics at Luleå University of Technology.

How droplets are spread

By using the Schlieren photography technique, it is possible to see on film how droplets are spread when a person coughs.
– It will be very interesting to see how large particles differ from smaller particles in terms of dispersion, depending on whether a face mask is used, says Mikael Sjödahl, professor in experimental mechanics at Luleå University of Technology.

The researchers will soon make the first measurements. They hope to be able to contribute quickly to spreading knowledge about the effectiveness of face masks/medical masks.
– We have previously collaborated on flows of particles, and have quickly formed a network to now be able to focus on the spread of infection and exposure linked to the coronavirus, says Staffan Lundström.

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