University of Helsinki Study Reveals Indoor Air Quality Concerns with UVGI Disinfection Robots

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(IN BRIEF) A study by researchers at the University of Helsinki’s Institute for Atmospheric and Earth System Research found that using ultraviolet germicidal radiation (UVGI) to disinfect indoor spaces with UV lamps can lead to increased concentrations of gases and small particles that are harmful to human health. The study, which focused on UVGI disinfection robots used in hospitals, found that concentrations did not return to their original levels until 30-40 minutes after the lamps were switched off. The researchers recommend waiting before entering a disinfected room or wearing protective gear, and suggest that the effects on air quality must be further investigated before the use of UVGI devices becomes widespread.

(PRESS RELEASE) HELSINKI, 26-Jan-2023 — /EuropaWire/ — University of Helsinki, the oldest and largest institution of academic education in Finland, announces that a new study from the University’s Institute for Atmospheric and Earth System Research (INAR) has found that using ultraviolet germicidal radiation (UVGI) to disinfect indoor spaces may have previously unexplored indirect adverse effects on people, specifically reduced indoor air quality caused by the UV radiation used.

The study, conducted by Doctoral Researcher Frans Graeffe and his team, focused on the effects of UVGI disinfection robots on indoor air quality to better understand the potential negative effects. Using a UVGI device used in hospitals, the team measured the concentration, size and chemical composition of gases and small particles formed when the UV lamps were switched on.

The results showed that every time the UV lamps were switched on, the amount of both gases and small particles increased considerably. Although both particle and gas concentrations started to decrease, they did not return to their original levels until 30 to 40 minutes after the UV lamps were switched off.

“To our knowledge, we conducted the first experimental study of the effects of UVGI devices on indoor air quality,” says Doctoral Researcher Frans Graeffe from the University of Helsinki’s Institute for Atmospheric and Earth System Research (INAR).

“We focused on the effects of UVGI disinfection robots on indoor air quality to better understand the potential adverse effects.”

Solar ultraviolet radiation enables most of the chemical reactions occurring in the atmosphere, including the formation of oxidisers such as ozone (O3) and the hydroxyl radical (OH). Bringing UV radiation indoors in the form of UVGI disinfection robots makes it possible for outdoor reactions to take place indoors. Reactions caused by radiation can form a range of gases and small particles that, when inhaled, are harmful to human health. High particle concentrations have been associated with several diseases (e.g., respiratory diseases).

“We brought a UVGI device used in hospitals to the aerosol physics laboratory at the University of Helsinki where, utilising spectrometers and other modern measuring equipment, we were able to measure the concentration, size and chemical composition of the gases and small particles formed,” Graeffe says.

“Our measurements clearly show that every time the UV lamps were switched on, as the disinfection was initiated, the amount of both gases and small particles increased considerably.”
Although both particle and gas concentrations started to decrease, for example, through ventilation, immediately after the UV lamps were switched off, the concentrations returned to their original levels only until 30 to 40 minutes later.

“After disinfecting the room, it would be better to wait for a while before entering, or to enter wearing protective gear, such as a sufficiently effective respirator,” Graeffe says.

The study’s findings suggest that the effects on air quality must be further investigated before the use of UVGI devices becomes widespread, in order to understand how different UVGI devices affect indoor air quality and how their benefits (control of viruses) compare with their adverse effects (degradation of air quality).

Frans Graeffe, Yuanyuan Luo, Yishuo Guo & Mikael Ehn: Unwanted indoor air quality effects from using ultraviolet C lamps for disinfection

Media contact:

Frans Graeffe
Doctoral Researcher
DEPARTMENT
frans.graeffe@helsinki.fi

SOURCE: University of Helsinki

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