The findings may mean that trade fairs can be held safely even during a pandemic

With the onset of the COVID-19 pandemic, events of all kinds were shut down out of safety concerns.
It was virtually unheard of for a trade show to be held over the past two years in most regions with health and safety protocols.
This was of course due to the belief that when people breathe, they emit aerosols that may include virus-infected particles, which could lead to widespread infections of a crowd in an enclosed space.
A study was held in the second half of 2021 to test the air quality during trade shows at the Messe Frankfurt exhibition grounds in Germany, which has sophisticated ventilation systems.
The study was conducted by Messe Frankfurt and a team of researchers from the Institute of Building and Indoor Climate Technology, E.ON Energy Research Centre, RWTH Aachen, and Heinz Trox Wissenschaft GmbH.
Under the direction of Professor Dirk Müller, contamination levels were measured at three trade fairs, Indoor-Air, Formnext, and Food Ingredients (Fi) Europe. These were held in Halls 3 and 12 at Messe Frankfurt.
Measurements were taken in the supply air and exhaust ducts of the ventilation systems, and there were an additional 22 censors in continuous operation during the events positioned at visitor head heights on columns, near aisles and stands, and in adjacent areas.
Aerosols are emitted through breathing the same way as CO2, so the concentration of CO2 in the air served as an indicator of contamination of indoor air.
The goal is to not exceed a CO2 level of 1,000 ppm or parts per million, as anything above 2,000 ppm is considered hygienically unacceptable.
The researchers report that in its study, all CO2 concentrations measured in the study were consistently well under 1,000 ppm, and some were just over 440ppm, which is close to outdoor air quality. They report there was a maximum level of 835 ppm on the day with the highest number of visitors.
“These new study results show that there was good air circulation in all of the halls under examination and at all three events, without any recognisable pockets of uncirculated air,” Messe Frankfurt Member of the Executive Board, Uwe Behm, said.
“The concentrations of CO2 at the individual measurement points varied only very marginally from those in the exhaust ducts, meaning that the mix of air is virtually ideal.”
Messe Frankfurt says these results are encouraging, indicating that it may well be possible to hold trade fairs safely with additional safety and hygiene measures in place even during a pandemic.

For more information and to access a link to the study, see the press section of