People are clamouring to get outside. Outdoor areas have been busy since the hospitality industry got going again. Many municipalities are cutting the red tape to allow the use of extra areas to accommodate as many guests as possible despite the social distancing rules. Parking spaces have been repurposed and pavement divided up. That’s great as long as the weather holds. But the summer isn’t endless. When it rains or grows colder, indoor areas will require carefully designed hygiene concepts. To ensure their economic viability during the cooler season, business owners have been improving safety concepts for their operations since the first summer of the coronavirus. Apart from legal regulations as well as social distancing and hygiene rules, indoor air quality can also help guests and staff alike feel safer. The aim is to keep the air as free of germs and viruses as possible in order to minimise the risk of airborne transmission. And that’s not just in connection with COVID-19, but also with normal outbreaks of the common cold.
Fewer viruses and germs in indoor air
There are various ways of doing this. UV disinfection lights, for example, are designed to use UV rays to kill germs and inhibit the ability of bacteria and viruses to infect and reproduce. Ozone generators are also said to have similar effects: according to manufacturers, the devices suck in oxygen molecules that are then split by an electrical charge to create ozone, which destroys viruses and bacteria. So just set up a machine and you’re good to go? It’s not quite so simple. Since UV rays can damage skin and eyes, experts advise caution. ‘Scientific analyses of possible health-related consequences are still at an early stage,’ say sources such as Germany’s Federal Office for Radiation Protection. Nor is the use of ozone without controversy. For example, the gas may cause symptoms of irritation or bind other contaminants, experts warn.
High performance air purifiers are the current favourites among specialists and practitioners. Studies by the Institute of Fluid Mechanics and Aerodynamics at the Universität der Bundeswehr München (UniBw), for instance, have shown that indoor air cleaners can effectively reduce the risk of indirect infection by aerosols. ‘High-performance indoor air cleaners with a combination of F7 and H14 filters, such as the TAC V+, can easily keep the aerosol concentration in small and medium-sized rooms at a low level,’ says Prof. Dr Christian Kähler of the Institute of Fluid Mechanics and Aerodynamics at the UniBw. ‘These devices are therefore ideally suited to maintain a low viral load in areas such as classrooms, shops and waiting or examination rooms without having to worry about opening windows and impairing the well-being of the people in these rooms.’ Kähler also notes that this ensures a reduction of the viral load: ‘Furthermore, they also ensure a real reduction in the virus load, which often cannot be guaranteed with free ventilation provided by opening windows. Although indoor air cleaners and air treatment units minimise the indirect risk of infection, they do not protect against direct infection, which means that additional protective measures are essential.’ However, he adds, filter technologies cannot provide complete protection from infection. ‘For this reason, it is also important that we continue to keep a safe distance from other people or that we wear mouth and nose coverings. People should ideally wear particle-filtering masks or protect themselves against direct infection with transparent protective screens.’
Air filters in practice
‘We feel safer, and we’ve also had positive feedback from our guests,’ say Mariella and Peter Hartkopf of the Hotel zum Holländer in the North Rhine-Westphalia municipality of Lindlar. They opened their doors again for regular business in June. The reopening came with protection measures, a revised hygiene concept and new high-performance air purifiers. ‘Because the system removes the air in the room efficiently, the air cleaners provide a sense of safety for our employees and especially for our guests,’ report Mariella and Peter Hartkopf. The couple addressed this issue early on, coming to METRO for advice way back in October 2020. The priorities for them were the device’s functionality and performance as well as a high degree of customer satisfaction on the manufacturer’s website. After 6 weeks in operation at their business, they say: ‘The device works great.’
Germany is among the countries where air cleaners are in particularly high demand. According to current market data, the UK tops the list, with Poland and France also registering significant demand for air filtering systems. The market for these devices in Europe is forecast to grow by around 8% a year until 2026. Regulations and subsidies for technical hygiene measures vary from country to country. However, despite all the technological achievements, one thing remains paramount, as the experts continue to emphasise: each individual’s hygiene. And that means sticking with the basics: wash your hands, sanitise your hands, maintain physical distance. That way, we can look forward to the next restaurant season – not the next lockdown.