Coronavirus found in aerosols

Good indoor air quality reduces the risk of Sars-CoV-2 infections.

It has thus far been assumed that the Coronavirus is transmitted via the air, especially in the form of droplets. US researchers have now presented evidence that aerosols emitted by those infected with the Coronavirus may also contain intact virus particles. Droplets and aerosols are released through breathing, speaking and coughing. Compared to the droplets, these aerosols are clearly smaller and remain in the air for much longer (from hours to days). This means that they can be evenly distributed in rooms and lead to infections, despite the safety distance of 1.5 meters being adhered to. It is currently not yet clear how many infections are caused by aerosols.

The general rule is that the risk of transmission in poorly ventilated indoor spaces is significantly higher than outside, where the particles volatilize more rapidly. In closed rooms housing many people, such as classrooms or open-plan offices, good indoor air quality is thus of increased importance. The following measures may result in the minimization of the infection risk at operating sites:

  • The most important way to prevent infections is by adhering to the hygiene measures communicated by the BAG (Federal Office of Public Health) (BAG).
  • Regular ventilation and cross-ventilation reduce the concentration of aerosols in the air and thus the risk of infection. The German Federal Environmental Agency (UBA) also recommends that offices should be thoroughly ventilated after individuals have coughed or sneezed (Umweltbundesamt).
  • A well-maintained ventilation system ensures a continuous supply of fresh air and also reduces the risk of infection. Air-conditioning systems should be switched off during the current pandemic, with ventilation in use continuously.
  • CO2 measurements are a useful indicator for the general evaluation of indoor air quality and can indicate when ventilation is required. Under normal conditions, a CO2 concentration of less than 1 000 ppm (0.1 % by volume) indicate hygienically adequate air exchange. In the current situation, ventilation of indoor spaces is already recommended at concentrations superior to 800 ppm.
  • In individual cases, portable air purifiers can be used as additional measures to prevent the possible spreading of infectious particles.

Detailed recommendations about reducing the Sars-CoV-2 risk may be found at the following website of the Swiss Association for Air and Water Hygiene (SVLW): SVLW

The Indoor air experts at Ecosens AG possess the knowledge and necessary equipment to determine the indoor air quality at your site. They also offer consulting services for improving the indoor air quality and for optimal use of ventilation options, thus contributing to a reduction of the infection risk.

Your contact person:

Pascal Diefenbacher

Departmental Manager for Indoor Air Quality