We have been discussing at our blog the solid air interface as a dynamic process vs. a static process. Once particles – bacteria, virus, pollen, dirt, chemicals – that are on a surface the can be aerosolized with movement of people equipment or air. In part because of this, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommends sub-micron filtration for hospitals and nursing homes. Below are links to some pieces that illustrate that need.
- In a segment of a National Academy of Sciences, Engineering and Medicine meeting titled “Microbiomes of the Built Environment,” Donald Milton presents on the transfer of infectious disease via the air and some models to use in predicting the likelihood of these transfers in this YouTube piece: Donald Milton – Models: How to think about infections in the air? In his informative talk, Milton outlines how normal breathing, not just coughing and sneezing, contributes to the spread of respiratory viruses. He also notes that movements indoors cause several times the bioaerosol particles to be emitted, with the majority of those coming from the floor. Milton is Professor of Environmental Health, Applied Environmental Health (MIAEH) and Affiliate in Cell Biology and Molecular Genetics; Professor, Internal Medicine, University of Maryland School of Medicine.
- At the same gathering, Perspectives on Microbial Interactions in Built Environments presented by Brent Stephens discusses how the indoor environment impact indoor air quality (IAQ). The bulk of the particles in coughs and sneezes are sub-micron sized, which supports ASHRAE’s recommendation for sub-micron filtration in hospitals and nursing homes. Stephens is an expert in the fate and transport of indoor pollutants, building energy and environmental measurements, HVAC filtration, human exposures to airborne pollutants, energy efficient buildings, energy and environmental policy.