Read this sentence aloud: With every passing word, an expanding blast of spittle spews from your mouth the more emphatic the speech, the greater the spray.
This mouth-made mist is the subject of a great debate about how the coronavirus hitches a ride from person to person. Virus-riddled globs can be inhaled, or even land in the eyes, potentially sparking infections in others. But for respiratory diseases like coronavirus, it’s long been thought these droplets are so large they will fall rapidly to the ground, inspiring public health recommendations such as cleaning surfaces and keeping six feet of social distance.
Other scientists, however, have become increasingly concerned that the novel coronavirus spreads through a more insidious route—as an airborne pathogen. Every sneeze, cough, spoken word, or even exhaled breath expels droplets in a continuum of sizes.
In order to educate you about airborne microbes in different environments, I will let you know a little bit about when, where and how you can find these little, microscopic buggers and what kind of effect they'll have on you or your family. Everyone has their own natural microorganisms that live on, in and around their own bodies. These bacteria are known as natural flora and our own bodies (specifically the immune system) recognize that they are good for us. We, as humans, would not survive without such creatures. However, this website gives information regarding pathogenic microorganisms in general. That is, things that you can't see causing physical harm.
Chances are that you most likely got sick from an airborne pathogen. In other words, the germ or irritant floated from one person to another. This happens a lot in the winter, for instance, because the air is dry, making our sinuses more prone to infection. Also people tend to stay inside more during the winter season, forcing us to breathe in stuffy rooms shared by many other people.
Airborne microbes are biological airborne contaminants (also known as bioaerosols) like bacteria, viruses or fungi as well as airborne toxins passed from one victim to the next through the air, without physical contact, causing irritation at the very least. This usually happens when an infected subject sneezes, coughs, or just plain breathes. It is hard to prevent such a method of transmission.
Transport of Your Pathogen
Airborne microbes can move directly, from person to person through respiration, ingestion, and dermal contact or indirectly, from waste handling and loading of sewage, biosolids or animal wastes. Also, fungal spores released by soil fungi into the wind can be a natural mechanism of transportation. The concept of airborne microbes is general. People can be affected basically by any naturally occurring or human caused process that kicks up dust or other small particles that might blow in the wind.
Natural contaminants, such as wind-blown dust from arid regions (a process known as desertification), can carry bacteria and fungi. These aerosols are associated with soil or vegetation because the microorganisms are usually transported by the aerosol, or in other words, the soil particle. This process requires dry conditions because the particles need to be light weight in order to be picked up by the wind. However, dry environments are not ideal for microbial growth, therefore this method of transportation is not as common.
According to a research paper found on the official website of the EPA, or Environmental Protection Agency, F.C. Tsai, J.M. Macher and Y-Y Hung (all from California) have concluded an experiment with the following statements:
"Outdoor concentrations of airborne bacteria generally were higher than those indoors but similar in summer and winter. Bacterial concentrations indoors showed more seasonal difference, which may be due to changes in occupant dress and activities as well as ventilation patterns during the cooling and heating seasons...The preliminary results in this paper provide baseline information on the concentrations of culturable bacteria in commercial and public buildings in the United States."
However, proponents of airborne transmission argue that this division is hazy. For instance, a liquid drop five microns across can actually float for about half an hour. “Nature doesn’t create cutoff points,” says Lidia Morawska, an aerosol physicist at the Queensland University of Technology in Australia and an author of the Clinical Infectious Diseases letter.
An intense sneeze can launch a high-speed cloud of spit with droplets of all sizes as far as 27 feet. The distance traveled depends on humidity levels, wafting currents, temperature, and static electricity. Differences in mass can also help explain why pollen, which is aerodynamically buoyant, can travel for miles despite being much larger than the wet aerosols made by your sneezes.
What does the airborne squabble mean for you?
Here is what’s clear: The coronavirus jumps between people in close proximity. Whether that happens because of aerosols, droplets, or some combination, most recommendations remain the same: Avoid crowds and face-to-face chats even while wearing a mask. Masks help stanch the spray, particularly for larger droplets, so people should still wear them, but the potential for aerosol transmission means more tactics may be needed for stuffy rooms.
Altering ventilation systems can have high cost, both financially and environmentally, but some shifts are simple and inexpensive. For example, classrooms could vacate for a period between classes, with windows and doors open to bring down airborne viral levels. Marr has also translated the concerns to actions in her daily life, such as winding down the windows in a taxi.