Masks and Viruses

How do N95 masks block SARS-CoV-2?
N95 masks are designed to remove more than 95% of all particles that are at least 0.3 microns (µm) in diameter. In fact, measurements of the particle filtration efficiency of N95 masks show that they are capable of filtering ≈99.8% of particles with a diameter of ≈0.1 μm (Rengasamy et al., 2017). SARS-CoV-2 is an enveloped virus ≈0.1 μm in diameter, so N95 masks are capable of filtering most free virions, but they do more than that. How so? Viruses are often transmitted through respiratory droplets produced by coughing and sneezing. Respiratory droplets are usually divided into two size bins, large droplets (>5 μm in diameter) that fall rapidly to the ground and are thus transmitted only over short distances, and small droplets (≤5 μm in diameter). Small droplets can evaporate into 'droplet nuclei', remain suspended in air for significant periods of time and could be inhaled. Some viruses, such as measles, can be transmitted by droplet nuclei (Tellier et al., 2019). Larger droplets are also known to transmit viruses, usually by settling onto surfaces that are touched and transported by hands onto mucosal membranes such as the eyes, nose and mouth (CDC, 2020). The characteristic diameter of large droplets produced by sneezing is ~100 μm (Han et al., 2013), while the diameter of droplet nuclei produced by coughing is on the order of ~1 μm (Yang et al., 2007). At present, it is unclear whether surfaces or air are the dominant mode of SARS-CoV-2 transmission, but N95 masks should provide some protection against both (Jefferson et al., 2009; Leung et al., 2020).

SARS-CoV-2 (COVID-19) by the numbers

 

People forget that these masks provide protection (PF10) for alpha particles (3.6 fremi). Granted, not much protection BUT if they provide some protection for particles that are .00000000036 um then they provide even more protection for viruses that are .1 um.

 

Initially, there was limited evidence to support broad masking policies for the general public, and the Centers for Disease Control and Prevention recommended masks only for those infected and medical providers treating them. On April 3, 2020, the CDC reversed course and recommended that everyone wear face coverings in public, citing new data that showed a "significant portion" of people infected with the coronavirus lack symptoms but can spread the virus to others...



In reviewing our work on masking, we have found that false and misleading claims about face masks tend to fall into four categories of misinformation: distortions of science, misrepresentation of government guidance, claims that mask-wearing has been proven to be ineffective and claims that mask-wearing increases your health risk.

There is some overlap of categories. For example, claims that distort scientific research do so to conclude, incorrectly, that masks have proven to be ineffective or even dangerous.

Below we summarize some of our work over the past 16 months, based on the categories of misinformation about masking.

Fact Check: Debunking misinformation about face masks

 

I agree, @Salty . But that is not the role of the CDC.

The safe thing to do with ionizing radiation is to avoid it. But I work in a radioactive area, so other measures are used not to prevent But minimize exposure.

Masks are effective. They work. But not everyone can wear them and provisions need to be made.

It took me forever to find a mask I could wear without almost passing out. They claim this mask is better than most, but I doubt it as I can breathe in it.

And for every policy there are exceptions to policies.

 

I agree about the Feds. I'm just saying we have known for years that masks, handwashing, and social distancing are effective tools to protect against the spread of respiratory viruses.

I'm not advocating for a mask policy. I do not mind companies requiring unvaccinated people wear masks because the science has shown they are more apt to spread covid. But I do not think the federal government should mandate masks - or vacvines - outside of their authority.

 

You can also duct tape your mouth and put cotton balls in your nose. I do not know the protection value, but in theory it'd work....I think.

 

I don't know about quilt scraps. Here most wear P-95 type masks or equivalent (but this is a DOE site). I don't wear masks when I am not at work. At work I wear the shema-97 mask because they are comfortable, I can breathe, and they are approved (and if those 3 are met, I don't really care how good they work).

 

We are wearing masks because of the unvaccinated. The vaccinated can spread covid but are less likely. We have to wear masks because the unvaccinated matter as well. They are human beings. We also want to decrease our chances of being infected, and cstastically this would be by unvaccinated people.

Bottom line is the unvaccinated created this problem so who cares if they don't like the solution?

Like you said, legitimate masks work.