Over the past few weeks, I have found myself becoming increasingly irritated with the continuing nature of the lockdowns. What had originally started as a 2 week recommendation has now continued for over 10 months. Around 1 month ago, I looked at the cloth mask I had been using for the prior few months. The mask which had originally been a clear white was now a greyish brown. A bit before, I had also noticed that on the morning run, there were now a lot more people out. I am in favor of people getting outside, but what stood out to me was that most of the people out were in groups. Some of this is probably personal bias, but some bitter thoughts have crossed my mind. Why am I wearing a mask around people who aren’t protecting themselves? I was told 2 weeks and I’ve now been doing this for almost a year. How long am I supposed to keep doing this? How much is wearing a mask actually helping?

Around then, I threw away the now brown cloth mask and decided to stop wearing a mask when on the morning run. When passing people, I would pull up my shirt over my nose and mouth and let it drop after. The signs around the loop mention maintaining 6 feet or wearing a mask, not both. In some ways, I am doing this out of spite. Though I’m not sure at who. As far as I can tell, there isn’t much difference between pulling up my shirt and wearing a cloth mask. Generally, no-one says anything. A bit over a week ago while doing the loop, a runner in front of me said in an angry tone ‘you need to wear a mask’. I said ‘the signs say 6 feet and when I’m passing I pull up my shirt’. He scoffed at me like I was an idiot but didn’t say anything else. Earlier today when I was rollerblading with Pico, just as we were leaving the park I heard a woman’s voice yelling ‘SIR WEAR A MASK’. I wasn’t sure where she was or if she was talking to me. I stopped and looked around. 100 feet away, I see her. She says again loudly ‘WEAR A MASK SIR DON’T YOU CARE ABOUT PEOPLE’. I’m not sure why, but for some reason her saying that made me more irritated than I like to be. I yelled back ‘6 FEET LADY’ and continued. I don’t know if she said anything back.

I don’t particularly mind being confronted on this and as of now, I don’t intend to start wearing a mask on the loops. As of now I don’t intend to start wearing a mask when outside. Some of my rationalizations include ‘It’s not actually helping’. ‘It makes it tough to breathe’. ‘I like feeling the sun on my face’. ‘I should wear a mask? Ok how long?’. ‘Those at risk have had 10 months to get an N95 to protect themselves’. ‘Wearing a mask is obviously ineffective as evidenced by the need to continue the lockdown over 10 months’. Etc. At the same time, I am aware that some of the way I am acting isn’t about wearing the mask. Instead it is related to the continuing lockdowns and the feeling I have had that it is getting in the way of my life. I think it will be useful to spend some time understanding the benefits and drawbacks of wearing a mask so that if it is worthwhile, I can start doing it again and if not, I can better communicate my reasons to those who disagree.

First, what are the benefits of wearing a mask as I know them? From what I understand, conventionally available masks are not designed to protect the wearer, only prevent the distance air travels when breathing out. Because COVID is a highly infectious airborne virus and an infected person breathing out probably leaves virions in the air and many people who are infected and capable of spreading the virus have no symptoms, the hope is if everyone wears a mask when around other people it is less likely infected air will be breathed in by those at risk or those who regularly deal with those who are at risk. This is a bit of a run-on sentence. In short, if the spread is modelled as a closed room with no air flow, wearing a mask will reduce the distance infected air travels reducing the rate of spread to only those closest to the wearer.

What are the drawbacks of wearing a mask as I know them? Beyond the inconvenience of needing to wear one when out (which to me is substantial), the primary drawback to wearing a mask lies in improper usage. For example, the way I have used masks has generally been to leave a few masks in the car for the gym and getting groceries, one in the backpack for boxing, and have a stash of masks to replace the ones in use as needed. When I have an itch on my face, I either scratch through the mask or lift it. The proper way to use a mask is to wash cloth ones whenever dirty or at least daily and to dispose of single use masks after one use. Being that the idea is to make sure breathing in and out goes through the mask, using it improperly creates an easy vector for bacteria to get into the body (breathe in air) and it also creates a suitable environment for bacteria growth (warm/moist air on each exhale).

My gut feel is that wearing a mask when indoors and interacting with strangers for an extended period of time likely helps reduce the spread of the virus. Having written out my initial assumptions and thoughts, now I think it will be useful to do some digging. Where are my initial thoughts wrong? First, COVID is not literally an airborne virus. Rather, COVID is spread via respiratory droplets naturally produced when exhaling ranging from 0.5-0.0005 millimeters in size. According to the CDC, surgical and cloth masks are between 50-80% effective at blocking respiratory droplets across this range from being released into the air. Also, because the spread is largely through droplets, wearing a mask does offer some protection to the wearer by capturing droplets not caught by the other persons mask, though from what I understand this is more theoretical than evidence based. Even if the droplets blocked is less than 100%, wearing a mask can also reduce the severity of symptoms in those who are infected by reducing the initial viral load on infection. One limitation of masks which I didn’t consider initially was fit. Masks which are looser fitting have shown to be 82%-30% as effective as better fitting masks. As such, it can generally be recommended to prioritize fit over the fabric used in the mask.

Ok. In theory, wearing a mask should reduce the amount of suspended water droplets in the air as a result of breathing by catching them in the layers of fabric. Given this is the main purpose of wearing a mask, some relevant questions include:

• What size of droplets are the most significant transmission vector which masks prevent?
• How effective are masks at capturing the droplets in this range?
• What activities which I am doing produce the most droplets in this range?
• How does the volume of droplets correlate to the likelihood of getting sick?

To address the first question, it is important to know what happens to droplets of different sizes on exhale. According to one study, the range of human respiratory droplets spans from 0.5 microns to 500 microns. 95% of which are less than 100 microns in normal breathing and a majority of which are between 4 and 8 microns. One interesting note is that even after evaporation, the droplet residue will remain in the air and is likely capable of causing infection. In general, droplets larger than 100 microns will settle on a surface before evaporating while smaller droplets are likely to evaporate before reaching the ground. The ratio which remains suspended is related to the relative humidity of the air. Once particulates are less than 10 microns in size, they generally evaporate extremely quickly to a droplet nuclei with a size of around 0.6-5 microns.

Size	Approximate Time to Fall	Time to Evaporate (low, high humidity)
100 microns	3 seconds	(10, 60) seconds
10 microns	5 minutes	(0.05, 0.6) seconds
1 micron	8 hours	(0.001, 0.008) seconds
Nuclei	?	N/A

How effective are masks at addressing the range of droplet sizes smaller than 100 microns? I am having difficulty finding studies on the higher end of droplet size (greater than a few microns). Possibly this is because most fabrics perform extremely well once droplets are on the order of 0.1 millimeters. Also, most of the studies focus on particulate size rather than droplet size. Most likely, droplets will perform better than particulates assuming the fabric is absorbent. Still, understanding how different fabrics perform at the smaller scale may help me better understand when and how I should wear a mask.

Fabric	Efficiency ~0.5 microns (500nm)	Efficiency ~5 microns (5000nm)
Silk – 1 Layer	40-43%	57-62%
Silk – 4 Layers	80%	92%
Cotton – 80 TPI	55%	7-13%
Cotton – 600 TPI	94%	97%
Flannel	22-28%	49%
Chiffon	54%	75-78%
Surgical	96% (with gap 36-44%)	99% (with gap 40-50%)

What does this mean? One segment which stands out is the high effectiveness of properly worn surgical masks in blocking particulates. If wearing a surgical mask captures 96-99% of particles between 0.5 and 5 microns and the size of particulates even after evaporation is 0.6 to 5 microns, it seems like recommending masks only for those who are at risk should be sufficient though from what I understand professional grade masks are in short supply and most people may not know how to properly wear and use them. Also, another study suggests that the efficacy of masks on exhale is much more efficient than on inhale. Another segment which stands out is the poor efficiency of low thread count cotton. An argument can be made that the person who scoffed at me on the run was right assuming cotton is no more efficient at blocking a droplet than a particulate.

Now that I have a better understanding of the mechanism of masks and the behavior of droplets, it may be worth seeing how different activities impact how I respire. One study looking at aerosol emission during human speech, includes a breakdown of how many droplets are produced doing different activities.

Activity	Particles per volume per second (m3)	Geometric Mean Particle Size (microns)
Nose breathing	0-5,000	0.7-0.9
Mouth breathing (normal)	0-20,000	0.72-0.99
Mouth breathing (fast)	0-60,000	0.71-0.92
Quiet talking	40,000-200,000	0.92-1.1
Intermediate talking	50,000-280,000	0.92-1.23
Loud talking	130,000-390,000	0.94-1.27

The geometric mean is the nth root of the product of n numbers. In this context, the value represents on average how much larger the next largest particle is than the current particle (exponential growth). The data suggests that talking normally produces 5 times the number of particles and with a wider range of sizes than breathing out quickly though I don’t see data on the smallest and largest particle size. Regarding how much exposure is needed before being infected there isn’t much data, however based on data from other viruses the likelihood of getting sick seems to be related to the quantity of exposure. For SARS this is a few hundred particles. For MERS, this is several thousand particles. In general, the larger the particle exhaled the more virus particles it will contain and it is reasonable to expect the relationship to be cubic to the radius of the particle.

Modeling particles as a sphere, a particle 5 microns in diameter likely contains 16 times the number of virus particulates as one which is 1 micron. Another factor impacting exposure is ventilation. One study which looked at how long droplets with an average size of 5 microns lasted in rooms of varying ventilation found that in rooms with no ventilation, it took 300 seconds for the number of aerosolized particles to be halved. In a room with mechanical ventilation, it took 84 seconds seconds for the number of particles to be halved. In a room with mechanical ventilation and an open door and window, it took 30 seconds for the number of particles to be halved. Given this, the ideal super-spreader event is one where many people are grouped closely together in an unventilated dry room without masks playing an endless version of the ‘penis’ game. Ok, so being outside is clearly more ventilated than a mechanically ventilated room (similar idea to the fan in a bathroom) and most likely reduces the particle concentration faster. According to Prof Paul Hunter, the risk of transmission outdoors is 18.7 times less likely than indoors.

I think what most bothered me about what the lady said was that I felt like she was calling me a bad person. The next morning, I walked the loop instead of running as usual and honestly I felt guilty each time I passed people going the other way. Am I the bad guy? I made the decision to stop wearing a mask when running not because it isn’t helping but because it is annoying, I don’t like that I have been strung along for almost a year, and it is only recently that I have become aware of how much this situation has been getting in the way of me living the life I want to. Before all of this started, on the morning run I would smile and wave at everyone who was going the opposite direction. Not because I knew them, but because at that moment we were all enjoying the day together. I think it was pretty much when the mask mandates started that in my mind a switch flipped. All of the sudden, encounters were annoying obstacles. A few seconds of trying to gasp for air through a dirty cloth before pulling it back down and continuing. It really is a shame I allowed my attitude toward people to change like that.

Through doing this I have learned a good amount about why we are supposed to wear masks and the airborne disease transmission vector. Knowing what I do now, what will I do differently going forward? As shown above, pulling my shirt over my nose doesn’t really help much and may actually make the situation worse by causing particles to evaporate to a smaller size with the same concentration of virions although being outside likely reduces the possible effect to insignificant levels. Going forward, I will go back to covering my mouth and nose with a more effective fabric when passing people on the path and 6 feet is not an option.