I went to the US from Canada to get the JN.1 Novavax booster because no mRNA for me. We drove in on a rented car and I got my passport last-minute.

There are some things I learned in the process and other things I wish I did differently. 🧵 A friend advised me to tell the truth at the border, despite what some people felt on here. That worked well.

Thing is, there isn’t a good lie to come up with to explain crossing the border for just a couple hours. I swear the officers talk to each other, too. If you’re going shopping, you’ll need to do some SERIOUS shopping. Usually, people go for an entire day and load up their whole car. So I don’t think that would work as a reason. Last-minute passports and rental cars are also a no-go for this kind of lie. Telling the truth is just safer (but the vulnerability sucks for sure!).

How Much Can a Fashion Earloop Mask Protect You? (The Upgrade Edition) (Trifolds Only)

Let’s talk about masks that anyone might want to wear, no matter what they believe in, just because some of them actually look cute.

***Warning: This one’s super experimental, but there’s some hopefully useful default fit info for you here, too!

I tested a bunch of popular trifold KN95s and KF94s to see how well they fit my face. I then made some mods to them and tested every step of the way.

Overall, these respirators/masks usually have really good filtration and SOMETIMES fit surprisingly well... But you basically have to fit test every single batch or even piece, especially if you’re buying obscure-looking stuff of eBay or Amazon.

I hope I included your favourites. If not, I’m accepting requests for the next one! 🧵 I used my oldie PortaCount 8020A to fit test the masks (which I then tried to convert into respirators 😉).

A typical Occupational Safety and Health Administration (OSHA) fit testing protocol includes eight exercises: Normal breathing, Deep breathing, Head side to side, Head up and down, Speaking out loud, Bending, and back to Normal breathing. Each exercise is one minute long, adding up to eight minutes total.

The scores included are means across one or more exercises. I would always start with normal breathing. Whenever I got a higher-than-expected score on that, I would keep moving through next steps of the protocol to get a better picture. I usually stopped at the first four exercises max once I could see a pattern in the scores. And there were times I ended up doing the whole OSHA protocol.

So some of the scores are single exercise scores. Others are composites of no more than four exercises.

How much can you re-use a Dräger 1950 respirator?

I noticed how quickly they failed when I used one on myself. Then, the same thing happened with a friend. I could not believe it, because they fit so many people SO well and are often their best respirator when I fit test them.

There is at least one other person in our fit testing community who tested it and found how quickly it breaks down compared to a 3M Aura:

https://x.com/kettlefrogbsky/status/1781618630842519958

I decided to formally test this myself with two “specimens” of this respirator in size small. I always wrote down each exact time I put them on and took them off as soon as possible.

Mostly, I wore them for running errands, fit testing other people, cooking, and cleaning. I don’t usually wear regular N95s at my physically intensive job. I did manage to wear the first one for a few hours there, though.

I installed a SIP valve in both of them before my first use. The valves, installed carefully, do not affect fit based on my previous tests.

I took a full, long shower in an earloop Zimi ZM9541F after 10 hours of prior wear with a SIP valve installed. I then fit tested the totally soaked thing with my PortaCount 8020A (always in N99 mode).

The scores dropped, but it still gave really good protection. I did not collect proper controls for this one (prior to wear and SIP valve installation), unfortunately.

My fit factor for a fresh filter without a SIP valve on OSHA protocol was 55 with the grimace exercise, which is usually not counted, and 57 without. So 98.1% protection.

Best Quality Earloops: Rapid Fire OSHA testing edition.

Can an earloop mask be protective?

(Disclaimer: These results are for my face only. I also have a Roman nose, which can make nose leaks more likely).

Scores are harmonized mean fit factors (HMFF), grimace exercise score taken out. Worst to best:

*Wellbefore 3D Pro Black KN95 - 11.68 HMFF (8.6% leak, 91.4% effectiveness)

*Breatheteq medium black KN95 - 12.91 HMFF (8.3% leak, 91.7% effectiveness)

*Canadamasq CA-N95F medium - 19.93 HMFF (5.26% leak, 94.74% effectiveness)

*ZiMi ZM9541F black, mod tension 450mm each loop - 11.69 HMFF (1.75% leak, 98.25% effectiveness).

It’s pool and beach season! Will a respirator work for swimming and water parks (or shower sans hair washing)?

Using my PortaCount 8020A, I tested the most accessible & affordable water-resistant respirator, 3M Aura 1870+, after 6 and 8 hours of wear at the pool (1.5hrs total of swimming) across a month. I did install a SIP valve in it – you get thirsty!

To see if you really need a water-resistant version, I then tested the 1870+ against a non-water resistant 3M Aura respirator with similar rubbery straps, the 9205+.

The results were surprisingly good all around.

(photo is a fresh and used 1870+ side by side) Here are my 1870+ scores for swimming. Thank you @fittesttheplanet for the little probe plug that made re-testing a probed one possible!

I also wore swim goggles during all “soaks”.

Baseline - Fresh 3M 1870+, no SIP valve, OSHA protocol

Normal breath: 144
Deep breath: 103
Head side to side: 167
Head up and down: 120
Speaking: 49
Grimace: 179
Reaching: 88
Normal breath: 145

Score w/ grimace: 106.34 (99.06% of air filtered)
Score w/o grimace: 100.51 (99.01% filtered)

Note: I have tested the SIP valve in the past and it did not have any impact on fit testing scores. The focus here is on trends across time. It is possible that I installed it differently this time, but I don’t think this is likely with the follow-up scores. I did not have a way to seal the probe when I started using the respirator.