Thread by @ToshiAkima

1. I am hearing more and more stories of people catching COVID on a plane while wearing an N95 mask. There are numerous reasons for this and we'll go through them to help you avoid getting COVID

2. During boarding, the air filtration system is usually not running. You know how stuffy it can get on board a plane on a hot day, when departure is delayed. Before take-off, the CO2 levels climb to eye-watering levels (it should be less than 700ppm)

3. Due to worker absenteeism, there are delays in take-off, which means longer periods with stratospheric CO2 levels. This leads to more crew getting COVID and an increase in take-off delays. It's a vicious cycle cbsnews.com/news/airlines-…

4. By getting rid of the mask mandate, airlines are failing to provide a safe environment for their employees and customers. Apparently, turning planes into COVID Petri dishes is “good for business”. The industry solution is to deny it is happening. This enjoys union support🤡

5. There is evidence that in such high-risk scenarios, N95 masks alone may be insufficient unless an air filtration system is operational. This means that when one-way masking on a plane, a P100 elastomeric is preferred academic.oup.com/jid/advance-ar…

6. Another part of the problem identified in that paper is that most crew and passengers have not been fit-tested for their N95 masks. Elastomerics have a much higher pass rate on fit testing. …ccess.s3-ap-southeast-2.amazonaws.com/AustralianAnae…

7. You can also do a home qualitative fittest if you really want to make sure you have a proper seal on your elastomeric mask. This thread shows you how to set up a testing system at home

8. The minimum is a negative pressure test. Cover the filter with both hands and sharp inhale to see if there are leaks. Repeat with head up-down, left-right. See how far you can open your mouth before a leak develops (all masks have their limit)

9. Also do a positive pressure test by covering the filters with both hands and exhale. This is demonstrated in this video of the Dräger X-plore 2100. Repeat with head up-down, left-right, plus with mouth a little open as when speaking

10. My first recommendation for P100 elastomerics is the @DentecSafety Comfort-Air NxMD (review coming). The GVS Ellipse P100 is popular. The Dräger X-plore 2100 is cost-effective. The 3M 6000 is widely available. The Sundström SR100 has a high pass-rate cleanaircrew.org/masks/

11. The non plus ultra solution is a @cleanspacehc Halo PAPR, here modelled with and without an exhalation filter. But it is rather expensive despite its recent price drop. If you want the first-class option, this is it.

12. All this could be avoided if there were mandates for filtration during boarding, taxi and takeoff, coupled with universal mask-wearing by staff and passengers. Two-way masking plus air filtration may mean P100 filters are no longer necessary. Until then, P100 filters stay on

Postscript on long flights: a Halo PAPR needs recharging every 8hrs, and the bulky motor sits around the neck. Ensure your elastomeric doesn't rub during prolonged wear, causing ulceration of the nose/face

Postscript on eye protection: there is modest evidence for this. It's preferable that you get a reasonable seal from goggles, rather than wearing open frames or face shields with gaps. Aerosol, like smoke, gets in your eyes uvex-safety.com.au/en/products/sa…

Another comment. The argument that the airport chaos is due to the demand for services outstripping supply, is simply not tenable. If that is the case, then that would be an admission of outright fraud

Another postscript. Airlines vary in the quality of their engineering-based management of onboard air quality. Do your research before flying and, as a consumer, demand that they upgrade their aerosol mitigation systems