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CHAPTER 1
What Is PAPR for Everyone?
PAPR for Everyone (in Japanese, the "Distancing-Free Mask") is a concept for turning the positive-pressure PAPRs used in health care and industry into devices the general public can use every day, as an alternative to stay-at-home restrictions in a pandemic. It was first announced to the press on 7 July 2020.
How a positive-pressure PAPR works
- A fan draws in outside air, a HEPA filter purifies it, and the air is supplied into a hood or helmet. HEPA filters capture at least 99.97% of 0.3 µm particles.
- Because the breathing zone is kept at a higher pressure than outside (positive pressure), air flows outwards through any gaps, and unfiltered air has difficulty getting in.
- The principle and technology are established, but until now PAPRs have been specialised, expensive equipment for health-care workers and industry.
| Device | Assigned protection factor (APF) | Meaning |
|---|
| Medical face mask (properly fitted) | APF 10 | About 1/10 of ambient concentration |
| Positive-pressure PAPR (hood/helmet) | APF 1000 | About 1/1000 under specified fit and operating conditions |
A third axis of countermeasures
| Countermeasure | What it acts on | Characteristics |
|---|
| Movement restrictions and lockdown | Reduce contact between people | Large economic and social costs |
| Vaccines and drugs | Reduce infection and severe disease | Must be developed for each pathogen; not available just after emergence |
| Positive-pressure exposure control (PAPR) | Reduce inhalation of infectious aerosols itself | Potentially usable from the moment any pathogen emerges; effectiveness not yet demonstrated and must be evaluated |
How it would be used in society
- Not "stay home" but "go out wearing a PAPR". Instead of stay-at-home requests or curfews, going out is permitted on condition of wearing a PAPR (Chapter 3).
- Not everyone needs to wear one all the time. Models show that wear by part of the population, or partial wear by everyone, could bring the reproduction number below 1 (Chapter 3).
- People choose when to take it off. Each person receives an allowance of mask-off time and decides when and where to use it (Chapter 5).
What this concept does not claim
- It does not call for immediate deployment or a uniform obligation to wear PAPRs.
- Real-world infection prevention, safety of long-term wear, sustained use, cost and equity have not yet been demonstrated. That is exactly why it proposes formal evaluation starting in non-emergency times (Chapter 6).
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Measures for the Next Pandemic: engineering and social infrastructure for controlling infection without stopping society | Yusaku Fujii (Gunma University)
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