📍~100% of tiny particles (<0.1μm) through Brownian diffusion
📍~100% of the larger particles (>1.0μm) through interception
📍medium particles (~0.3μm) are trickier but an N95 mask will still filter out 95% of these.
To understand this in more detail, this brilliant video from @minutephysics explains the genius physics behind N95 masks and how they work to protect you against even the tiniest fine particles.
TLDR: They work more like magnets than like sieves.
There are a number of mechanisms in action within N95 masks which contribute to their filtration efficiency, including:
Oh, and just in case you’re getting confused about all the mask terminology (N95, N99, FFP2, FFP3 etc), this is a really useful explainer from the good folks @SmartAirFilters:
Broadly speaking, an N95 is similar to the European FFP2 standard.
This is not a particularly new idea; it’s been discussed in scientific circles for years already.
Back in early 2023, the World Health Network (@TheWHN) published this article which summarised the latest research on Covid’s impact on the immune system.
The guidance is clear that those self-isolating at home should NOT wait for symptoms before taking precautions.
For the ENTIRE 42-day quarantine, they should:
▪️Avoid contact with other household members
▪️Remain in a separate room
▪️If contact is unavoidable, wear a respirator
🚨Clinically Vulnerable Families (@cv_cev) have issued a press release calling for the government to immediately publish the full operational & clinical arrangements for passengers & close contacts linked to the MV Hondius outbreak.
I’ve just listened to the health update from the US Nebraska Health Officials 🇺🇸
A few points of interest:
1/ in addition to the US passenger who tested positive & the one showing symptoms, it seems there is ANOTHER passenger who may have tested positive.
2/ Passengers currently in the Nebraska quarantine unit will spend a few days there being assessed.
If they remain symptom free & have support available at home to isolate safely, they’ll have the choice to complete the 42-day isolation either at home or in the quarantine unit.
3/ When asked about the US passengers who left the ship in St Helena on 24 Apr (at the same time at the Dutch woman who was symptomatic & sadly died on 26 Apr), they confirmed that these passengers have all been traced & are being monitored - but seems they’re NOT self-isolating.
Following my thread yesterday which criticised aspects of the WHO’s strategy, I’m pleased to see they’ve done a 180° turn in the updated guidance published today:
…and ALL high-risk contacts will now be required to ISOLATE in a designated facility or at home (depending on each country’s capabilities) for 42 days from last known exposure…
…and for the MV Hondius passengers & crew, the last day of exposure is the date of disembarkation.
So for the passengers & crew leaving the ship today, the clock for their 42 days in isolation starts ticking TODAY…
…and their isolation & monitoring will end on 21 June.
Following the WHO press briefing, I wanted to compile a thread with the key points.
1/ ISOLATION OF PASSENGERS
Concerningly, it seems the WHO are NOT recommending to isolate cruise ship passengers (even high-risk contacts) UNLESS they develop symptoms.
Just to quickly recap, it has been confirmed that the passengers & crew (including the 30 who disembarked on 24 April in St Helena) come from a total of 28 different countries.
The full breakdown of countries for both passengers 🟥 & crew 🟦 is detailed below ⬇️
When the 146 people remaining on the ship are repatriated to their home countries, each country will adopt their own local protocols.