Tag Archives: public health

Coronavirus, News, Observation

What is the best mask for COVID-19? A mechanical engineer explains the science after 2 years of testing masks in his lab

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1. What changed in the CDC guidelines?

The CDC currently recommends that you “wear the most protective mask you can that fits well and that you will wear consistently.” The question, then, is what type of mask offers the best protection for you – by filtering the air you breathe in – and for those around you – by filtering the air you breathe out?

The CDC’s updated guidelines clearly lay out the hierarchy of protection: “Loosely woven cloth products provide the least protection, layered finely woven products offer more protection, well-fitting disposable surgical masks and KN95s offer even more protection, and well-fitting NIOSH-approved respirators (including N95s) offer the highest level of protection.”

From a performance standpoint, the N95 and KN95 masks are the best option. While supply chain limitations led to the CDC recommending people not wear N95s early in the pandemic, today they are easily obtainable and should be your first choice if you want the most protection.

The biggest change in the new guidelines has to do with cloth masks. Previous guidance from the CDC had said that some cloth masks could offer acceptable levels of protection. The new guidance still acknowledges that cloth masks can offer a small amount of protection but places them at the very bottom of the bunch.

N95 masks are made from a tangled web of tiny plastic fibers that are very effective at trapping particles. Alexander Klepnev via Wikimedia Commons, CC BY-SA

2. What’s the difference between N95, surgical and cloth mask materials?

The effectiveness of a mask – how much protection a mask provides the wearer – is a combination of two major elements. First, there’s the ability of the material to capture particles. The second factor is the fraction of inhaled or exhaled air leaking out from around the mask – essentially, how well a mask fits. 

Most mask materials can be thought of as a tangled net of small fibers. Particles passing through a mask are stopped when they physically touch one of those fibers. N95s, KN95s and surgical masks are purpose-built to be effective at removing particles from air. Their fibers are typically made from melt-blown plastics, often polypropylene, and the strands are tiny – often less than four thousandths of an inch (10 micrometers) in diameter – or approximately one third the width of a human hair. These small fibers create a large amount of surface area within the mask for filtering and collecting particles. Although the specific construction and thickness of the materials used in N95, KN95 and surgical masks can vary, the filter media used are often quite similar.

These fibers are very tightly packed together so the gaps a particle must navigate through are very small. This results in a high probability that particles will end up touching and sticking to a fiber as they pass through a mask. These polypropylene materials also often have a static charge that can help attract and catch particles. 

Cloth masks are typically made of common woven materials such as cotton or polyester. The fibers are often large and less densely packed together, meaning particles can easily pass through the material. Adding more layers can help, but stacking layers has a diminishing return and the performance of a cloth mask, even with multiple layers, will still typically not match that of surgical mask or N95.

3. How much does fit matter for masks?

Fit is the other major component in how effective a mask is. Even if the materials used in a mask were perfect and it removed all particles from the air that passed through it, a mask can offer protection only if it doesn’t leak.

When you breathe in and out, air will always take the path of least resistance. If there are any gaps between a mask and someone’s face, a substantial fraction of every breath will seep out through those gaps and the mask will provide relatively little protection. 

Many cloth mask designs simply do not seal well. They are not stiff enough to push against the face, there are gaps where the mask doesn’t even come in contact with the face and it is not possible to cinch them tightly enough against the skin to form a decent seal.

But leaking is a concern for all masks. Although the materials used in surgical masks are quite effective, they often bunch and fold on the sides. These gaps provide an easy route for air and particles to leak out. Knotting and tucking surgical masks or wearing a cloth mask over a surgical mask can both significantly reduce leakage.

N95 masks aren’t immune to this problem either; if the nose clip isn’t securely pushed against your face, the mask is leaking. What makes N95s unique is that a specific requirement of the N95 certification process is making sure the masks can form a good seal.

4. What is different about omicron?

The mechanics of how masks function is likely no different for omicron than any other variant. The difference is that the omicron variant is more easily transmitted than previous variants. This high level of infectiousness makes wearing good-quality masks and wearing them correctly to limit the chances of catching or spreading the coronavirus that much more critical.

Unfortunately, the attributes that make for a good mask are the very things that make masks uncomfortable and not very stylish. If your cloth mask is comfy and light and feels like you are wearing nothing at all, it probably isn’t doing much to keep you and others safe from the coronavirus. The protection offered by a high-quality, well-fitting N95 or KN95 is the best. Surgical masks can be very effective at filtering out particles, but getting them to fit correctly can be tricky and makes the overall protection they will provide you questionable. If you have other options, cloth masks should be a last choice.

Originally published on The Conversation by Christian L’Orange and republished under a Creative Commons License

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Climate Solutions, Coronavirus, News, Observation

Climate Emergency, Vaccine Monopolies, and Fiscal Blindness: The Fight Against Inequality Is the Only Way Out

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Above: Photo Credit: Photo Collage / Lynxotic

If we are failing to meet our commitments, it is because of a handful of the richest people on the planet refuse to pay their taxes.

2021 will perhaps be remembered as the year when the great powers demonstrated their inability to assume their responsibilities to prevent the world from sinking into the abyss. I am thinking of course of the 26th United Nations Climate Change Conference (COP26) in Glasgow. After having used up the available atmospheric space to develop, the industrialized countries reaffirmed their refusal to honour this climate debt, even though global warming has become an existential issue.

And this is not all. I also refer to the calamitous management of the Covid-19 pandemic. Rich countries have monopolized and hoarded vaccines, and then locked themselves in surreal debates about third doses or the comparative merits of this or that vaccine. This strategy sows death and hinders economic recovery in vaccine-deprived countries, while making them fabulous playgrounds for the proliferation of more contagious, more deadly and more resistant variants that do not care about borders. 

If we add the tax evasion of the ultra-rich using tax havens, we arrive at a total loss of US $483 billion.

Finally, I also want to talk about another agreement imposed by the Northern capitals, apparently more technical, but which symbolizes their selfishness and blindness: the one on the taxation of multinationals. Concluded in October, it is a gigantic undertaking, the first reform of the international tax system born in the 1920s, totally obsolete in a globalized economy. Thanks to its loopholes, multinationals cause States to lose some US $312 billion in tax revenue each year, according to the “State of Tax Justice in 2021” just published by the Tax Justice Network, the Global Alliance for Tax Justice and Public Services International.

If we add the tax evasion of the ultra-rich using tax havens, we arrive at a total loss of US $483 billion. This is enough, the report reminds us, to cover more than three times the cost of a complete vaccination programme against Covid-19 for the entire world population. In absolute terms, rich countries lose the most tax resources. But this loss of revenue weighs more heavily on the accounts of the less privileged: it represents 10% of the annual health budget in industrialized countries, compared to 48% in developing ones. And make no mistake, the people responsible for this plundering are not the tropical islands lined with palm trees. They are mostly in Europe, first and foremost in the United Kingdom, which, with its network of overseas territories and “Crown Dependencies”, is responsible for 39% of global losses.

In this context, the agreement signed in October is a missed opportunity. Rich countries, convinced that complying with the demands of their multinationals was the best way to serve the national interest, put themselves behind the adoption of a global minimum corporate tax of 15%. The objective, in theory, is to put an end to the devastating tax competition between countries. Multinationals would no longer have an interest in declaring their profits in tax havens, since they would have to pay the difference with the global minimum tax.

In reality, at 15%, the rate is so low that a reform aimed at forcing multinationals to pay their fair share of taxes risks having the opposite effect, by forcing developing countries, where tax levels are higher, to lower them to match the rest of the world, causing a further drop in their revenues. It is no coincidence that Ireland, the European tax haven par excellence, has graciously complied with this new regulation.

Taxation is the very expression of solidarity. In this case, the absence of solidarity. A global tax of 15% on the profits of multinationals will only generate US $150 billion, which, according to the distribution criteria adopted, will go, as a priority, to rich countries. If ambition had prevailed, with a rate of 21% for example, we would have obtained an increase in tax revenues of US $250 billion. With a rate of 25%, tax revenues would have jumped by US $500 billion, as recommended by ICRICT, the Independent Commission on the Reform of International Corporate Taxation, of which I am a member, along with economists such as Joseph Stiglitz, Thomas Piketty, Gabriel Zucman and Jayati Ghosh.

Making multinationals pay their fair share of taxes, fighting climate change, dealing with Covid-19 and future pandemics: in reality, everything is linked. While the virus is on the rise again with the arrival of winter in the northern hemisphere, the boomerang effect of the vaccine monopolies no longer needs to be shown or explained. As for the climate emergency, we know from a recent study by the World Inequality Lab that the map of carbon pollution is perfectly in line with that of economic disparities. The richest 10% of the world’s population emit nearly 48% of the world’s emissions—the richest 1% produce 17% of the total!—while the poorest half of the world’s population is responsible for only 12%.

This gap is obvious between countries, but also within them. In the United States, the United Kingdom, Germany and France, the emissions levels of the poorest half of the population are already approaching the per capita targets for 2030. If we are failing to meet our commitments, it is because of a handful of the richest people, the same people who do not pay their taxes. It is time for our elites to realize that fighting inequality on all fronts—health, climate and tax—is our only way out. Otherwise, there is no salvation for humanity—and it is no longer a hyperbole.

Originally published on Common Dreams by EVA JOLY and republished under under Creative Commons license (CC BY-NC-ND 3.0)

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