Is your face mask in line with the latest WHO guidelines?
As latest guidelines recommend face masks even for the general public, a look at which types of masks you can use and the degree of safety they offer.
In April, the World Health Organisation (WHO) had maintained in its advice for the general public that there wasn’t enough scientific backing for or against the use of masks for healthy people in the community. It had recommended that medical masks be worn by people who are sick and by those caring for them, as a Reuters report says.
However, in its recent interim guidance and “advice on the use of masks in the context of COVID-19", the international public health body states that to prevent the spread of infection effectively in areas of community transmission, governments and decision-makers should encourage the public to wear masks in specific situations and settings. This communication, released in June, is backed by a recent analysis (published in the medical journal The Lancet) of 172 studies from six continents, which found that the use of face masks could result in significant reduction in the risk of infection.
So what are the different kinds of masks out there and what degree of safety can they offer?
Ideal for: Medical and healthcare workers handling covid-19 patients, with additional protection, including visors, face shields and goggles.
Filtering facepiece respirators like N95s are tailor-made for medical professionals and healthcare workers, especially so during the covid-19 pandemic. It’s important to remember that these dome-shaped masks are a critical part of personal protective equipment or PPE, which are used to protect the wearer from airborne particles from contaminating their face. According to the US Food and Drug Administration (FDA), the ‘N95' designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (0.3 micron) test particles.
As a general precaution, the FDA says that people with any chronic respiratory or cardiac conditions that make breathing difficult should check with their healthcare provider before using an N95 respirator because it can make breathing more difficult for the wearer due to its tight fitting. Recent reports have also highlighted how a certain type of N95 mask, with valves, can be harmful not only for users but others around them. “Masks with exhale valves should not be used. That’s because unfiltered air from the user passes through the valves," says Jai Dhar Gupta, founder, Nirvana Being, the Delhi-based air pollution solutions company.
SURGICAL OR PROCEDURE MASKS
Ideal for: Medical and healthcare workers, with additional protection
Surgical face masks also make up an important part of PPEs. These are mostly flat, pleated, loose-fitted and, as per the FDA, are disposable devices that create a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. These can be affixed to the head with straps that go around the ears or head or both. Do remember that even though these are often referred to as face masks, not all face masks are regulated as surgical masks.
Such masks are made in different levels of thickness and they aim to balance high filtration, adequate breathability and optionally, fluid penetration resistance, the WHO guidelines add. The Lancet study explains that both N95 and surgical masks have a stronger association with protection compared with single-layer masks. Since these masks are disposable, they are sometimes an attractive option for the general user. But amid a global shortage of PPE, including surgical masks, the WHO guidelines recommend encouraging the public to create their own fabric masks that can be safely reused. This could also reduce costs, waste and contribute to sustainability.
NON-MEDICAL CLOTH FACE MASKS OR COVERINGS
Ideal for: The general public, especially in settings where social distancing cannot be practised
One of the key highlights from the latest WHO guidelines is that now it is recommended for the general public and healthy individuals to wear a non-medical mask. But the WHO makes it clear that even non-medical cloth face masks need a minimum of three layers. “A minimum of three layers is required for non-medical masks, depending on the fabric used. The innermost layer of the mask is in contact with the wearer’s face. The outermost layer is exposed to the environment," the advisory adds.
The advisory also explains the kind of material or ‘fabric’ can be used to make such masks. The ideal combination of material for non-medical masks should include three layers: an innermost layer of a hydrophilic material (for example, cotton or cotton blends; an outermost layer made of hydrophobic material (like polypropylene, polyester, or their blends)— these can limit external contamination from penetration through to the wearer’s nose and mouth. Third, a middle hydrophobic layer of synthetic non-woven material such as polypropylene or a cotton layer that may enhance filtration or retain droplets.
Gupta says there are two important things the general public should remember while using masks. “Don’t go for the disposable ones," he says. “Instead, buy a reusable and washable mask." If you are making your own masks, then ensure that your face is sealed properly. “The curvature of the nose and cheek bones are one of the most difficult parts of the face. Use a noseband in the mask, if possible. You’ll have to ensure the mask seals your face properly in these areas because air will always find a way through these gaps," he adds .
FIRST PUBLISHED08.06.2020 | 06:45 PM IST