Face Masks: Effective Pollution Protection?

Face masks have become an increasingly common sight around the world, especially in Asia, as people try to protect themselves from air pollution. Air pollution is a serious issue, with the World Health Organisation estimating that 4.2 million people die every year from exposure to it. While some experts recommend avoiding busy roads and polluted cities altogether, others suggest that face masks can offer some protection. However, it is important to note that not all masks are created equal, and their effectiveness depends on various factors such as the type of mask, the fit, and the level of pollution. So, do facemasks work against pollution?

N95 respirators are the gold standard

Face masks are designed to protect against "particulate matter" (PM), which is also called particle pollution. PM 2.5 particles are especially harmful to humans as they can penetrate deep into the lungs and travel to the alveoli, impairing lung function.

N95 respirators are considered the gold standard for pandemic protection. They are designed to achieve a very close facial fit and the "N95" designation means that the respirator blocks at least 95% of very small test particles. All N95 respirators on the market must meet the filtration standards required by NIOSH. SoftSeal N95 Respirators, for example, are designed with a patented 360-degree medical-grade silicone seal that conforms to and provides a comfortable seal to the face. They have been recognized by Popular Science and the National Hardware Show and were highlighted in the Boston Globe as a better mask to wear during the pandemic.

During the COVID-19 pandemic, there was a global shortage of N95 masks, which led to innovative solutions such as 3D printing and sewing homemade masks. However, the FDA cautioned that while 3D-printed PPE may provide a physical barrier, it is unlikely to provide the same fluid barrier and air filtration protection as FDA-cleared N95 respirators.

In addition to their effectiveness in protecting against viruses, N95 respirators can also provide protection against air pollution. A 2018 study by Case Western Reserve University School of Medicine examined whether N95 respirators offer effective protection against air pollution in China, where pollution levels are high.

Cloth masks may provide a false sense of security

Richard Peltier, a professor at the University of Massachusetts, Amherst, in the Department of Public Health and Health Sciences, led a study on the effectiveness of inexpensive face masks in Nepal. The study found that some air pollution passed right through the cloth material. Peltier also noted that wearing a cloth mask that is too tight can cause it to lose its filtering ability.

Additionally, a study published in the BMJ journal, Occupational and Environmental Medicine, found that most commercially available face masks, including internationally certified ones, do not provide adequate protection against particulate matter and black carbon due to poor facial fit. The filtration efficacy of the masks tested ranged from 0.26% to 29%, with average total inward leakage ranging from 3% to 68% in sedentary tests and 7% to 66% in active tests.

While N95 respirators are considered the gold standard, offering better filtration capabilities than simple face or surgical masks, they may not be accessible or affordable for everyone. Cloth masks are reusable and more readily available in many places with severe pollution. However, it is important to recognize that cloth masks may not provide sufficient protection against air pollution, and individuals should be cautious about relying solely on them for protection.

Surgical masks made out of paper performed well in tests

The efficacy of surgical masks in protecting against air pollution is a topic that has been widely studied. Surgical masks are designed to provide a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. They are made in different thicknesses and varying abilities to protect against contact with liquids.

Surgical masks are not a substitute for N95 respirators, which are designed to achieve a very close facial fit and block at least 95% of very small test particles. However, surgical masks made out of paper have performed well in tests. To ensure the purchase of a safe surgical mask, it is important to conduct some basic tests. Firstly, a safe mask should fit your face properly, covering your nose and mouth with an adjustable nose bridge and ear loops. A visual inspection of the mask ensures that it is 3-ply with a water-repellent coloured outer layer, a microfiltration middle layer, and a white absorbent inner layer.

Other tests for surgical masks include the breath test, which shows how effective the mask is at diffusing the breath, and the flame test, which detects the presence of polypropylene in the middle layer. It is also important to wear and store the mask correctly to avoid contamination. The safety of surgical masks is a concern for many, and it is only natural to wonder about the safety of masks made in different countries. The country of origin is not the only factor that determines the safety of a mask, and masks made in the UK are considered to be of high quality due to strict regulations.

While surgical masks may not be as effective as N95 respirators in blocking very small particles, they can still provide protection against larger particles and liquid droplets. They can also help reduce the exposure of respiratory secretions and saliva to others. In addition, studies have shown that head motions and positions do not significantly affect the performance of loose-fitting masks in filtering out nano-sized particles. This suggests that a simplified testing protocol for loose-fitting masks can provide a representative measure of particle filtration efficacy.

Masks must fit snugly to be effective

Facial masks are designed to protect against "particulate matter" (PM), which includes solid particles and liquid droplets in the air. PM 2.5 particles, in particular, are dangerous as they can penetrate deep into the lungs and impair lung function.

While facial masks can provide protection against particulate matter, it is important to note that their effectiveness depends largely on how well they fit. A study published in the BMJ journal, Occupational and Environmental Medicine, found that most commercially available face masks, including internationally certified ones, do not provide adequate protection against particulate matter due to poor facial fit. The study recommended that more attention be given to mask design to ensure a snug fit.

Richard Peltier, a professor at the University of Massachusetts, Amherst, in the Department of Public Health and Health Sciences, agrees that a snug fit is crucial. He led a study that tested several types of inexpensive face masks and found that cloth masks can provide protection if they fit snugly on the face. However, if they are pulled too tight, they lose their filtering ability.

Surgical masks made of paper performed well in Peltier's study, as they stuck to the wearer's wet mouth rather than fitting snugly on the face. The N95 respirator is another option that provides a very close facial fit. It is designed to block at least 95% of very small test particles and is considered the gold standard for protection against pollutants. However, N95 masks may not be available or affordable in many places with severe pollution.

To ensure the effectiveness of facial masks against pollution, it is important to choose a mask that fits snugly on the face. The Totobobo Mask, for example, has heat-molding abilities that allow users to customize the mask to their facial structure. While it may be more costly and less accessible, it provides a snug fit for better protection.

Masks do not protect against chemicals, gases, and vapours

While masks are designed to protect against particulate matter, they do not protect against chemicals, gases, and vapours. This is a significant concern, given that air pollution consists of complex reactions of chemicals, such as sulphur dioxide and nitrogen oxides, emitted from power plants, industries, and automobiles.

The limitations of masks in offering protection against air pollution are evident in the range of commercially-available face masks, including internationally certified ones, which do not adequately protect against particulate matter and black carbon due to poor facial fit. A study published in the BMJ journal, Occupational and Environmental Medicine, highlighted this issue, finding filtration efficacy ranging from 0.26% to 29% and average total inward leakage as high as 68% in active tests.

The N95 respirator is considered the gold standard, blocking at least 95% of very small test particles. However, these masks are often unavailable or too expensive in severely polluted areas. Additionally, they are not designed for children or people with facial hair, making it challenging to achieve a snug fit for full protection.

The effectiveness of masks is further compromised when they are reused. Masks trap humidity and heat, creating an environment conducive to viral, bacterial, and fungal contamination and infection. Therefore, unless masks come with disposable filters, they should be used only once and discarded if damaged or soiled.

In summary, while masks can provide some protection against particulate matter, they do not offer defence against chemicals, gases, and vapours present in air pollution. The limitations of mask design, availability, and affordability contribute to ongoing exposure to air pollution and the associated health risks.

Frequently asked questions