Every Breath We Take: Air Pollution and Masks

By: Dynasti deGouville

With COVID-19 restrictions being lifted all over the country, mask mandates will soon be a thing of the past. As of April 10th, five states have lifted all mask mandates at both the state and local levels. The termination of mask mandates may lead to a surge in coronavirus cases if the general public is not vaccinated.[1] Additionally, masks have been used to protect against other respiratory infections caused by air pollution. Could the end of mask mandates affect respiratory and cardiovascular illness frequency due to air pollution? 

A primary route of transmission of COVID-19 is via small respiratory droplets, and is known to be transmissible from presymptomatic and asymptomatic individuals. The prevalence of evidence indicates that wearing a mask reduces transmission of infected droplets in both laboratory and clinical contexts. Public mask wearing is most effective at stopping spread of the virus when compliance is high.[1] Thus, every state has implemented mask mandates in place, either on the state or local level. However, with vaccine rollout and mask mandates loosening as a result, many will soon begin to put down the mask and return to normalcy. 

One of our era’s greatest scourges is air pollution, on account not only of its impact on climate change but also its impact on public and individual health due to increasing morbidity and mortality.  One major air pollutant, particulate matter (PM), penetrates the respiratory system via inhalation and can lead to  respiratory and cardiovascular diseases, reproductive and central nervous system dysfunctions, and cancer. Particulate matter is the term for a mixture of solid particles and liquid droplets found in the air including particles such as dust, soot, or smoke in the atmosphere. 

Most particulate matter is emitted from construction sites, unpaved roads, wildfires or power plants, industries, and automobiles. Particulate matter contains microscopic solids or liquid droplets that are so small that they can be inhaled and cause serious health problems. Some particles less than 10 micrometers in diameter can penetrate deep into your lungs. In some cases, it may even be found in the bloodstream. Particles less than 2.5 micrometers in diameter, also known as fine particles or PM_2.5, pose the greatest risk to respiratory health. In the United Kingdom, the risks of air pollution to health were thought to have been brought under control by the Clean Air Acts of the 1950s and 1960s. However, the situation of air pollution in the UK has now deteriorated to a point where it is contributing to 40,000 excess deaths each year.[2] In 2019, the United States estimated that over 60,000 deaths were attributed to air pollution. 

Many citizens of East Asian countries, such as Beijing, have been wearing face masks to protect themselves against thickening smog. One study conducted in 2018 found that many commercially available face masks may not provide adequate protection, primarily due to poor facial fit.[3] While studies in China have found that wearing face masks can have positive impacts on short-term health outcomes such as blood pressure and heart rate variability, it is unclear what level of exposure reduction was associated with these impacts, given that only particulate concentrations were measured.[4] The filtration efficiency of a mask depends on particle size, charge, concentration and flow rate through the filter material. In practice, the contaminant may pass through the face filter, bypassing small gaps between the edge of the mask and the face, so-called ‘edge-seal leakage’. The extent of leakage depends on factors such as the size and shape of the face, facial hair, the respirator design, and mask fit. 

Disposable masks sold for use in the workplace are often tested and comply with international and national standards. However, those sold publicly for protection against air pollution often do not comply with standards and most likely do not provide adequate protection. One study investigated the filtration efficiency of mask filter material complying with the N95 criteria (filtering ≥95% of the particles). They found that between <0.5% and 4.3% of elemental carbon passed through the filters. Several mask materials allowed <5% of elemental Carbon to pass through the material. A study of the filtration efficiency of masks mounted on a mannequin head with a mask sealed to the head found penetration of elemental Carbon between 11% and 15% for FFP2 masks and 13%—24% for FFP3 masks.[5] Thus, the issue with masks is not an issue with filtration—— masks are often efficient filters—— but rather an issue with fitting. Allowing gaps between a person’s face and the mask allows space for PM to enter the body. 

East Asians have been masking up regularly for decades with the practice gaining additional traction during the 2003 SARS outbreak and subsequent flu seasons. They see it as socially responsible and respectful not only to others but also to themselves. It protects them from potential viral infections, but given the intense rise in smog hovering over highly populated cities, the masks have also become a necessity as a preventative measure against air pollution among other harmful vessels in highly populated cities.

So, should we continue wearing masks to combat air pollution? Not necessarily. 

Reports show that particulate matter has been reduced in most locations by significant amounts, oftentimes by about 50 percent over the past 30 years. But there is a problem with pollutants that are very difficult to control because of various chemical processes that occur in the atmosphere. While it is true that some masks protect against particulate matter, they are often ill-fitting  and do not truly provide adequate protection. To combat respiratory and cardiovascular illnesses caused by air pollution, efforts should instead be focused on environmental reform on the legislative level and less on wearing masks. It is more productive–necessary even–to lobby for greater environmental regulation. Through environmental protections, particulate matter concentrations will decrease and lead to cleaner and safer air for everybody. 

References 

[1]Howard, J., Huang, A., Li, Z., Tufekci, Z., Zdimal, V. (2021). An evidence review of face masks against COVID-19. PNAS, 118(4). https://doi.org/10.1073/pnas.2014564118

[2]Holgate S. T. (2017). ‘Every breath we take: the lifelong impact of air pollution’ – a call for action. Clinical medicine (London, England), 17(1), 8—12. https://doi.org/10.7861/clinmedicine

[3]Cherrie, J. W., Apsley, A., Cowie, H., Steinle, S., Mueller, W., Lin, C., Horwell, C. J., Sleeuwenhoek, A., & Loh, M. (2018). Effectiveness of face masks used to protect Beijing residents against particulate air pollution. Occupational and environmental medicine, 75(6), 446—452. https://doi.org/10.1136/oemed-2017-104765

[4]Langrish, J. P., Mills, N. L., Chan, J. K., Leseman, D. L., Aitken, R. J., Fokkens, P. H., Cassee, F. R., Li, J., Donaldson, K., Newby, D. E., & Jiang, L. (2009). Beneficial cardiovascular effects of reducing exposure to particulate air pollution with a simple facemask. Particle and fibre toxicology, 6 (8). https://doi.org/10.1186/1743-8977-6-8

[5]Penconeck, A., Drazyk, P., Moskal, A. (2013). Penetration of Diesel Exhaust Particles Through Commercially Available Dust Half Masks. The Annals of Occupational Hygiene, 57(3), 360-373. https://doi.org/10.1093/annhyg/mes074