My opinion

By Dr. Deepak Gupta
Corresponding Author Dr. Deepak Gupta
Self, - United States of America
Submitting Author Dr. Deepak Gupta

masks, nasopharyngeal temperature, nasopharyngeal cells, narrow-band imaging, contact endoscopy

Gupta D. Personal journey of in-mask nasopharyngeal temperature: Is it time to investigate whether one-year of pandemic mitigation measures has induced nasopharyngeal cellular changes detectable by narrow-band imaging and/or contact endoscopy?. WebmedCentral OTORHINOLARYNGOLOGY 2021;12(4):WMC005700

This is an open-access article distributed under the terms of the Creative Commons Attribution License(CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submitted on: 01 Apr 2021 11:35:39 PM GMT
Published on: 06 Apr 2021 03:19:59 AM GMT

My opinion

Unlike rare personalities who are able to do what they say [1], I am just like any other biological/non-biological algorithm-bound living thing who despite being physically free [2], will always be a prisoner of my thoughts. I used to sympathize with those who can't or won't wear masks during pandemic. Now I envy them because it is becoming difficult for me to let go my masks and take them off despite vaccination. I am chained to my thought of masks' potential therapeutic role secondary to masks creating non-physiological hot and humid micro-environments. For the last one year or so, I have been feeling that my masks are not just passive bystanders by preventing SARS-CoV-2 infection in me but actively fighting against SARS-CoV-2 by heated humidity in my breathing environment. Moreover, besides always masked when at work or if out-of-home, indoor temperatures at my home have gotten dialed up from pre-pandemic 68-70 F to 77-78 F since the pandemic to avoid normal vasomotor physiology [3-4] of nose misrepresenting itself as pandemic era pathology. Now the questions arise how, when, and why I may have to let go my hot and humid micro-environments in due course of time very soon [5].

The question of how is very simple. I will have to change as per updated guidelines of experts and authorities to take my masks off [6]. The question of when is simple too. Once I have mustered enough courage, I will set my nose free from the shackles of "therapeutic" masks [7]. The question of why is a little complicated as it is mostly unanswered why I started wearing masks despite not liking them and why I have to stop wearing them despite being afraid to take them off. Some explorative questions may help in allaying my fear to take them off although my thought about their therapeutic role may remain permanently imprinted on to my core. 

Should the world explore whether nose-mouth inhalation-exhalation pattern might have been better than mouth-mouth inhalation-exhalation pattern under the masks to keep nasopharynx cooler with maybe brain cooler too even though it might have been difficult-to-follow tedious, exhausting and noisy nose-mouth inhalation-exhalation pattern day-in-day-out under the flow-resistive masks [8-12] which induce breathing resistance considering that hotter nasopharynx with mouth-mouth inhalation-exhalation pattern might have been better for potential "therapeutic" role of masks?  

Should the world explore whether in-mask hot and humid micro-environments with mouth-mouth inhalation-exhalation pattern may have correspondingly created hot and humid nasal and nasopharyngeal cavities which being non-physiological for those cavities may have the potential to induce cellular changes therein mimicking the disuse atrophy or other patterns observed in these cavities among the laryngectomy patients [13] who have almost no air current flowing through their noses?

Should the world explore whether non-physiological hot and humid nasal and nasopharyngeal environments may have forced them to go into overdrive as heat-exchangers with reversal of their role from warming and humidifying the colder and drier ambient inhalations to potentially cooling and dehumidifying the hotter and wetter in-mask inhalations considering that absolute/specific humidity under the masks and correspondingly within nasal and nasopharyngeal cavities increase to discomforting supra-normal levels thus making the physiologically present 100%-saturated relative humidity within the nasopharynx pathologically irrelevant [14-15]? 

Should the world explore whether non-physiological trapped heat and humidity within the masks and correspondingly within nasal and nasopharyngeal cavities may lead envisioning the long term effects as cellular changes therein as similar to hot and humid geographical climate related distribution of cellular changes in the nasopharynx especially when there is a discordance between the nasal and nasopharyngeal anatomy that had evolved to survive in cold-dry climate and the seasons-pandemics which are forcing those evolved populations to live in hot-humid ambient or in-mask climate [16-18]?

Should the world explore whether hot and humid micro-environment may erroneously feel "soothing" to the oral cavity and its swollen structures like tonsils, if any, especially if mouth-mouth inhalation-exhalation pattern may appear warming but dehumidifying the oral mucosa and the swollen structures therein when mouth tries but fails miserably to mimic nose's heat-exchanging and humidity-holding mechanisms as demonstrated by collection of exhaled breath condensate during non-humidity holding oral breathing when compared to humidity-holding nasal breathing [19-27]?

Should the world explore whether hot and humid nasopharyngeal cavities of healthcare workers wearing N95 respirators day-in-day-out during pandemic need to be formally investigated for cellular changes by narrow-band imaging and/or contact endoscopy [28-30] to see if there are any long term cellular consequences of mask-wearing on their nasopharynx because it is not clear whether it is the calculated changes in diet to avoid high-salty dishes or it is the eased provisions for controlled air-conditioning providing cooler and drier living conditions which have brought down the incidence of nasopharyngeal cellular changes in populations who had been at-risk for nasopharyngeal oncogeny [31-39]? 

The bottom line is that there is so much which the world needs to explore and document. I am just sharing the changes in my nasopharyngeal temperature. Figure 1 demonstrates my right-sided nasopharyngeal temperature having a roller coaster ride under masks worn in various combinations with head coverings and face shields while a second temperature probe just outside my left nostril keeping a track of the temperature of air being inhaled while wearing or not wearing mask/head covering/face shield.

Vertical Zones within Figure 1 represent what the combination of mask/head covering/face shield was:

Vertical Zone A: No mask/head covering/face shield

Vertical Zone B: Bouffant cap

Vertical Zone C: Bouffant cap + Simple mask

Vertical Zone D: Bouffant cap + N95 respirator

Vertical Zone E: Bouffant cap + N95 respirator + Simple mask

Vertical Zone F: Bouffant cap + N95 respirator + Simple mask + Face shield

Vertical Zone G: No mask/head covering/face shield

Vertical Zone H: Thick woolen hat

Vertical Zone I: Transitioning period

Vertical Zone J: Bouffant cap + Cotton mask + Bandana + Surgical mask + Face shield

Vertical Zone K: Bouffant cap + N95 respirator + Bandana + Surgical mask + Face shield

Vertical Zone L: No mask/head covering/face shield

Vertical Zone M: Thick woolen hat

During vertical zones A-H, only nasal breathing was happening. During vertical zones I-M, only oral breathing was happening.

Few interesting observations were unraveled. Thick woolen hat (vertical zones H and M in Figure 1) and not bouffant cap (vertical zone B in Figure 1) somewhat increased nasopharyngeal temperatures. Irrespective of mask/head covering/face shield, nasopharyngeal temperatures were higher during oral breathing (vertical zones I-M in Figure 1) as compared to during nasal breathing (vertical zones A-H in Figure 1), most likely due to the lost cooling effect of moving air which was not moving across the nasopharynx during oral breathing. Simultaneously, irrespective of mask/head covering/face shield, oral breathing related exhaled breaths seemed to warm the ambient air environment to be inhaled as demonstrated by higher temperatures outside left nostril during oral breathing (vertical zones I-M in Figure 1) as compared to during nasal breathing (vertical zones A-H in Figure 1); this exaggerated warming induced by exhaled breaths exiting mouth seemed to be secondary to the absence of cooling effect of nose on them during oral breathing because the cooling effect of nose during nasal breathing can even try to maintain nasopharyngeal temperatures below in-mask environment temperatures (vertical zones E-F in Figure 1) which can overshoot due to the trapped heat under the masks with/without head covering and/or face shield. It will be interesting to see in future if nasopharyngeal temperatures remain higher and/or increase further when duration of nasal and/or oral breathing is prolonged irrespective of mask/head covering/face shield thereby simulating healthcare workers wearing mask/head covering/face shield for many work-hours per workday because doffing the masks (vertical zones G and L in Figure 1) decreases nasopharyngeal temperatures rapidly although baseline nasopharyngeal temperatures may remain higher during oral breathing (vertical zone L in Figure 1) as compared to during nasal breathing (vertical zone G in Figure 1). Although, during this short duration ~1-hour graphing of nasopharyngeal temperatures at 1-minute intervals in Figure 1 the fluctuations with each breath were not recorded as similar to septal mucosal surface temperature recorded by others [40-41], it appeared that nasopharyngeal temperatures on the temperature monitor screen were fluctuating more often over a range with each breath in the absence of masks but not in the presence of masks making the case for exhaled breaths’ heat trapped under masks reaching an equilibrium under masks thus potentially preventing the nasopharyngeal temperatures to fluctuate with each breath under masks. Similar thoughts can be investigated to make or break the case for more fluctuations in windy cold outdoor environments as compared to controlled temperature indoor climates or during rapid shallow breathing as compared to slow deep breathing (nasopharyngeal temperatures in Figure 1 were graphed with slow deep breathing in indoor environment controlled at 77 F temperature).

Although heat/humidity reducing masks with exhalation valves are no longer recommended to use and heat/humidity adsorbent/absorbent material-based non-valved masks are yet to be developed, the heat trapped under masks is surely raising nasopharyngeal temperature, more so during oral breathing, making the case for a heated microenvironment getting created within nasopharynx while wearing masks with or without wearing head covering and face shield concurrently. Herein, Figure 2 of ~2-hours graphing left nasopharyngeal and right nostril temperature combination demonstrates that nose-nose inhalation-exhalation pattern (rectangular curve A in Figure 2) and nose-mouth inhalation-exhalation pattern (rectangular curve C in Figure 2) ends up with nose reversing its warming the nasal inhalation role during cooler ambient climate to cooling the nasal inhalation role during warmer in-mask climate thus preventing too much rise in nasopharyngeal temperature while mouth-mouth inhalation-exhalation pattern (rectangular curve D in Figure 2) much more than mouth-nose inhalation-exhalation pattern (rectangular curve B in Figure 2) turns up the heat within the nasopharynx in the absence of heat-exchanging nasal inhalations. Interestingly for me, nose-nose inhalation-exhalation pattern has been natural during ambient living condition and mouth-mouth inhalation-exhalation pattern has been essential during in-mask living condition while nose-mouth inhalation-exhalation pattern has been exhausting during in-mask living condition despite being the coolest for nasopharynx and mouth-nose inhalation-exhalation pattern has been unnatural during any living condition.

It will be only time and future biomedical research that may prove or disprove if heated microenvironment in nasopharynx is going to be detrimental to cold viruses like SARS-CoV-2 [42] by inactivating them thus imparting masks a therapeutic role therein because, although it remains to be seen if 100% relative humidity constantly maintained within nasopharynx physiologically [15] means that absolute humidity during hotter nasopharyngeal temperatures will be more than during colder nasopharyngeal temperatures or whether nasal and nasopharyngeal cavities are equally effective in cooling the hotter ambient air as they are in heating the colder ambient air, warm mist inhalation (and NOT cool mist inhalation) that may raise nasopharyngeal temperature to higher level even during nasal breathing (Figure 3 of ~30-minutes graphing left nasopharyngeal and right nostril temperature combination) may not be always possible and certainly not feasible during many work-hours per workday and mouth breathing may not be always feasible or advisable over nasal breathing [43-47]. Hereafter, it will be very futuristic to investigate if there will be a trade off by nasopharyngeal heat inactivating viruses for now vs. nasopharyngeal heat activating oncogeny for later or a win-win by nasopharyngeal heat not only inactivating viruses but also oncogeny as well [48-53].

Fig 1:






Fig 2: 



Fig 3: 


Summarily, while this avenue of heated nasopharynx under masks needs future investigations to validate or refute my personal observations before this avenue’s generalization and applicability to explore potentially therapeutic role of heated nasopharyngeal microenvironment getting created under masks to make or break the case for masks serving as non-pharmacological therapeutic interventions [54] in the short term against cold viruses like SARS-CoV-2, it should NOT be overlooked that nasopharyngeal cells may have to be concurrently investigated for demonstrating the long term effects, if any, of pandemic mitigation measures which have warranted long duration use of non-physiological masks with or without head covering/face shield especially among the healthcare workers at the frontline.      


  1. I Am the Master of My Fate. https://www.ncbi.nlm.nih .gov/pmc/articles/PMC3944843/pdf/AC-2003.pdf
  2. Are humans the only species to imprison each other for doing wrong? http s://
  3. Why does your nose run when it's cold? https://medic
  4. Vasomotor Rhinitis.
  5. Pandemic isn't over, but there's hope — and confusion. sion/ar-BB1eVlLf
  6. When You’ve Been Fully Vaccinated. How to Protect Yourself and Others. coronavirus/2019-ncov/vaccines/fully-vaccinated.html
  7. “Therapeutic” facemasks. es/PMC7236693/
  8. Objective Assessment of Increase in Breathing Resistance of N95 Respirators on Human Subjects. le/55/8/917/265317
  9. Inspiratory flow rates during hard work when breathing through different respirator inhalation and exhalation resistances.
  10. Oronasal partitioning of ventilation during exercise in humans.
  11. Breathing route and ventilatory responses to inspiratory resistive loading in humans.
  12. Study of respirator effect on nasal-oral flow partition.
  13. Long-Term Histologic Changes in Nasal Mucosa after Total Laryngectomy. 10/137128/
  14. Absolute humidity and the human nose: A reanalysis of climate zones and their influence on nasal form and function. i/abs/10.1002/ajpa.23032
  15. A technique to measure the ability of the human nose to warm and humidify air. https://journals.physiolo
  16. Whence the Chinese? news.php?unit=20,20,29,35,35,45&post=25930
  17. [The mongoloid nose]
  18. Climate-related variation of the human nasal cavity.
  19. Mouth breathing can affect sleep, tonsils. conditions/mouth-breathing-can-affect-sleep-tonsils/article572716/
  20. Recurrent tonsillitis and parental perceptions of tonsillectomy during the COVID-19 pandemic. es/PMC7583584/
  21. Enlarged tonsils and adenoids: Overview.
  22. Breathe Through Your Nose (Even While Wearing A Mask). https://www.bradfordfamilyden
  23. The relationship between water vapour saturation of inhaled air and nasal patency.
  24. Humidity and temperature profile in the nasal cavity.
  25. Air Temp, Moisture Determine How Stuffy Nose Feels. https://www.medpagetoda
  26. Surprising Facts About Your Nose. https://health.clevelandclinic.or g/7-surprising-facts-nose/
  27. Increased net water loss by oral compared to nasal expiration in healthy subjects.
  28. Narrow-Band Imaging: A Novel Screening Tool for Early Nasopharyngeal Carcinoma. https://jamanetwork.c om/journals/jamaotolaryngology/fullarticle/1106976  
  29. Contact Endoscopy as a Novel Technique in the Detection and Diagnosis of Mucosal Lesions in the Head and Neck: A Brief Review. 302/
  30. Surveillance tools for detection of recurrent nasopharyngeal carcinoma: An evidence-based review and recommendations. https://www.sciencedirect .com/science/article/pii/S2095881120301736
  31. Hydrogen donors and acceptors and basic amino acids jointly contribute to carcinogenesis.
  32. Why nasopharyngeal cancer is prevalent in hot and humid areas.
  33. How Does Specific Humidity Vary Globally and Seasonally? https://geogr
  35. Evaluation of non-viral risk factors for nasopharyngeal carcinoma in a high-risk population of Southern China. es/PMC4406046/
  36. Nasopharyngeal carcinoma in the Northeastern states of India. es/PMC4013339/
  37. Risk Factors for Nasopharyngeal Cancer.
  38. Nasopharyngeal Carcinoma (NPC) Risk Factors: A Systematic Review and Meta-Analysis of the Association with Lifestyle, Diets, Socioeconomic and Sociodemographic in Asian Region.
  39. Non-viral environmental risk factors for nasopharyngeal carcinoma: A systematic review. https://www.sciencedi
  40. Nasal mucosal temperature during respiration. https://onlinelibrar
  41. A Numerical Simulation of Intranasal Air Temperature During Inspiration. https://onlinelibrar
  42. Disparate temperature-dependent virus – host dynamics for SARS-CoV-2 and SARS-CoV in the human respiratory epithelium. 0.1101/2020.04.27.062315v2
  43. The right way to breathe during the coronavirus pandemic. h ttps://
  44. Study: Nose appears to be better at spreading COVID-19 than mouth. local/study-nose-appears-to-be-better-at-spreading-covid-19-than-mouth/article_ffac5a53-f85f-5449-ae 80-be6eae151d22.html
  45. Could nasal nitric oxide help to mitigate the severity of COVID-19? es/PMC7200356/
  46. Nasal Breathing: Your Secret Weapon Against COVID-19? https://gall
  47. Can Nasal Breathing Help Reduce Your Risk of COVID-19? https://deci
  48. Kangri cancer.
  49. Mini tumors predict how cancer responds to heat treatment. eat-treatment.aspx 
  50. Cold environment makes cancer grow and spread faster. 9266
  51. Chilly temperatures help cancers grow. https://theconversati
  52. Update: Turning the Heat on Cancer. es/PMC2987268/
  53. Proteotoxic stress of cancer: implication of the heat-shock response in oncogenesis. es/PMC3431153/
  54. Does mask use affect the quantitative severe acute respiratory syndrome coronavirus 2 load in the nasopharynx? es/PMC7511154/

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