Dental Tribune India

Control “humidity” inside your clinic to minimize COVID 19 spread- Mansoor Ali, air quality expert

By Rajeev Chitguppi and Mayur Khairnar
May 11, 2020

Mansoor Ali, a research analyst and veteran in the air treatment products industry, speaks about the role of relative humidity in controlling the spread of coronavirus. He is the founder of AMFAH, whose efforts have been recognised by the Marico Foundation for innovations in tackling the Coronavirus outbreak. Currently, his team is working closely with the Maharashtra health ministry team to set guidelines for various industries post lockdown period.

1. What should dentists know about the risk of droplet spread and airborne spread that can happen in their dental clinics? 

It may not look like it, but the modern dentistry environment is a fertile environment for the spread of the coronavirus through droplets and airborne spread. Dentists work on a minute, intimate level with their patients - working with dental and surgical instruments close to the mouths of their patients. There are face-to-face communication, sharp instruments and routine coughing and spitting.

The patients in question, deposit mucus and fluids in the form of saliva, blood and other dental debris in routine dental work. These spread over all nearby surfaces such as the floor, operatory surfaces, dental instruments, masks and all.

Wearing surgical masks can protect the mouth and nose from droplet spread, but it does not completely protect from the risk of inhaling the airborne spread of the coronavirus.

Depending on the indoor air quality and humidity, the virus can remain suspended in the air on droplets smaller than 5 micrometres (aerosols) for 30 minutes, before it drifts down and settles on surfaces.

2. What about the acts of talking, sneezing, coughing and spitting that can happen inside a dental clinic? How far can the droplets spread and for how long they can remain in the clinic air? 

The coronavirus does not spread far and settles quickly on all available surfaces. So, if we consider a normal patient-doctor consultation, normal acts of talking, sneezing, coughing and spitting will spread the viral strains onto the examination chair, floor, seating area, instruments, desks, walls and all indoor surfaces.


3. For how long will the virus droplets remain on various surfaces after they settle down? 

Depending on the indoor air quality levels, air circulation and humidity levels, the viral strains can remain for several hours to days on all surfaces, if they are not vigorously cleaned, disinfected and sanitised on a regular basis.


4. What does your research say about the effect of temperature on the novel coronavirus and how can we optimise the temperature inside the dental clinics? 

According to the current research, a temperature setting between 24-27 degrees and humidity levels between 50 to 60 RH will be an ideal environment for dental clinics, alongside proper sanitisation measures.


5. Dry air vs Humidity: Which one is detrimental to the survival of the virus? What role does humidity play on the survival of the virus?

It’s neither about dry air or hot, humid conditions. It’s about maintaining a balance - one that allows someone to maintain their immunity levels and not fall prey to the disease.

A 2018 study in the Applied and Environment Microbiology had found that coronaviruses thrived whenever relative humidity levels either fell below 60% (became too dry) or exceeded 85% (became too humid). The window between 60-85% saw a drop in their effectiveness in spreading and remaining on surfaces. These resets are applicable to cold countries with higher humidity. For tropical warmer countries like India Singapore, Thailand, etc.. RH humidity just be maintained to 40-60 % RH

Read more from Mansoor Ali: An air quality expert has come up with an indoor environment formula that can help people stay safe from the dreaded COVID-19 pandemic.


6. What does your research say about how best dentists can optimize the humidity inside the dental clinics? 

Ensure that there is a dehumidifier within your dental clinic. If you cannot account for that, ensure there is optimum ventilation and sources for optimum indoor humidity - indoor plants, a discreet bowl of water inside an AC room and frequent airing of your dental clinic.

Considering India as a tropical country, we should stick to humidity settings of 40-60% RH & next 3-4 months are peak of summer season & monsoon approaching, we are already witnessing higher humidity adding to the spread, we need to install dehumidifiers with air filters features.

Read more from Mansoor Ali: It is time to think in terms of humidity, temperature and air quality (indoors as well).

7. What should dentists know about ventilation inside the clinic- use of fans, AC, dehumidifiers inside a clinic?

Optimum ventilation is a necessity in all indoor and closed spaces, to ensure that the environment remains breathable, fresh and clean. If you’re worried about using fans or ACs and how they may allow the virus to spread faster, ensure aggressive sanitisation and disinfection of your offices.

In fact, we encourage larger dental clinics to consider medical-grade HEPA filters and ultraviolet rays in their ventilation systems, which remove a larger set of pathogens and microorganisms from the air.

If you feel that one of your patients is exhibiting signs of the coronavirus, shut down the office and opt for full scale sanitation - it will take three days, but it is a cautious way to ensure that you do not catch the virus, or lead to transmission to others.

Read more from Mansoor Ali: Cooling for hotels in Covid-19 India: Essential Do’s and Don’ts for ACs

8. How is the rainy season going to influence the survival of this virus? 

All research on the new strain of the novel coronavirus (COVID-19) is still in a fairly nascent stage, so it is hard to conclude anything about how the virus may fare during the rainy season. In fact, many assumptions about the virus dying due to summers have also proven to be false.

I would say that it is fairly early to consider the impact of the rainy season on the virus.


9. What recommendations have you made to the govt for containing the virus spread inside the hospitals and which ones among those have been implemented till now?

We’ve recommended large-scale plans and strategies to ensure temperature monitoring, humidity control and optimum indoor air quality levels. We’ve also asked for a segmented people movement to restart the economy and ensure social distancing.

We’ve shared our findings with both the Maharashtra government as well as the central government. However, it is very early to talk about implementation, considering that both governments are fighting against the COVID-19 outbreak on a massive scale.


10. What would be your top three recommendations to the dentists on the measures they can take to control the virus spread inside the clinic? 

I would recommend these three factors to all dentists -

  1. Periodic sanitisation of the clinic, dental chairs and indoor surfaces.
  2. Temperature monitoring for all incoming patients and mandatory shutdown + sanitation in case there is a suspected positive patient.
  3. Ensuring a golden balance of indoor air quality, room temperature and humidity inside the clinic.



Mansoor Ali, a research analyst and veteran in the air treatment products industry, speaks about the role of relative humidity in controlling the spread of coronavirus. He is the founder of AMFAH, which was the earliest, as early as March 26th 2020, to present their research data to the Health Ministry of Maharashtra. AMFAH's efforts have been recognised by the Marico Foundation for innovations to tackle the Coronavirus outbreak. His project is one of the few shortlisted innovations for the Marico Foundation's coveted honour. Currently, his team is working closely with the Maharashtra health ministry team to set guidelines for various industries post lockdown period. They are also working on a CSR campaign protecting the corona leadership from healthcare to administration and key police officials in Mumbai.



Dr Mayur Khairnar (MDS) is a periodontist and implantologist specializing in
immediate loading and full mouth implant rehabilitation.
He maintains his private practice in Andheri (Mumbai).



  • Very valuable observations and recommendations for dental operatory. Hope we are able to implement in toto and ease out the complexities of present situation. Thanks for sharing.

  • Anuradha Sunil says:

    What is the best and most affordable sanitiser for dental chairs and surfaces?


    Good Morning

    I wonder if dr. Can Mansoor Ali indicate the specifications, type and brand of HEPA filter, air conditioner and hood to buy?

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