Addition of PAC with HEPA filter may prevent COVID-19 spread in dental clinics: Study

Written By : Dr. Nandita Mohan |Medically Reviewed By : Dr. Kamal Kant Kohli Published On 2021-02-03T20:36:55+05:30 | Updated On 4 Feb 2021 1:32 PM IST

Researchers from the Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA have said that aerosol accumulation may occur in dental treatment rooms with poor ventilation. Addition of portable air cleaner (PAC) with a HEPA filter will significantly reduce the aerosol accumulation and accelerated aerosol removal, as documented in the recent study published in the Journal of Dentistry.

Yan-Fang Ren and colleagues, therefore conducted the study to evaluate the mechanical ventilation rates of dental treatment rooms and assess the effectiveness of aerosol removal by mechanical ventilation and a portable air cleaner (PAC) with a high-efficiency particulate air (HEPA) filter.

Volumetric airflow was measured to assess air change rate per hour by ventilation (ACHvent). Equivalent ventilation provided by the PAC (ACHpac) was calculated based on its clean air delivery rate. Concentrations of 0.3, 0.5, and 1.0 μm aerosol particles were measured in 10 dental treatment rooms with various ventilation rates at baseline, after 5-min of incense burn, and after 30-min of observation with and without the PAC or ventilation system in operation.

Velocities of aerosol removal were assessed by concentration decay constants for the 0.3 μm particles with ventilation alone (Kn) and with ventilation and PAC (Kn+pac), and by times needed to reach 95 % and 100 % removal of accumulated aerosol particles.

It was observed that –

a. ACHvent varied from 3 to 45. Kn and Kn+pac were correlated with ACHvent (r = 0.90) and combined ACHtotal (r = 0.81), respectively.

b. Accumulated aerosol particles could not be removed by ventilation alone within 30-min in rooms with ACHvent<15.

c. PAC reduced aerosol accumulation and accelerated aerosol removal, and accumulated aerosols could be completely removed in 4 to 12-min by ventilation combined with PAC.

d. Effectiveness of the PAC was especially prominent in rooms with poor ventilation.

e. Added benefit of PAC in aerosol removal was inversely correlated with ACHvent.

Hence, the authors concluded that the "addition of PAC with a HEPA filter improves aerosol removal in rooms with low ventilation rates."

portable air cleanerHEPA filteraerosol exposuresdental treatment roomsJournal of Dentistry

Source : Journal of Dentistry

Dr. Nandita Mohan

BDS, MDS( Pedodontics and Preventive Dentistry)

Dr. Nandita Mohan is a practicing pediatric dentist with more than 5 years of clinical work experience. Along with this, she is equally interested in keeping herself up to date about the latest developments in the field of medicine and dentistry which is the driving force for her to be in association with Medical Dialogues. She also has her name attached with many publications; both national and international. She has pursued her BDS from Rajiv Gandhi University of Health Sciences, Bangalore and later went to enter her dream specialty (MDS) in the Department of Pedodontics and Preventive Dentistry from Pt. B.D. Sharma University of Health Sciences. Through all the years of experience, her core interest in learning something new has never stopped. She can be contacted at editorial@medicaldialogues.in. Contact no. 011-43720751

Dr. Kamal Kant Kohli

Dr Kamal Kant Kohli-MBBS, DTCD- a chest specialist with more than 30 years of practice and a flair for writing clinical articles, Dr Kamal Kant Kohli joined Medical Dialogues as a Chief Editor of Medical News. Besides writing articles, as an editor, he proofreads and verifies all the medical content published on Medical Dialogues including those coming from journals, studies,medical conferences,guidelines etc. Email: drkohli@medicaldialogues.in. Contact no. 011-43720751