Syracuse, NY, Aug. 31, 2020 (GLOBE NEWSWIRE) --
The coronavirus has drastically changed the way people work, learn and gather together. Classes are remote for many students, offices are closed and workers operate out of their homes – all in an effort to slow the spread of this fast-moving and dangerous virus.
The coronavirus disease is a respiratory illness that can spread from person to person, typically through respiratory droplets from coughing, sneezing, or talking. One salvation for many people stuck at home is being outside and enjoying the warmer weather. In the open air, coronavirus particles disperse more quickly than they do inside.
But what happens when the colder weather hits and it is harder to be outside? When you're indoors, you're more likely to inhale these droplets from an infected person. Poor building ventilation can cause droplets to hang in the air for a longer period of time, adding to the potential for infection.
So what can be done? Syracuse University Professor Jianshun "Jensen" Zhang says that one strategy is found in air filters, air purifiers and using a three-step plan to improve indoor air quality, (IAQ).
Zhang's plan is detailed in a recent editorial published in the journal Science and Technology for the Built Environment called "Integrating IAQ control strategies to reduce the risk of asymptomatic SARS CoV-2 infections in classrooms and open-plan offices."
Dr. Zhang, a professor in the Department of Mechanical and Aerospace Engineering at Syracuse University and Director of the Building Energy and Environmental Systems Laboratory, writes that source control, ventilation and air cleaning - and combinations of all three – are important tools in preventing the spread of COVID within indoor spaces.
Here's a look at his three-step plan:
Source Control
Source control is the first and most important among all IAQ strategies, says Zhang. For preventing the spread of the coronavirus, that means detecting, tracking, and isolating infected persons; and preventing transmission from asymptomatic virus carriers.
"The latter is more challenging in open space office or classroom settings in which air is typically well mixed," Zhang says. "To reduce the number of virus-containing aerosols emitted to the space from any possible virus carriers present, universal face masking, as well as hand sanitizing before entering the space is essential."
Ventilation
The next step in air quality is ventilation with a focus on supplying enough clean outdoor air to rooms and offices which would help dilute coronavirus particles in the air.
"Mechanically ventilated classrooms and offices typically have about 20 percent of their air supplied from outdoors, and the rest is recirculated air. This is done to save heating and cooling energy," Zhang says. "To reduce the risk of the coronavirus infection, the outdoor ventilation rate should be increased to the maximum operational capacity of the building ventilation system.”
He says that any recirculated air needs to be filtered with HEPA filters or MERV-14 filters, to minimize cross-contamination.
Zhang says that proper air distribution is essential for making sure the filtered air is reaching the people where they are. He says that most classrooms and offices deliver air through vents at or close to the ceiling level. Zhang recommends that vents should be close to the floor level, allowing the filtered air to spread toward the occupants. The exhaled air then move upwards for it it to be exhausted at, or close to, the ceiling level.
(VIDEO: Prof. Zhang explains his concept for removing COVID containing aerosols from indoor air in offices, classrooms and homes—here’s the link: https://vimeo.com/452228910)
Air cleaning
The final step is air cleaning. This can be as broad as filtering the air in an entire building using HEPA or MERV-14 filters or as personal as individuals wearing masks within a room.
Zhang says that stand-alone air cleaners equipped with HEPA filters can be a supplemental measure to coronavirus particles in the air. Zhang says this can be a cost-effective supplementary measure for rooms with limited airflow.
More information:
Zhang will be discussing these strategies during a panel discussion organized by Syracuse University’s Center of Excellence in Energy and Environmental Systems. The discussion Air Purifiers & Airflows: Minimizing COVID-19 Risk in Classrooms, on Tuesday, Sept. 1 from 11 a.m. to noon, will focus on classrooms and how air can be replaced or purified to help protect students and teachers.
Further research:
A newly-released research brief by Syracuse University Professor Eric Schiff, interim executive director of the SyracuseCoE, uses indoor air quality measures such as masking and ventilation to calculate the risk of contracting the virus within a classroom and with a superspreader present.
About
Zhang is Professor and Director of Building Energy and Environmental Systems Laboratory, Department of Mechanical and Aerospace Engineering at Syracuse University (SU), New York, USA, and a Visiting Professor and Chief Researcher of the School of Architecture and Urban Planning at Nanjing University, China. He is a Faculty Fellow at SyracuseCoE,
Zhang is a co-leader of the Syracuse University research cluster in Energy and Environment that promotes and coordinates multi-disciplinary research on the campus. He is an expert in room air and contaminant distribution, material emissions, air purification, building enclosure performance, and combined heat, air, moisture and pollutant simulations (CHAMPS) for integrative design and intelligent controls of buildings.
Much of this work takes place in the Total Indoor Environmental Quality Laboratory (TIEQ Lab) at SyracuseCoE. The TIEQ Lab can reproduce various indoor office settings such as heating, ventilation, and cooling, and be configured to test the integrated control and management strategies.
Zhang has authored/co-authored over 200 technical papers and 3 American national standards. He is Associate Editor of Journal of Science and Technology for the Built Environment (STBE, formerly ASHRAE HVAC&R Research Journal) and The International Journal of Ventilation, and serves as a Member of the Editorial Boards of Building Simulations--an international Journal, International Journal of High-Rise Buildings, and the International Journal of Architectural Frontier Research. He is a Fellow of ISIAQ and ASHRAE, and current Chairman of the International Association of Building Physics.