New study shows how airborne contaminants are spread and the importance of ventilation. Studies also show how an upper-room UVGI system is effective for inactivating bioaerosols.
As schools being to open up all over the country New York City has put in strict protocols which has helped lower in-school transmission. A new study which models the flow of air provides a visual representation of how easily airborne pathogens can be spread around a room when no outside air is brought in to help ventilate. Besides mask wearing students must practice social distancing and classrooms must have windows that open. The modeling is from a typical classroom from the pre-Covid era with about 30 students and it shows how ventilation helps. It also visually shows the movement of air and where the contaminants travel depending on the where an infected student is sitting. This scene is based on a real public school classroom in New York City.
In the first image you can see how a typical classroom (NY) is situated with multiple students sitting around a table. In this scenario there was no concern about the transmission of airborne contagions. In our new world, post-pandemic with an easily transmissible virus which can be harmful and in many instances deadly.
In the classroom below just nine students are seated now, all wearing typical protective face masks. They all face forward and are sitting six feet apart. Like most classrooms in public schools in New York all of the windows are closed. he room would lack When there is an airborne virus such as COVID-19 even with mask and reduced class size the room with no ventilation of any type an airborne virus would still spread and infect. Even with a mask on each student about 3% of the exhaled is also breathed in by other people.
In the below image even students who may be healthy and feel healthy can still be asymptomatic carriers who can transmit the virus. In the modeling below you can see what happens visually when an infected student is introduced to the classroom. The red colored lines trace the student’s warm breath as it rises and begins to disperse contaminated respiratory aerosols throughout the room with the contaminants darkest. As it clearly shows air is rising to the top of the room where an upper room germicidal fixture using UV light would be helpful.
While we still do not know exactly what level of contamination presents the greatest risk of infection, “exposure is a function of concentration and time,” said Joseph G. Allen, the director of the Harvard Healthy Buildings program and an environmental health expert.
Within a short amount of time, the room approaches its peak level of contamination without any fresh air coming into the space, or any type of air purification system. As shown in the image below the contaminants continue to circulate throughout the room potentially infecting a person or teacher. Again the darker the color a higher level of contamination. All shown there is a high level of pathogens now circulating in the room.
Notice the image below where is clearly shows in a visual representation of where the worst contamination is, which is why an upper-room UVGI system is ideal for air cleaning.
All experts agree that good ventilation is the most effective and practical way to rid a space of contaminants. The Healthy Buildings program recommends four to six air exchanges per hour in classrooms, through any combination of ventilation and filtration. Our upper ceiling mounted UVGI is one tool that can help remove pathogens without taking up valuable classroom space. In New York City they have mandated every classroom have at least one operable window to help with ventilation, even in the winter. Below you’ll see what happens when a window is opened.
In the image directly above you can see how the fresh air dilutes the contaminants as they move around the room. “Simple and inexpensive measures can make schools much safer,” said Scott E. Frank, whose engineering firm JB&B assisted with these simulations. We would also recommend where possible to introduce fresh outside air along with an air purification system.
Air Purifiers are an effective method for removing bioaerosols.
Our commercial upper-room UVGI uses UV-C light in the wavelength of 254 nm to emit nonionizing electro-magnetic radiation with a substantial amount of spectral power. UV-C, which has been around for over 80 + years to disinfect, uses the light radiation which penetrates microbial DNA to cause damage sufﬁcient to interrupt cell replication. Upper-room air UVGI is achieved by suspending lamps from the walls or ceiling. Our product, called the “Airolizer” is suspended or recessed mounted in an enclosed stand-alone housing so the UV lamps are shielded. Since air flow studies show how pathogens move up our system is mounted high up in the ceiling in order to maximize UV radiation exposure to airborne microorganisms.
Our system uses both UV-C light with a Ti02 catalysts to provide a powerful method inside a sealed chamber to destroy microorganisms which can be harmful to anyone who is exposed to them.
Many studies have been performed evaluating the performance of upper-room air UVGI for inactivating bioaerosols. In-room air cleaning has been used to effectively reduce indoor particle concentrations in many settings and can be achieved by operating a device like the Airolizer which continually circulates upper room air through a series of ﬁlters medium designed to collect large particles then send into an irradiation chamber to destroy pathogens and contaminants, including viruses.