Science vs. COVID
COVID-19 is largely spread by respiratory droplets. Large droplets drop to the ground quickly but smaller droplets (~.3 to 3 micrometers) can stay in the air for over 10 minutes. Fortunately there is a low cost method to remove these droplets using a simple Box Fan and Filter. The goal is to get as much air through the filter as possible to increase your Air Changes per Hour (ACH). Lets get started.
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What You Need
There are many variations on the design but the basic components are the same. You need a Fan, the filter(s), and something to attach them.
The Filter
Air filters are often categorized by their Minimum Efficiency Reporting Value (MERV) rating. This measurement scale was designed to compare the performance of filters across a range of particle sizes. The higher the rating the more effective a filter is at trapping smaller particles (see graphic). A MERV 13 filter provides ~85% efficiency at trapping particles in the range of interest for COVID [Source].
The Fan
Box Fans are fairly standard with a size around 20 inches by 20 inches. The most important thing for this project is that the power cord comes out of an edge (usually the bottom) versus having a power cord to the middle of the fan. While there is relatively little difference between models in the lower price range, they can vary is noise levels and aesthetic appeal.
The Attachment
A good seal between the fan and filter helps reduce “leakage” or the act of air not going through the filter. The simplest approach is simply using table all around the edges of the fan/filter interface. You can also use physical pressure with clips, frames, or even gravity. The kits include a roll of white tape (the most visual appealing) but we also have 3D printed clips that are available for you to download and print on demand.
Educational Opportunities
The fan/filter kits serve as an excellent educational resource in addition to reducing the spread of COVID. Having students explore different configurations with multiple filters, filter thicknesses, and overall geometries creates a way to integrate the kit into Mathematics, Science, and English Language Arts. Working with teachers, we have a variety of lesson plans ready to go with more being added regularly. We love giving students the chance to engage with their lessons as that is how we best learn ourselves. Check them out and feel encouraged to submit your own!
About Us
Hugh Churchill is a Quantum Physicist at the University of Arkansas with a passion for using science to build a better world. The box fan and filters aren’t a novel idea and they have been proven to be effective to help families impacted by smoke from forest fires all the way to dealing with seasonal allergies. As COVID is rapidly spreading and schools are starting their semesters, we wanted to make sure that teachers, parents, students, and administrators knew there were low-cost options that are proven to make a difference. Learn more about Hugh and this effort in the video below.
Expand Options with 3D Printing
We made custom clips that you can print and use with your own setup. They work well to help reduce leakage but tape works as good (or better) in many cases so don’t feel like you NEED a 3D printer. How would you change them to improve performance?
Expand Options with 3D Printing
We made custom clips that you can print and use with your own setup. They work well to help reduce leakage but tape works as good (or better) in many cases so don’t feel like you NEED a 3D printer. How would you change them to improve performance?
What the Experts Say
Want to Get Involved?
We would like to connect with philanthropic groups, supply chain experts, teachers, and decision makers