Huffman, a chemistry professor at the University of Denver, used the same modeling to advise DU on in-person learning for the fall semester. The purpose of his study is to provide a rough estimate of how risky a gathering could be to help aide decisions and encourage civic responsibility.
“If people go against my recommendation and that of the governor’s, the first thing to limit is time. Limit the number of people. Increase the distance between one another. Be careful about washing your hands and whenever possible wear your masks,” said Huffman.
The Centers for Disease Control and Prevention updated its COVID-19 guidelines Thursday, advising Americans not to travel for Thanksgiving. Gov. Jared Polis and state health officials have spent weeks warning Coloradans to take the spread of coronavirus seriously during the holiday.
Aerosol expert and DU professor Alex Huffman did a modeling study to show how dangerous gathering for one meal can be.
“One of the most dangerous pieces of sitting together for a meal is not just the indoor space, but we don’t have masks on,” said Huffman.
Huffman uses a Thanksgiving dinner scenario as an example in his model. Say there’s a 2.5% COVID infection rate in your community. If you have a two-hour meal, indoors, with 10 dinner guests, Huffman’s model suggests each person has 5% to 15% chance of getting infected.
The size of the room also plays role, but if possible, eat your turkey outside.
“If you choose to meet inside, there are various things you can do to try to reduce that risk a little bit. The most important thing is open the windows and ventilate the airspace, but you can also add some filtration,” said Huffman.
HEPA filters can cost several hundred dollars. Huffman says it’s possible to make a cheaper version for around $40. He suggests buying a 20-inch box fan from a home improvement store and taping a furnace filter on it. Then, place it somewhere in the central space of the room.
“Time also matters a great deal. If you stay in the same room as someone for many minutes, especially hours, the likelihood of you getting infected gets dramatically higher. The longer you stay in the room, the more breaths you take in. The bigger the room, the more those particles can mix into the volume and make it a lower concentration. The bigger the room the better,” said Huffman.
The CDC recommends having one person serve food and use single-use options, like plastic utensils. The CDC also says people should avoid going in and out of the areas where food is being prepared or handled.
If you’re planning to spend Thanksgiving at another household, Polis says you should have begun quarantining last week.
“The whole reason I did that modeling study is because I heard so many people saying, ‘I know I shouldn’t meet, but it’s just this one time.’ That is a really dangerous idea. I put these numbers together to try to convince people how dangerous this was,” said Huffman.