10. Indoor Air Quality is Covid Prevention Too
They're one in the same
In the northern half of the United States, where frost has returned to chilly sidewalks and frozen leaves, Covid has returned, too.
One of the likely causes for this is the seasonal retreat to the warmer indoors, to welcome our (hopefully vaccinated) friends and family members. To sit around a kitchen table and tell jokes, share a meal, or just be with other humans.
Even in fully vaccinated homes, Covid can still lurk. Vaccines do a great job at decreasing disease severity, and almost surely reduce the risk of transmitting the infection from, or to, others. But we can still bring it home from our workplaces or our schools.
In other words, we’re not out of the woods just yet, even if I took (and take) a more wishful, rosy outlook.
As the holiday seasons approach with full force, and holiday gatherings fill your schedule, what can we do to reduce this risk? Quite a bit, in fact. Testing and air quality are our best hopes.
Testing, Testing, Testing
There is no comfortable way to ask about whether someone is vaccinated, but vaccines are the most effective strategy to reduce risk to you and your family and your other guests. Do your best. I get that it’s awkward.
But testing is still very important and is a strategy to consider. It’s probably one of the more difficult ones to insist upon as we approach the holidays.
Contrary to popular belief, free or low cost Covid testing is still available in every state in the US. Sure, there are plenty of stores or clinical offices that either charge you for the test, or charge you for an office visit (but toss in the test for ‘free’). Skip these. Go to your local health department. Taxpayers (you) have already paid for a bunch of them.
If you’re planning to host some holiday gatherings, think about getting a test a few days before you host visitors - if it’s negative, keep your interactions with others limited as much as you can. Even if your guests don’t thank you, I will - being tested is important for public health. So thanks.
For those who are coming to visit, ask them nicely to get a test. Tell them that it is important to you to keep everyone safe. My appreciation probably won’t do much for you in this case, but yours will.
The problem is that Covid testing numbers are generally flat, with around one million tests per day across the US, despite the fact that Covid is on the rise. Testing has to scale up with the threat - without this, we are clueless where we will find this pernicious worry.
The best kind of test is a molecular test, which looks for genetic material fingerprints of the virus (sometimes they’re called PCR tests). Antigen tests are available in your local drug store and, while they aren’t as good as molecular tests, they report results in 15-20 minutes and should be the first thing you reach for if you have a close contact with someone who might have Covid.
In fact, it’d be wise to ask Santa for a few rapid/at-home tests to have around the house, just in case.
The Air Around Us
There is little doubt among public health scientists that Covid is transmitted as an airborne agent. Every spoken word, sung song, or even a deep exhale by an infected person can represent a volcano of risk for those around you. It’s the origin of six feet of social distance - beyond this distance, risk goes down because we are further away from the source of infection, even if risk of exposure never fully goes away.
Gathering together is a common thread to any holiday celebration. But this is where it is tricky to keep that six-foot distance (and with enough holiday cheer, even two feet can be tricky). So let’s talk about some things you can do, when great Uncle Leroy and Aunt Elda come for a visit, and you want to reduce everyone’s risk without thinking too much about it.
Keep guests outside
Depending on your local weather, consider an outdoor event. Okay, this won’t work in many places - for example, Fairbanks, Alaska, where today’s high temperature was 1 degree F (-17 Celsius). But in more temperate climates, move your party outdoors if you can. Backyard or front porch gatherings can be wonderful, and it’s a simple and effective tool to reduce risk. Hang some lights, bring out a cooler, light a outdoor fire pit and enjoy.
It doesn’t mean indoors is entirely off limits. Some will be cold. Nature will still call. Glasses will need to be refilled with ice. Think of being indoors like seasonal eggnog - best in small quantities, and a great peril when too much is consumed.
Open the windows
As a kid, I always laughed at the line “Tore open the shutters and threw up the sash” in Clement Moore’s A Visit from St. Nicholas (also known as ‘Twas the Night Before Christmas). But it turns out that was, and is, pretty good advice.
If you have to be indoors, opening windows, even just a crack, creates a cross breeze and allows fresh air into your home. Yes, it can be mighty chilly air, but it’s also very likely to be Covid-free. If there’s a chance someone is infected, this dilutes stale air in your home, and decreases risk to your and your guests. Goose your thermostat a couple of degrees, or toss another log on the fire, and people will just think you’re trying to cool off the house. You don’t have to tell them you have other motives when you open those windows.
And, you can tell them this way it’s easier to see that miniature sleigh and eight tiny reindeer.
Active Ventilation is Important
If opening windows isn’t reasonable, use some of the fans in your home to force air in to your gathering. Do you have an attic fan that draws air from your home? Turn it on. If not, maybe a standard box-fan blowing out a nearby window. These push stale from your home, drawing in fresh air from the outside. But do be very cautious about fireplaces and open burners that might be in operation - attic fans can cause a dangerous backdraft.
Maybe you have a vented stove fan? How about a bathroom fan? These fans are pretty puny compared to a heating system fan, but every little bit helps.
Want to see this in action? Buy or borrow a carbon dioxide (CO2) monitor and place it in a crowded room. Watch the numbers rise from exhaled CO2 from breathing. Turn on a fan, or open a window, and watch it drop.
If you don’t believe me that people contribute to poor indoor air quality, this graph is from my windowless classroom of ~130 students earlier this semester. It should be pretty obvious that class is from 4PM to 5:15PM when CO2 concentration steadily increased from those exhaling lungs in that stuffy room.
CO2 levels seen here are not necessarily hazardous, but they indicate that exhaled breath is everywhere. Yes, we are breathing in air that someone else just exhaled. That’s how infectious diseases jump from person to person, too.
These days, CO2 in my classroom rarely goes above 800 ppm during class because the ventilation system is running at full bore.
Turn on your HVAC system
For those lucky enough to have a forced air ventilation system, install a new air filter and force your fan into ‘on’ mode at the thermostat. Some systems have a minimum run time for the fan (mine is normally set to 10 minutes per hour). Set it to 60 minutes per hour for the duration of your gathering. For most, this won’t bring in fresh air to your space, but it will filter the stale air, returning it quite a bit cleaner and reducing that risk.
And make sure you have a MERV13 or better filter.
Run a HEPA filter, or build your own
If you don’t have the ability to open windows or turn on fans, consider a portable filtration device. HEPA filters, which are available for residential use, are a few hundred dollars and can be placed in rooms where people congregate. This doesn’t draw in fresh air, but it recirculates and through a filter to remove particles from stale air, much like a HVAC system. They can sit in the corner of the room in which you are gathering and quietly filter away.
If a few hundred dollars is too rich, consider building your own. If you can assemble a cardboard box, you can build your own filter device. These are little 20-inch cubes that have a box fan mounted to it, passing stale air through one of four MERV13 filters to provide cleaner air.
Feel free to decorate either with lights or ribbons or garlands and get it in to the holiday spirit.
Be as Safe as you Can, as Much as you Can.
Risk will never approach zero, but you can take measures to protect you, your family, and your holiday guests. You can take an active role, and insist on things like vaccines and testing for your guests. But this can be tricky, especially in a world that is tired of Covid, or with those who still refuse to recognize the risk.
Or take a passive role, where you efforts are subtle and more hidden, and might look more like a party host concerned with your guest’s comfort. Your efforts will not eliminate risk, but it will lower it for both you and your guests.
I’ll toast to that. As should we all.
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