We answer common questions about the coronavirus crisis. Send us an email at goatsandsoda@npr.org if you have any questions. The subject line should be: “Weekly Coronavirus Question.” You can find an archive of our FAQs right here.
We’ve all been through a crash course over the past two years in how to prevent and treat respiratory infections.
We have learned that ventilation is the best way to clean air. Fresh air flow through windows and doors, and filtration (removing any particles from the air using a filtering device), are both important to prevent COVID and other respiratory diseases. Experts knew this for years. The public is now starting to understand.
Researchers believe that airborne transmission is possible, particularly in indoor environments. However, it’s not clear how much. This is how you can lower your risk, just in case.
Richard Corsi (dean of the University of California Davis College of Engineering) says that indoors is where most of the air we inhale during our lives. Viral particles can also linger in unventilated air, increasing the risk of getting sick.
These particles are invisible. Abraar Karan, a Stanford University infectious disease specialist, says that if people could see COVID in their air it would be a lot easier to understand.
What can you do as an individual to make the air cleaner, safer, and more comfortable at work, home, school, or the gym?
We asked three experts to answer this question.
How can I improve my ventilation?
Karan states that it is important to increase airflow in the home.
Linsey Marr from Virginia Tech, professor of civil engineering and environmental engineering, recommends that you open windows whenever possible. “Especially if they can be opened on opposite sides of a room, so cross-ventilation air aEUR” is possible.
Cracking windows is a great way to open some windows, even if they aren’t all open or not fully open. Marr states that they don’t need to be open wide.
It is also helpful to open doors in shops or gyms.
Marr collaborated with the owner of the local gym to improve ventilation during the pandemic. Because the gym did not have central air conditioning, it could not rely on filtration. It was the easiest thing to do was open the doors. Marr states, “I calculated how much benefit we would receive from opening the doors, and it was a lot. So we kept them open all year.”
Marr, who was responsible for the facility’s advisory and kept track COVID developments, said that there was no transmission. She says that even though staff were exposed to the virus in other locations, it doesn’t appear to have been passed on at work.
What can I do to improve my home’s filtration system?
If you have an HVAC system aEUR” forced air heating/cooling/ventilation aEUR” you can do two main things: run the fan more and upgrade the filter in order to catch more viral particles. All HVAC systems have replaceable filters that trap allergens, dust and other particles in the air.
HVAC systems don’t typically circulate air 24/7. They only run part of the time aEUR when indoor temperatures drop.
Corsi advises that you run the fan as often as possible to ensure the HVAC system is working properly.
Marr says that you can turn on additional fans if the windows are opened to let in fresh air. They can make the room noisy but can help create airflow by drawing the air upwards toward the ceiling.
However, when windows are closed, many home HVAC systems simply circulate the same indoor air. This means that the filters you have may not be effective in catching tiny viruses particles. You can replace those filters with better-quality options such as a filter with a minimum efficiency report value (MERV) 13.
Corsi states, “If you can place a MERV-13-filter in your HVAC system, and if the fan is circulating continuously then that will remove a lot more aerosol particles.”
He says that most school ventilation systems can be upgraded to MERV-13 filter.
However, he warns that not all systems are capable of handling the more efficient filters. It’s a good idea for an HVAC specialist to inspect your system. Your system shouldn’t be too straining to pull air through incompatible filters.
HEPA is another type of filter that removes viruses from the air. However, most HVAC systems don’t support HEPA filters. You can still get an HEPA portable air purifier.
Can portable purifiers help?
Marr states that HEPA means it filters out more than 99% of air. In general, the price of a unit is determined by how much air it can move through. This means that the larger the unit, it will cost more.
It is important to choose the right-sized unit that can purify the air in a room within an hour. Marr says that there is a huge difference between a $50 unit that cleans the closet in a reasonable time and a larger unit that costs $200 to $300 that cleans the bedroom in a reasonable time.
She says there are better options. For example, you can make your own fan using a box fan. This is a small, portable fan that has a propeller blade, and fits in most windows aEUR”, MERV-13 filters. Marr says that this is more efficient than the expensive HEPA units.
This DIY filter, also known as the Corsi Rosenthal box, is simple and cheap to make. You create a square with four filters on each side and the fan at the top. The bottom is taped with a piece of cardboard. This homemade purifier can be placed anywhere an expensive purifier would go.
Karan agreed. “The CorsiRosenthal box, which is basically a low-cost method to improve ventilation, is a good option.”
Corsi also agreed to aEUR” partly because he was among the inventors. He thought that it would be more economical to provide some air filtration when he first came up with the idea during the pandemic. It is an aEUR” and the materials are between $80-$100.
Corsi states, “But I also did not realize how incredibly efficient it would be.”
According to another study, the boxes are up to 2.5 times as effective as a $300 HEPA filter unit.
Whatever portable filtration system that you choose, be sure to position it correctly. It is best to not place the purifier in a corner as it could recirculate the same air. For the same reason, keep your purifier at least a foot away from the wall.
Corsi suggests that you have two or more units for larger rooms. You can place them in different areas of the room so that the air is filtered well.
Are those tiny travel-sized air filters any good? Any benefit?
HEPA purifiers are small devices that fit in your pocket or bag. These small devices might seem to be of little help, but do they really work?
Marr states, “They should, but you’d like to direct the flow of airflow.” This can clean a small surface of air.
Make sure to position the clean air stream as close as you can to your face, and place it on the table or desk directly in front of you.
Corsi states that if you use them so that the air is directly in front of your desk, and it’s blowing up towards your face, it can lower the concentrations of aerosols you’re inhaling. While I wouldn’t emphasize their benefits, there are some.
These purifiers can be purchased for $30-$50 and provide additional protection when you travel, eat at restaurants, or go to work or school.
Do I need a CO2 monitor?
Marr states, “If you’re very cautious, that could be a useful tool to help you assess the risk in different places.”
The CO2 monitors measure the amount of carbon dioxide in the air. Although they can’t determine how much COVID is present in the air, they can tell if it is high.
“If the CO2 reading is below 1,000, it’s probably pretty good. Any reading above that level is an indicator that the space is not properly ventilated. You’re inhaling a lot of other people’s exhaled air at high rates. Marr calls it “drinking backwash” which Marr uses to describe the act of drinking other peoples’ spit while having a drink.
These are not rigid rules. They depend on the size of the space, the number of people there, their masks, and the number of cases that are circulating in the area.
Corsi states, “I don’t like using CO2 monitors to do very specific analysis.” They are not precise. He says they can be very useful in determining whether the air quality is very high or low.
Do I have to wear a mask if my ventilation is improved?
You’re less likely get sick if you improve the air quality. It’s not always 100% effective.
Experts all agreed that wearing masks is the best way to decrease your chance of getting sick, and if you do get sick, aEUR” spreading the virus.
This means that you should continue to cover up indoors in public places when the cases are high as they are now in the U.S.
Wearing a mask is a good idea if you are sick or someone in the household is. This will prevent the virus from spreading to your home.
Marr states, “If someone is sick, you should try to have them wear masks to reduce the virus that gets in the air.” To protect yourself, it is a good idea that you cover up when you are near them.
Good ventilation will prevent me from contracting COVID if a loved one becomes ill.
Yes! Although it may require some effort, you can stop transmission at home.
Karan, an infectious disease doctor has seen many patients who contracted illness at home through family members. He said, “That’s what we are having a really difficult time with right now.”
Karan insists that “I know there are ways to make your home safer aEUR”.
To prevent cases spreading at home, all of the following advice is important: Open windows, use a fan to blow air out windows, wear masks for source control, improve air filtering.
Corsi suggests that you keep the door shut in the patient’s room and use a fan to blow the windows out. This will ensure that the “emissions” they are releasing into the room don’t spread to the rest of the house. This will help others in the house avoid getting infected.
Do I need to press for improved air quality in public places?
Sometimes, you’ll find yourself in areas where air quality is not controlled, such as at work, school or restaurants.
It’s worth asking about the air quality improvements made by these places. Talk to your teacher if you are concerned about your child returning to school in fall.
Karan states, “We must hold businesses responsible and then the government accountable,” Karan said. This is to ensure that ventilation systems are upgraded and indoor air quality standards are established.
He says, “It’s more than COVID.” Cleansing the air can also reduce respiratory viruses like RSV and flu, as well mold and allergens.
It is easy to feel that COVID precautions are no longer necessary. This is not the best thing we can do. Karan states that people need to hear that there are solutions.
“We are not going to eliminate COVID. We can, however, reduce the transmission of COVID significantly.
His verdict: “Ventilation the way forward.”
Melody Schreiber (@m_scribe), is a journalist who edits What We Didn’t Expect: Personal Stories about Premature Birth.
