Nobody likes being sick with a virus. It can feel even worse if your loved ones get sick. But you can keep your family healthier by learning ways to prevent viruses from spreading.
Some viruses can live on surfaces. You become infected when you touch them and then touch your eyes, nose, or mouth. But many viruses can spread through the air. These are called airborne viruses. A range of illnesses—from mild colds to influenza to COVID-19—are caused by airborne viruses.
Every time you talk, sneeze, sing, or cough, you breathe out more than just air. You also exhale lots of tiny fluid particles. These come in a wide range of sizes. The larger ones, called droplets, fall quickly to the ground. These typically travel less than 3 to 6 feet. But the smallest particles, called aerosols, can hang in the air for minutes or even hours. They are able to travel through the air further than 6 feet.
Dr. Donald Milton, who studies airborne viruses at the University of Maryland, recently measured how often virus is exhaled by people with the flu. He found that people did not have to cough or sneeze to expel these viruses into the air. The flu virus was detectable in the air after normal breathing and talking. Other illnesses are also caused by viruses that are airborne. These include the common cold, respiratory syncytial virus (RSV) infections, measles, and severe acute respiratory syndrome (SARS).
Clearing the air . . .
Ventilation and humidity are important factors
How much virus is floating around in the air depends on where you are. Indoor spaces tend to be poorly ventilated compared to the outdoors. In a building with poor ventilation, there’s nowhere for the aerosols to go. Outdoors, aerosols can float off or blow away.
When aerosols collect in the air, you’re more likely to breathe them in and get infected. That’s why many outbreaks of viruses are traced to places with poor ventilation where people were talking loudly or singing—such as restaurants, bars, or places of worship.
Good airflow can quickly clear indoor air of aerosols. This lowers the chance that people will breathe in enough viruses to become infected.
Some viruses, like the flu, are known to spread more rapidly during the colder seasons. People tend to spend more time indoors when the temperature drops. But other factors may also affect how easily viruses spread during cold weather.
Certain viruses, including the flu, last longer in cold temperatures. Humidity, or how much water is in the air, drops in colder air. Humidity can affect how viruses spread. One reason may be that moisture aids the mucus flow in our airways. This flow helps to clear out viruses.
Studies also suggest that the flu spreads better at lower humidity. Dr. Seema Lakdawala, a flu researcher at Emory University, has found that flu viruses in aerosols can survive over a wide range of humidity levels. So, humidity might not harm the viruses themselves. Instead, it may affect their ability to stay in the air. At lower humidity, Lakdawala explains, water from aerosols will evaporate. This causes them to shrink, allowing them to stay in the air longer and travel farther. At higher humidity, aerosols might absorb water from the air, causing them to fall faster.
Tips to prevent the spread
With all these viruses floating in the air, what are the best ways to stay healthy? Getting CDC-recommended vaccines can help your body fight off germs. Maintaining a healthy lifestyle can also help keep you from getting ill. That includes a healthy diet and physical activity.
Face masks trap fluid droplets coming from your mouth and nose. This can stop viruses from spreading through the air. Masks can also protect the people wearing them.
Researchers are studying other ways to help lower the number of viruses in the air. These include improving building ventilation, air filtration and using portable air purifiers.
No single strategy will be 100 percent effective at preventing all illnesses, but the following combination of tips may help reduce the spread of viruses.
- Maintain a healthy immune system to help your body fight germs.
- Stay up to date with all CDC-recommended vaccines.
- Stay home when you’re sick so you won’t spread your illness.
- Improve indoor ventilation and air filtration. Open windows, use portable air purifiers with a HEPA filter, and turn on fans. Change your HVAC system filters frequently.
- Wear masks if you are in a high-risk space or if your immunity is low.
- Practice good hygiene. This includes washing hands with soap and water for a minimum of 20 seconds.
- Avoid touching your face, nose, eyes and mouth.
- Frequently disinfect high contact surfaces such as countertops, door handles and places where people place their hands.
