In the past year, ventilation was at the center of conversation around the mitigation of spread of COVID-19. The virus first detected in Wuhan, China, was airborne—able to infect people who breathe in contaminated air. Scientists simulated the aerosols ejected by an infected person into the air by coughing, sneezing, talking, and breathing. Enclosed spaces where the air is stale and still are especially dangerous since aerosols can travel farther than the six-foot social distancing standard and hang around the air for several hours.
Hopefully, the pandemic will change how the public thinks about indoor air quality and ventilation. Before the current global public health crisis, experts already knew that the lack of proper ventilation was terrible news.
Not Just COVID-19
It took a while before it became clear that COVID-19 spreads through the air. At the beginning of the pandemic, health authorities advised people to wash their hands and quit touching their eyes, nose, and mouths—entry points for the then-novel COVID-19 virus.
Proper hand hygiene, which involves handwashing, is essential. However, more recent studies showed that transmission through fomites, surfaces that carry the virus, is rare. The primary way COVID-19 spreads is through aerosols.
SARS-CoV-2 is not the only disease-causing virus to infect via exposure to aerosols. In a recently-released paper, researchers reviewed over 206 studies and found that the most dominant transmission route for most respiratory illnesses is not through fomites, which was assumed earlier, but through aerosols.
Because of their size, aerosols carry more viruses. They can penetrate deeper into the lung tissue than droplets that are much larger and cannot reach the lower respiratory tract.
The virus that causes the common cold, which affects millions of Americans every year, is already spread through the air. Influenza and its many strains cause the flu, and it infects people through aerosols. Tuberculosis is also airborne, and it can infect others through close contact.
Whooping cough, measles, mumps, chickenpox, and diphtheria are also airborne.
No Need for Further Studies
The practices and strategies that can help prevent the spread of disease-causing viruses through the air are already well-studied and proven. Scientists already know how to improve indoor air quality in buildings to prevent the spread of diseases.
Many people in the United States spend 90 percent or more of their time indoors. They are either at home, in schools or offices, in restaurants and retail stores, in movie theaters or gyms, and other enclosed spaces. These places can become disease hotspots.
In fact, there is a term used to describe a condition in which people who spend time in enclosed spaces experience symptoms that get better or disappear as soon as they are out in the open air. It is called sick building syndrome, which many health experts attribute to poor indoor air quality.
Simple measures such as regularly changing the filters in the heating, ventilation, air-conditioning (HVAC) system will dramatically improve indoor air quality. The impact will be more significant with high-efficiency particulate air (HEPA) filters in place. Building owners should also conduct testing, adjusting, and balancing to guarantee healthy airflow throughout the entire structure.
A Closer Look at Humidity
Humidity is also an essential factor to consider. The use of air conditioning typically removes moisture from the indoor air, making viruses more likely to spread. According to experts, viruses do not survive in environments where humidity levels reach around 50 to 60 percent. Low humidity also causes the sinuses to dry, leaving them more susceptible to infection. Too high humidity can still enable the spread of viruses through the air.
Previous research found that people took fewer sick days when the humidity in the school or office is kept at the middle range.
However, opening the windows is the most effective yet least expensive way to improve indoor air quality. This one act done a few times a day will freshen the air indoors, dispersing the aerosols floating around the room and preventing infections. Sunlight will also zap viruses in the air upon exposure, guaranteeing that everyone is breathing healthy air.
Experts believe that the experiences from the past year will permanently change aspects of life, including how many architects and engineers design buildings. While the COVID-19 virus has made life unbearable in the past year (and it seems the future), it also instilled the necessity of proper ventilation to the public. Hopefully, this directive can help end sick building syndrome and lower the risk of disease transmission in enclosed spaces. As such, offices, schools, restaurants, movie theaters, gyms, retail stores, and, of course, at home can be safer for all soon.