What are the causes of a drop in COVID-19 cases during the summer
Every summer we are experiencing a drop in COVID-19 cases and then in the fall, the cases start to rise and typically peak through the fall, winter, and spring months. Each of which is referred to as a wave. So with the current drop in cases is COVID-19 over or are we just experiencing a summer slowdown. To fully understand this, we need to look at each factor associated with the disease, reducing the probability of transmission between people.
The factors that should be considered are Sunlight UV Rays, Vitamin D influx Relative Humidity, and a reduction in spending time in inadequate indoor HVAC conditions, all of which are associated with spending more time outside. Catching an airborne disease is determined by three factors, the strength of the virus, how long we are exposed to the virus, and how strong our immune system is to fight the virus.
The virus which causes COVID-19 (SARS-COV-2) is highly sensitive to UVC lighting and at optimum conditions can eliminate the virus under certain conditions. So what happens is when a person infected with COVID-19 is participating in an outdoor event, such as a family Barbeque, Sporting event, or taking our dogs to the park any viruses that we naturally breathe out will be disinfected (“Killed”) as the suns UVC lights make contact with the virus. The probability of becoming infected by an infected person is reduced outside on a sunny day.
As we spend more time outside our body is absorbing vitamin D naturally from the sun which boosts our immune system, so if we become exposed to a virus our body can fight off the disease easier when we have a higher amount of natural Vitamin D in our system. Anything that helps boost our immune systems such as proper diet, exercise, and rest will help us reduce our probability of becoming infected.
During the summer months, the outside relative humidity increases the virus strength decreases such that at a low outside relative humidity (20%) it’s twice as likely to become infected with a virus than at high relative humidity (80%). This is significant because, on a rainy summer day when the sun’s UVC lights cannot reduce airborne viruses, the humidity will reduce its lifespan and strength.
The last effect covered in this article is a reduction in indoor activities where we have inadequate HVAC systems. A building’s HVAC system can be ineffective in Filtration, Dilution, and cross-contamination and when we are exposed to these conditions, the probability of infection among people can become quite high. In order to reduce this, a building’s HVAC system needs to be analyzed and often upgraded to improve the building’s indoor air quality which results in lower infection rates.
Atlabach Consulting is a world leader in providing Computational Fluid Dynamic Modelling of virus transmissions within a building along with Probability Of Infection Analysis to fully understand the health and safety of your occupants currently and afterward. www.atlabach.com